Hans Püttgen: The Energy Challenges of the 21st Century.

Vernon Roan: Alternatives for Transportation Energy.

Christine Ehlig-Economides: Unexpected Difficulties with Geologic CO₂ Storage.

Summary: Just when public policy leadership has embraced as gospel the concept of man-induced atmospheric carbon dioxide as the cause of global warming, there is emerging evidence that CO₂ and man have nothing to do with global warming or climate change. If the erroneous belief that atmospheric CO₂ is responsible for global warming is incorporated into public policy legislation the unnecessary extra energy cost will be incalculable.

Introduction

• There is strong evidence that the earth’s surface temperature is increasing.
• There is strong evidence that atmospheric CO₂ levels are increasing and isotope analysis indicates that much of this increase comes from man’s activities – primarily the burning of fossil fuels.
• Since CO₂ is a known ‘greenhouse effect’ gas there is a presumption that its increasing atmospheric presence is causing global warming or ‘climate change.’
• Careful analysis of the data assembled by the Intergovernmental Panel on Climate Change (IPCC) confirms that the earth is warming but that CO₂ has nothing to do with it.
• The data indicate that whatever changes in temperature the earth experiences are a result of changes in radiation from the sun rather than the increases in trace greenhouse gases in our atmosphere like CO₂.

Background

The concept of anthropogenic (man induced) global warming began as speculation on the part of a few scientists who wondered if all the CO₂ mankind was spewing into the atmosphere was being absorbed by plant life (or the oceans) or was building up in the atmosphere with possible unintended consequences. In the 1950’s scientists began precise measurements of the CO₂ content of the atmosphere. After a number of years, it became evident that atmospheric CO₂ was indeed increasing. Isotope analysis indicated that man’s burning of fossil fuels was the source of most of this build-up rather than ‘natural’ sources like volcanoes.

Using air bubbles in ancient ice cores from Antarctica and Greenland it was possible to go back in time some 650,000 years and determine historic atmospheric CO₂ levels. Proxy methods such as deuterium ratios in the accompanying ice were used to estimate historic temperatures. There seemed to be a correlation between historic atmospheric CO₂ levels and global temperature.

During World War II and the decades after, new techniques for measuring the earth’s surface temperature proliferated. Weather balloons became common. Sea weather buoys were added to ship measurements. New land weather stations were added. Satellites were put on line. The data from these different methods didn’t always agree. Some scientists contended the earth was not warming.

The Case for Global Warming

In the 1970s, a cadre of very competent scientists were convinced the earth was warming, and they knew atmospheric CO₂ was increasing. The suggestion was that the warming was caused by the increasing CO₂. But contrarians pointed out that the earth, at that time, was not warming.

In 1988 the IPCC was formed as a coalition of scientific and public policy advocates who defined ‘climate change’ as ‘a change in climate as a result of man’s activities.’ By now they had added the clearing of forests, cement making, cattle raising, etc., as well as the use of fossil fuels, to the list of man’s activities that cause global warming (now dubbed ‘climate change’). The case for anthropogenic climate change was clear and compelling to many scientists. Yet the opposition remained steadfast and centered around the argument that the earth was not warming.

The wider scientific community entered the debate. Biologists noticed the habitat of the arctic tern was moving north while Central American golden frogs were moving up the mountains to a cooler environment. Glaciologists noted that glaciers were thinning and receding. Sea Ice was forming later and melting sooner. Tundra was thawing. More and more proxy rising-global-temperature evidence poured in from many different lines of inquiry. Combined with the unquestioned increase in atmospheric CO₂, the main thesis of the IPCC became more and more established: The earth was warming and it was being caused by man’s activities.

The tide of public opinion began to shift. The confrontational chairman of a major oil company retired and was replaced by a ‘go along to get along’ moderate. A leading republican senator and presidential aspirant announced: “The debate is over.” With most of the scientific community and much of government and the public behind them the IPCC consensus movement seemed unstoppable.

The Greenhouse Effect

We know the earth’s atmosphere has a ‘greenhouse effect’ because a ‘black body’ in space receiving an equivalent amount of solar radiation would be cooler, and because our day-to-night temperature excursions are more moderate than those experienced by bodies like mars and the moon with little or no atmosphere. It is the known existence of this ‘blanket’ that leads many scientists to believe that changes in its characteristics could lead to global warming.

A look at a handbook table of the constituents of the earth’s atmosphere will note that the ‘big three’ – nitrogen, oxygen, and argon – collectively comprise 99.9% of the atmosphere. None of these is a greenhouse gas. The next most abundant gas listed is CO₂, at 0.038% and it is the first and apparently most important of the greenhouse gases. These handbook tables, however, are for ‘dry’ air and do not include water vapor which is some 13 to 33 times more abundant than CO₂ in the atmosphere and is also a powerful greenhouse gas. Water vapor is a wild card in the atmosphere. Its percentage changes with altitude, temperature, pressure, and geographic location. Thus it is hard to pin down. This variability makes it hard to lay out a comparison of the relative ‘greenhouse effect’ importance of water vapor vs. CO₂. Further compounding the problem is that on a molecular basis the ‘greenhouse effect’ for a gas is determined by its absorption bands within the infra-red spectrum and since there is a lot of overlap to the bands of CO₂ and water vapor, again we get into an interpretation problem. If a band overlaps how do you allocate the ‘effect’– do you split the difference or do you allocate according to relative abundance? Estimates of the greenhouse effect of CO₂ vary from 26% of the open sky (perhaps 10% overall) in one model cited by the IPCC down to about 0.15% in a model cited by contrarians. If CO₂ plays a very minor role in the greenhouse effect (as some of these models would suggest) then dramatic increases in its presence in our atmosphere would have no effect on our climate and the greenhouse effect we observe would be overwhelmingly due to passive water vapor.

Aside from the modeling work by Kiehl and Trenberth [Ref. (3)] on the earth’s energy budget, there seems to be very little mainstream scientific inquiry or experimentation in this general arena.

The New Debate

From the beginning, CO₂-caused global warming was at the low end of the scale of scientific confidence or surety. The entire case rested pretty much on two observational points. Both showed an apparent correlation between atmospheric CO₂ and global temperature but neither had an established cause and effect relationship.

At this point we have a disagreement over the facts. On the one hand, water vapor is declared to be the dominant greenhouse gas with CO₂ playing an almost insignificant role; while on the other hand CO₂ plays a significant role along with water vapor. Based on this disparity we would have to concede that if the first case is true some factor other than anthropogenic changes to our atmosphere must be causing our globe to warm.

So let’s reframe the debate: The globe is warming (we all now agree). But we don’t really know what is causing it to warm. It could be increasing atmospheric CO₂ or it could be something else. So let’s look at the observational evidence. The IPCC has plotted a composite earth surface temperature vs. time [Fig. (1)].

Figure 1. Clearly the earth’s surface temperature is rising over the long term just as the IPCC said. But what about the period from 1945 to 1979 ? Here the earth’s temperature was cooling while atmospheric CO₂ was increasing as a result of the post-World War II industrial boom. How could this happen over a 35 year period if atmospheric CO₂ causes global warming? One suggestion was that aerosols (particles) spewed into the air from the industrial boom caused a ‘dimming’ by reflecting the sun’s incoming radiation. Unfortunately while reflective particles from volcanic eruptions like Tamborra in 1815 (which caused “the year without a summer” in 1816) can cause short term dimming, soot particles (like stack emissions from coal power plants and older automobile exhausts) do just the opposite and absorb incoming radiation from the sun. [Image source: ref (2), Technical Summary, p37.]

So the first purported piece of observational evidence of CO₂ causing global warming begins to disintegrate as CO₂ and global temperatures diverge for a 35 year period.

Now lets look at the second piece of evidence, the ‘hockey stick’ graph made famous by Al Gore in his lecture series// documentary movie// book (Fig.2).

Figure 2. (Deuterium ratios in accompanying ice used as a proxy for temperature).
This graph shows peaks of global temperature over some 650,000 years coinciding with peaks in atmospheric CO₂ content. The implication of course is that the extra CO₂ is causing the higher global temperature and the minima are the various ‘glacier ages’. [Image source: ref (2), Technical Summary, p24.]

Actually the glacier age cycles are pretty well established as being caused by the near and far points in the geometric relation of the earth to the sun (the Milankovitch cycles) so attempting to pin those cycles on CO₂ was a stretch at best. Actually the mechanism here is: As global temperature increases (as a result of increased solar irradiance) some of the vast quantity of CO₂ dissolved in the world’s oceans is released into the atmosphere. Thus the increased CO₂ is a result of rising temperature rather than a cause.

At the far right hand side of figure 2, note that CO₂, methane, and nitrous oxide have risen to levels above that of ‘natural variability’ – probably as the result of man’s activities. But also note that global temperature is holding steady with no correlation to the continuously rising trace gases. This is another example of a ‘divergence’ demonstrating that there is such a small amount of these gases in our atmosphere that they have no effect on global warming.

The two main points of observational evidence used by the IPCC to ‘unequivocally’ demonstrate that CO₂ is the cause of global warming are now in shambles… and it definitely looks like something other than atmospheric CO₂ must be responsible for global warming. But what could that be? Obviously, increased solar irradiance.

The effect of the sun on global temperature is complex. We have the three different Milankovitch cycles, the solar sunspot cycle, and changes in solar surface intensity (like solar storms and flares) all affecting the earth’s incoming solar intensity. There is one highly publicized recent study that concludes that recent global warming is not related to increased solar irradiance [ref. (6)]. This paper selects from contradictory data from different satellites over the past two decades and extrapolates back in time. Even the global temperature data used differs markedly from the now well established IPCC baseline data. This paper, while painstakingly detailed, does not instill a high degree of confidence in its basic data or its conclusions.

On the other hand, figure 3 (from the IPCC data) shows another study of solar irradiance.

Figure 3. Although the scale is a little different from figure 1, this figure shows the increasing incoming radiation from the sun during the same time span that the temperature is rising in figure 1. Even a suggestion of the dip from 1945 to 1979 can be seen. Although all of the earth’s energy budget figures are too uncertain to draw definitive conclusions, it is interesting to note that if we use the change in total solar flux over the 20th century of about 0.8 watts per square meter from figure 3 as a percentage of the earth’s annual incoming solar radiation of 342 watts per square meter [from ref (3)], we get an increase of about a quarter of one percent. The average mean global absolute temperature increase over the same time span is also about a quarter of one percent. On the other hand an increase of about 25% in the CO₂ content of the atmosphere during the same period shows no correlation. [Image source: ref (2), Chapter 2, p190]

Conclusion

These points of observational evidence make a convincing case:

• Atmospheric CO₂ and other trace greenhouse gases are indeed increasing but collectively they are such a small component of our atmosphere that they have no effect on the earth’s temperature.
• Water vapor, which is much more abundant than CO₂ in the atmosphere, causes the entirely passive ‘greenhouse effect’ that the earth experiences.
• Increases in the intensity of the sun cause global warming.
• Man-induced global warming is a modern myth.

The Future

The sooner we gain energy ‘independence’ the better. We should dramatically increase our effort to develop controlled thermonuclear fusion which is without doubt the long term energy solution. But we shouldn’t demonize and ban fossil fuels for the wrong reasons. The evolution and transition to alternative fuels will happen naturally based on technology, economics, and our wisdom in applying resources properly. In the meantime we should concentrate on helping emerging economies scrub their power plant emissions of particulate pollution rather than worrying about atmospheric concentrations of trace gases like carbon dioxide.

Final Word

The scientific community has apparently become overwhelmed by the almost astounding amount of scientific effort from many different lines of inquiry that points to the conclusion that the globe is indeed warming. The cause of that warming, however, has not been extensively or critically examined by the scientific community. After all, it was an acknowledged assumption [Ref. (1)] of the founders of the IPCC that anthropogenic atmospheric carbon dioxide was the cause of global warming. Most researchers then simply confirmed the warming without examining the cause of that warming. As shown in this paper the assumption that CO₂ was the cause was not very solid to begin with and data assembled by the IPCC for other purposes, when properly interpreted, strongly suggests that CO₂ in not the cause.

Elizabeth Kolbert, in an effort to reinforce the thesis of anthropogenic global warming in her ‘Silent Spring’ like book, [Reference (5)], unintentionally said it all as she described a symposium in Iceland in 2004 with some 300 scientists present:

“Global warming is routinely described as a matter of scientific debate – a theory whose validity has yet to be demonstrated. The symposium’s opening session lasted for more than nine hours. During that time many speakers stressed the uncertainties that remain about global warming and its effects – on thermohaline circulation, on the distribution of vegetation, on the survival of cold-loving species, on the frequency of forest fires. But this sort of questioning, which is so basic to scientific discourse, never extended to the relationship between carbon dioxide and rising temperatures. The study’s executive summary stated, unequivocally, that human beings had become the ‘dominant factor’ influencing the climate.”

I rest my case.

Source material

Note: The writer has read literally hundreds of documents from the very scientific to the popular, to arrive at the thesis and to formulate the approach to its presentation and add to its fabric. Nearly everything used in the report including the three graphs came from reference 2. (the IPCC Fourth Assessment Report and its references). The other references below are listed because they are mentioned in the report.

References:

1. Intergovernmental Panel on Climate Change, Third Assessment Report: Climate Change 2001 (TAR) Working group 1: The Scientific Basis. (and references)
2. Intergovernmental Panel on Climate Change, Fourth Assessment Report: Climate Change 2007 (AR4) Working Group 1 Report: The Physical Science Basis (and references and secondary references)
3. J.T. Kiehl and Kevin E. Trenberth, Earth’s Global Mean Energy Budget, Bulletin of the American Meteorological Society, vol. 78, no. 2, Feb. 1997
4. Al Gore, AN INCONVENIENT TRUTH, Rodale Books, 2006
5. Elizabeth Kolbert, FIELD NOTES from a CATASTROPHE: Man, Nature, and Climate Change, Bloomsbury USA, 2006
6. Mike Lockwood and Claus Frohlich, Recent directed trends in solar climate
   forcings [etc], Proc. R. Soc. A (2008) 464, 1367-1385

posted November 10, 2009

Download this paper in pdf format

Abstract:
The overall problems for the energy-climate crisis are logistics and transportation (L&T), i.e., matching the locations, times, and amounts of supply to the location, times, and amounts of demand. The solution is to produce, at renewable and sustainable (R&S) source points, a chemical fuel that is practicable to collect, transport, store, and to distribute to demand regions. The most economic new R&S source now available is that of ideally located wind turbines. With current technology, electricity from wind turbines could be used to make enough ammonia-based fuel to relieve almost all our need for fossil fuel. In particular, this paper presents the fuel potential of guanidine, guanidine-urea alloys, and guanidine-alcohol solutions that could serve as carriers for ammonia or hydrogen. The potentials of ammonia and methanol are also discussed. If the hydrogen for any of these fuels is produced by electrolysis of saltwater, the resulting NaOH byproduct can remove CO₂ from the atmosphere and allow for climate recovery. Meanwhile, the HCl byproduct can be used in local mining operations to produce valuable commodities, and/or it can be sequestered as chlorides. The sequestered chlorides, the carbonates, and the mined pits can be used to geoengineer hydroelectric facilities.

Introduction

The Need for a Carbon-Negative Fuel

It is becoming clear to increasing numbers of people that the world cannot continue to rely on fossil fuels, not just because they are non-renewable and unsustainable, but because their use is driving catastrophic environmental changes with vicious feedback effects. For example, the melting of ice reduces albedo (a measure of reflectivity) from about 80% to 5% for exposed water or about 30% for exposed land so that more energy is absorbed, further increasing the heating. As permafrost melts in polar regions, more area is covered with water, further decreasing albedo and releasing methane from the methane-ice [1]. Because methane is a much stronger greenhouse gas than is CO₂ and because there is so much of it in the methane-ice, its large-scale release would cause extinction of many species. Also, seawater is being acidified by the excess CO₂ [2]. If ocean acidification continues to the point that sea creatures can no longer make their carbonate shells and bones, then not only will the global warming accelerate, but our food web will collapse.

The challenge considered here is how to avoid catastrophe as a consequence of a century and a half of development based on non-R&S energy sources [3]. The solution will require a new energy economy and infrastructure, but most of the technologies needed are now available and adequate; developments remaining seem quite manageable.

This massive change will cost about as much as the Iraq War plus the bailout of the Banking System (several trillion dollars), but this will be an investment with lasting value. The clear and present danger has not as yet motivated governments to drive the necessary change. However, because the energy economy is between 12% and 14% of GDP globally, there is an opportunity to make massive profits and create millions of jobs by engineering the solutions. Such economic incentives may bring about change where political reasoning has not.

Sources of R&S Energy

Available sources of solar, wave, and wind R&S energy each far exceed the amount now provided by fossil fuels. At this time wind is the technology that is being commercialized. Wind locations are rated by NASA and NREL as “poor, marginal, fair, good, very good, excellent, outstanding, or superb” depending upon average sustained wind velocity 50 m above ground [4]. Other factors that affect the quality of a site include wind turbulence, which produces torques on the rotor shaft that cause excessive wear, and the fraction of the time that wind velocity is within the range that the turbine can process. More than 27,000 MW of wind farms were constructed in 2008 [5], but almost all existing windfarms are at “marginal” to “good” locations, and are connected directly by a grid to customers willing to pay a high price for R&S electrical energy. It would be cheaper to generate wind electricity at a “superb” site and use it to make fuel there, so that neither a grid nor a grid connection is needed.

Even if it cost nothing to generate electrical energy sustainably, the problems of powering vehicles and of matching instantaneous local supply to instantaneous local demand would remain. The “intermittence problem” and the need to maintain a nearly constant grid voltage limit the direct contribution from wind to about 20% of our electrical energy, which is about 30% of total energy now derived from fossil fuels. This limit comes from the limited availability of gas turbines that can respond sufficiently rapidly to demand/supply fluctuations. Other electricity generators (coal, oil, nuclear, and hydroelectric) are all constrained, to one extent or another, by their ability to respond quickly.

To approach 100% replacement of fossil fuels, therefore, we will need to produce a fuel. When and where there is an excess of power on a grid, the fuel might be made there and then used at the same site when more power is needed. This is being explored as a means to strengthen electrical grids without new power-lines by building “Hydrogen Hubs,” although the fuel contemplated is ammonia [6]. Such opportunities are limited by the primary fuel supply.

Production of a practicable fuel will allow it to be produced cheaply at the “superb” wind locations, which are often the windward shores of islands at high latitudes, such as the Aleutians, Hebrides, Iceland, and Tierra-del-Fuego. These locations have strong wind with low turbulence much of the time, are very lightly populated so that land costs and siting objections are minimal, and permit the components to be delivered and erected from ships at minimal cost. Tropical storms and tornados do not reach high latitudes. Because fuel producing windfarms would be locally connected directly to DC electrolyzers, they would not need the expensive power electronic devices that are required for grid connections.

Consider briefly the cost of wind energy. The capital cost of a windfarm for a “fair” to “good” site is typically $1/W. The cost for a windfarm for a superb site will be less because the rotors and towers will be shorter for a given sized generator. The power varies as the cube of wind velocity (v³), so a rotor designed for 80 km/h is 1/8 as long as a rotor for 20 km/h. For the same ground clearance the tower is correspondingly shorter. The shorter rotor blades can be engineered to process a wider range of v. This combines with the more constant winds at “superb” sites to imply a capacity factor of about 80% compared with a factor of about 30% at “fair” sites. The capital cost of the fuel generating windfarm without grid connection electronics should be no more than $0.80/W. As the number of units manufactured increase greatly, the cost should drop further. While wind turbines at “good” sites with substantial wind turbulence are expected to last 20 years, turbines at “superb” sites without turbulence should last 40 years. At the end of its 40 year life the machine will need new bearings and rotors but the copper, magnets, steel, aluminum, concrete and other materials will be reused on site or recycled, so much of the initial value of a 5 MW turbine will remain. Still, investors will insist on recovering their investment in about 10 years, so we might take the capital cost to be $400,000/MWy. There are 8760 hours in a year. Thus a 5 MW turbine at a “superb” site should generate 35,040 MWh of electrical energy. Thus the capital cost of the energy is about $11.41/MWh. A leading manufacturer, Enercon, specifies 1 maintenance technician per ten 5 MW turbines so the maintenance cost should be about $250,000/50 MW = $5,000/MWy. This adds $0.71/MWh to the cost for a total of $12.12/MWh. Grid connected wind power is being sold (at a profit) for $25/MWh for an “outstanding” site in North Dakota and offered at $14/MWh at a “superb” site in Iceland; at a “fair” site the price is often $120/MWh.

Consider briefly the magnitude of the energy market. According to Wikipedia, the World average power consumption in 2008 was 15 terawatts (15×1012 W) and 80% to 90% of this came from fossil fuels, about 13 tW. (There are many good reasons to favor energy conservation to reduce this consumption level, but because the solution advocated here would remove CO₂ from the atmosphere and because this is an urgent need, it might be better to let all people buy as much R&S energy as they can afford. This also seems to be a political reality.) If the conversion of electrical energy to fuel is 54% efficient, which is what PureGeneration estimates, then 6 million 5 MW turbines are required to replace all fossil fuel. Their cost should come down with mass production, but at $4 million each, this would cost the World $24 trillion. 600,000 maintenance technicians would be permanently employed. The rule-of-thumb is that wind turbines should be spaced at 3 times the rotor diameter so as not to interfere with one-another. Although the rotors for the “superb” locations would be much shorter than those used at present sites, it might be prudent to space them at 200 m intervals so that there would be 25 turbines per km². Then the World’s windfarms would extend over 240,000 km². The superb sites of the Aleutians extend about 5,000 km, so if farms were 48 km wide, they could supply the World. (Of course, this would be neither practicable nor politically viable; there are too many other “superb” sites closer to important markets and belonging to other nations.)

The obvious fuel that can be produced from electrical energy is hydrogen from the electrolysis of water. Recent improvements in electrolyzers have dramatically reduced the cost of this [7] from a sales price of $2000/kW in 2003 to a low volume manufacturing cost of $164/kW in 2007. However, the physical properties of elemental hydrogen imply overwhelming L&T problems [8]. The hydrogen must therefore be reacted into some practicable compound.

There are evident two practicable families of fuel; one is methanol based [9] and the other is ammonia based [6, 10-13]. Methanol is a high octane liquid that can fuel air-cooled race car engines. It can also be converted to dimethyl ether, which is a high cetane diesel fuel. It can be used in direct methanol fuel cells or reformed to provide H₂ for H fuel cells. However, it is so toxic that major auto makers refuse to consider it for general use. Furthermore, methanol production from electrical energy, CO₂, and water still requires development, although this is a subject of ongoing research [7,9]. It is produced from wood and other biomaterials but these are not produced in sufficient amounts to replace all fossil fuel. (Note that a human diet of 2000 kcal/day equals 100 W and 1 metric horsepower is 750 W.) Methanol is now relatively expensive [13]. If a practicable method to produce methanol from electrical energy can be developed and its cost reduced, it would be possible to convert it to conventional hydrocarbon fuels that are less problematic and in common use [9].

In contrast, the technology to produce ammonia from electrical energy, air, and water is mature (electrolysis of water followed by the Haber-Bosch process).

Further, electrolysis of saltwater removes CO₂ from the atmosphere [14]:

4 H₂O + 2 NaCl → 2 H₂ + 2 NaOH + 2 HCl + O₂ (1)

The H₂ is then used for production of ammonia or methanol, and the NaOH is reacted with CO₂ to form baking soda or washing soda:

NaOH + CO₂ → NaHCO₃ (2)

or

2 NaOH + CO₂ → Na₂CO₃ + H₂O . (3)

There are markets for both commodities, but demand is a tiny fraction of the quantity that would be produced if enough hydrogen were produced to replace 100% of fossil fuels, whether by methanol-based or ammonia-based fuels. The remainder could be heaped in arid locations or covered to sequester the carbon dioxide and to sculpt landscapes. An inexpensive alternative would be to disperse the NaOH into seawater to reverse ocean acidification, but one would need to take care not to harm sea-life.

There is an $8 billion/y market for 40 million tonnes of HCl, which, if it were cheaper, might also capture part of the larger market for sulfuric acid. However, the amount of HCl produced replacing all fossil fuels would be orders of magnitude greater than present markets for hydrochloric and sulfuric acids combined. One would wish to avoid the expense of transporting the HCl any great distance from the sites where it is produced, presumably the lightly inhabited shores at high latitudes. Many of these sites have steep hills and mountains. It is suggested that the acid be used in the mining and processing of rock and ore near the generation sites to obtain valuable commodities. (An Icelandic concern has begun processing olivine using imported HCl at current prices [15].)

Simple ammonia has been used as a transportation fuel since at least 1933 [10], fueled Belgian buses during WW2 and the X-15 airplane [11,12]. It can be used in both Diesel and spark-ignited engines. It can fuel solid-oxide fuel cells and gas turbines (with some modification from natural gas designs [16]). It can be cracked or electrolyzed to provide hydrogen for hydrogen fuel cells [17]. It is now arguably the lowest cost option [13]. (Almost all ammonia is now made from foreign natural gas that has too severe L&T problems to come to market as methane. For US corn growers it is shipped as ammonia despite the substantial L&T expenses. For all other customers it is converted to urea or other ammonium compounds. With the recent advances in electrolyzers it now seems that it would be less expensive to produce ammonia in the US Corn-Belt from wind even at less than “excellent” sites [18]. Ref. 13 used a current price for ammonia from natural gas delivered to point of use.)

A persistent objection to the use of ammonia as fuel has been concern over the production of NOx, but several studies show that these concerns are overblown [19]. There are two sources of N that might result in NOx – the N₂ in the air and the N in the compound. Because NOx formation is endothermic and ammonia burns at a lower temperature than the fuels it would replace, NOx formation from the air is much less for ammonia than for fossil fuels. NOx formation from the N in ammonia is a problem for certain operating conditions; incomplete burning of ammonia is a bigger problem that has sometimes been mistaken for NOx formation. These problems can be managed by proper control of the engine [19] or eliminated by cracking or electrolyzing the ammonia and burning the hydrogen [17].

However, ammonia boils at -33°C at 1 bar so it must be pressured to 14 bar at room temperature to keep it in the liquid state. Its liquefaction requirements are similar to those of propane. Many special ships would need to be built to transport it to market from distant islands. It is highly toxic.

Solution

Ammonia can be converted to relatively safe and convenient solids for transport, storage, and distribution and then converted back to ammonia at the time of use. Two options have been advanced; one is urea based [20,21] and the other is guanidine based [22,23].

More than 100 million tonnes per year of urea (CON₂ H₄) are produced commercially by combining two units of ammonia with one of CO₂ and extracting one unit of water. Urea is a non-flammable, non-toxic solid with a melting point of 133°C. It can be converted back to ammonia by adding hot water (178 kJ/mole), which may come from oxidation of 1/3 of the ammonia, with a catalyst. The ammonia releases 809 kJ per mole of urea when oxidized. Thus, its use as a sustainable and renewable fuel is being advocated [21].

Problems with the use of urea as fuel include: a) its energy density and specific energy are lower than the Freedom Car benchmarks; b) while the solid phase is convenient for storage and transportation, one would want the molten phase for plumbing within an engine and 133°C is inconveniently high; and c) one might want to liquefy it by combining it with liquid, but its solubility is poor in ethanol and limited in water.

Guanidine (CN₃H₅) can be made by combining three units of ammonia with one unit of CO₂ and extracting two units of water [24, 25]. Guanidine is a highly alkaline and hydroscopic but non-flammable and non-carcinogenic solid with a melting point of +50°C.

Shaver Process to make guanidine [25].

Guanidine can be converted back to ammonia by addition of 4/9 of the water from the oxidation of the ammonia and less heat than required for urea. The first step of this conversion is exothermic, which is convenient for cold starting. Its energy density and specific energy substantially exceed the Freedom Car benchmarks [23]. Its melting point is convenient for plumbing engines. It is completely soluble in ethanol and in water. It can be alloyed with urea. It can be coated with urea. Up through the 1960s it was produced on an industrial scale, particularly as a precursor for melamine. Since melamine has gone out of fashion, its production has declined.

First step of guanidine to ammonia conversion.

The production of 1 tonne of guanidine by electrolysis requires [23] 10 MWh of electricity. The 13 tW World rate of (fossil) fuel consumption would require 2.1×10¹⁰ t/y of guanidine for 100% replacement at 54% efficiency. A fixed cost estimated to be $43 must be added to the cost of energy. If the electricity costs $14/MWh, the total cost estimate is $183/t. 1 t of guanidine provides the equivalent of 148 gallons of gasoline (148 GGE). Thus, the cost estimate for “superb” sites is $1.24 / GGE. If the cost of electricity were $25/MWh, as currently in North Dakota, the cost would be $1.98 / GGE.

Consider the cost of transport to market. Spot rental rates for bulk carrier ships fluctuate wildly with supply and demand but $10,000/d for a 50,000 t ship that can sail at 20 knots is reasonable. Suppose the ship spends 1 day loading, 1 day unloading, and 10 days sailing each way. Thus it can carry 50,000 t 8,800 km for $240,000, assuming it sails back with no cargo. This adds $4.80/t or $0.03/GGE to the cost of the fuel. Transportation of 2.1×10¹⁰ t/y in this way would require 4.2×10⁵ voyages/y. If each ship makes 15 voyages per year, 2,800 ships are required. It may be practicable to convert existing oil-tankers to carry R&S fuels and thus to reduce transportation costs.

Should methanol, or urea, or guanidine be made with H2 from freshwater, CO₂ from the atmosphere, and wind energy, then the fuel would be carbon neutral. Because the greenhouse gas level is now past the point that catastrophic climate change has begun, carbon neutrality is not enough; we must reduce the level of CO₂ to that of the 19th century. As noted, this can be done by electrolysis of saltwater to provide the H2 with co-production of NaOH.

Transportation of HCl is so expensive that it is now generally made by saltwater electrolysis at sites where it will be used, so the “Hydrogen Hub” concept might serve present chlorine markets by electrolyzing saltwater (and by replacing ammonia storage in urban areas with guanidine storage).

The islands at high latitudes that are the best sites for the wind farms often have basaltic mountains and sometimes have exposed olivine on slopes. Many also have substantial amounts of ores but may not be economic to mine if materials such as acids need to be shipped in. HCl produced nearby as a byproduct of fuel production should be less expensive. The mining process could sculpt out a succession of pits connected by trenches on these slopes as the minerals in the rocks are mined to produce valuable commodities. The material that is mined out and processed but not exported as an economic commodity could be heaped around the pits and trenches. This material would sequester chlorine from the conversion of various oxides to chlorides by the HCl. To this would be added the carbonates that sequester the CO₂ from the atmosphere. This would gradually produce hydroelectric facilities that would use the abundant precipitation at many of these sites.

The figure below illustrates a process for olivine that extends Gunnarsson’s process for the production of fume silica [15,26], which has a surface to mass ratio of 40 to 400 m2/gm. The HCl first converts olivine, [Mg,Fe]₂SiO₄ , to SiO₂ and H₂O, and to MgCl₂ and FeCl₂, which are not suitable for sequestration. The MgCl₂ and FeCl₂ can be reacted with the Na₂CO₃ to form MgCO₃ and FeCO₃, which are good for sequestration, and NaCl. A portion, adjusted to market conditions, of the chlorides can instead be processed to produce iron ore, electrolytic iron, magnesium metal, magnesium carbonate hydroxide, MgO, and Si using some of the electrical energy generated at these sites. Large amounts of MgO can be used to replace CaO in the making of cement, which would reduce a major contributor of CO₂ to the atmosphere [27]. It would also produce better cement that is less damaged by salt.

Processing of basalt could provide Al, K, and Ti commodities, as well as Fe, Mg, and Si.

However, the replacement of all fossil fuel would produce amounts of these oxides that would exceed their markets. The excess Al₂O₃, MgO, and SiO₂ might be used as aggregate to provide high albedo concrete for civil structures and pavements. Increasing urban albedo to about 80% would dramatically reduce the need for air conditioning and slow global warming. As noted above, transporting these very high albedo materials by sea would cost only about $4.80 /t.

The mining option and geoengineering would provide for future hydroelectric power. Initially this would provide back-up power for the electrolyzers, but eventually enough hydroelectric power might be produced that the wind turbines would no longer be needed.

Conclusions

Renewable and sustainable electrical energy suffers from problems of logistics and transportation. These problems could be solved by using the electricity to produce an easily stored and transported chemical fuel. This paper argues that:

• Wind energy generated on high latitudes shores is the most practicable way to power fuel production.
• Including electrolysis of saltwater as a step in fuel production removes CO₂ from the atmosphere, reversing atmospheric effects of past fossil fuel combustion. The HCl byproduct of electrolysis can be used for local mining and to create future hydroelectric facilities.
• Methanol would provide fine fuel but needs breakthrough for production from electricity.
• Ammonia is fine fuel but has problems of logistics and transportation.
• Storing ammonia in the form of pure guanidine and mixes of guanidine, urea, and alcohol solve the L&T problems of ammonia.
• NOx concerns with ammonia, urea, and guanidine can be eliminated by electrolysis or cracking to hydrogen, or by proper control of engines.

Notes

The author is one of the founders and board members of PureGeneration; he is a Professor Emeritus of Electrical Engineering at Oregon State U. and was formerly at IBM Research, Bell Laboratories, and US Naval Research Laboratory. PureGeneration is a for-profit UK corporation concentrating on the guanidine-based fuels, the sequestration of CO₂, and the use of HCl for mining options discussed herein.

[1] Cf., e.g. http://www.independent.co.uk/environment/climate-change/exclusive-the-methane-time-bomb-938932.html or http://www.sciencedaily.com/releases/2008/05/080528140255.htm and http://en.wikipedia.org/wiki/Methane_clathrate and therein.

[2] Cf., e.g., http://www.ocean-acidification.net/; http://en.wikipedia.org/wiki/Ocean_acidification and therein.

[3] Cf., e.g., Paul Brown, Notes from a Dying Planet, 2004-2006 (iUniverse, Bloomington, 2006); Tim Flannery The Weather Makers (Atlantic Monthly Press, New York, 2006).

[4] Cf., e.g., http://www.windpoweringamerica.gov/wind_maps.asp .

[5] http://en.wikipedia.org/wiki/Wind_power.

[6] Cf., e.g., Jack Robertson and Preston Michie at http://www.hydrogenhub.org .

[7] Cf., e.g., http://www.itm-power.com/press/1.pdf ; http://www.itm-power.com .

[8] J. J. Romm, The Hype about Hydrogen (Island Press, Washington, DC 2004).

[9] G. A. Olah et al., Beyond Oil and Gas, The Methanol Economy (Wiley-VCH, Weinheim, 2006).

[10] Worth a try, Research and Development in Norsk Hydro through 90 years ( Norsk Hydro, Oslo 1997) p. 125.

[11] E. Kroch “Ammonia – a fuel for motor buses”, J. Inst. Petroleum 31, 213-223 (1945).

[12] Cf. http://www.energy.iastate.edu/Renewable/ammonia/ammonia.htm and
http://www.ammoniafuelnetwork.org/.

[13] C. Zamfirescu and I. Dincer, “Using ammonia as a sustainable fuel” J. Power Sources 185 459-465 (2008).

[14] S. Mazrou, H. Kerdjoudj, A. T. Cherif, and J. Moleenat, “Sodium hydroxide and hydrochloric acid generation from sodium chloride and rock salt by electro-electrodialysis “ J. Appl. Electrochem. 27, 558-567 (1997).

[15] G. Gunnarsson, “Process for the production of silica from olivine” in PCT/ISO3/00035 Ser. # 536194 (2003); US Patent Application 20060051279 (2006).

[16] William E. Lear at http://www.energy.iastate.edu/Renewable/ammonia/ammonia/2007/Lear_NH3.pdf .

[17] Cf., e.g., Gerardine G. Botte, “Electrochemical Method for Providing Hydrogen Using Ammonia and Ethanol” US Patent Application 20090050489 (2009).

[18] Steve Gruhn and Barry Sackett in http://www.energy.iastate.edu/Renewable/ammonia/ammonia/2008/Gruhn_2008.pdf .

[19] Cf., e.g., for spark ignited engines running on ammonia within emission limits in California, Ted Hollinger and Don Vanderbrook at http://www.energy.iastate.edu/Renewable/ammonia/ammonia/2007/HEC.pdf ; Ted Hollinger at http://www.energy.iastate.edu/Renewable/ammonia/ammonia/2008/Hollinger_2008.pdf ; for Diesels see Aaron Reiter and Song-Charng Kong at http://www.energy.iastate.edu/Renewable/ammonia/ammonia/2007/Kong_NH3.pdf .

[20] M. G. Del Duca, “Enzyme activated biochemical battery” US Patent 3,403, 053 (1968); M. G. Del Duca et al., “Direct and indirect bioelectrochemical energy conversion systems” Dev. Indust. Microbiology 4 , 81-91 (1963).

[21] S. C. Amendola, “Urea based composition and system for same” US Patent 7,140,187 (2006).

[22] R. K. Graupner, J. D. Hultine, and J. A. Van Vechten, “Guanidine based fuel system and method of operating a combustion system” WIPO 2005/108289 (2005), US Patent Pub. 20080307784 (2008); “Guanidine based composition and system for same” US Patent Pub. 20080286165 (2008).

[23] R. K. Graupner “Guanidine – Safe, Clean, and Flexible” http://www.energy.iastate.edu/Renewable/ammonia/ammonia/2006/OregonSustainableEnergy.pdf

[24] The Chemistry of Guanidine, Cyanamid’s Nitrogen Chemicals Digest Vol. 4, (American Cyanamid, New York, 1950).

[25] K. J. Shaver “Guanidine or Melamine Process” US Patent 3,108,999 (1963).

[26] Cf. R. K. Graupner, J. A. Van Vechten, and J. D. Hultine, “Fuel synthesis method” published international patent application WO2009/05688 (2009).

[27] http://tec-concrete.com/simple.eco-cement.php .

I’m very curious to hear what you all think of the feature. Has anybody accessed and read the full story? Is the online feature useful on its own? I know some of our white paper authors will take issue with the conclusions! In any case, comments are welcome!

Saurabh H. Mehta, Centre for Energy Environment and Education (CEEE), India. email: smh048 (at) gmail.com

posted November 6, 2009

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Abstract: Worldwide growth of economy and population has caused an immense increase in demand for energy. Furthermore, energy prices have always been volatile. These trends are expected to continue and even worsen in coming years. These trends create both pressure and opportunities in the steel industry to seek new technologies for conservation, substitution of fuels, and ultimately the development of new steelmaking processes which are environmentally friendly. Such measures are intended to reduce the steel industry’s reliance on energy sources, as well as the volume of greenhouse gases it introduces to the environment. This paper discusses a technology to improve the energy efficiency of the Electric Arc Furnace (EAF) in the steelmaking process by utilizing the heat of the waste gases from the EAF to generate steam that can be used in other applications within the steel plant.

Introduction

Currently steel industries are the largest energy consuming sector in the world, accounting for 15% of world’s industrial energy consumption. Steel industries all across the globe are highly energy intensive. Of the total cost of producing steel, 20% is spent on energy. The increasing cost of energy and even its current and future availability shows the need to refocus attention on energy conservation in steel production.

India’s Scenario

India is a developing country and thus has a very high future demand for steel. Different projections have been made regarding the proposed capacity by 2020.

In India, Steel is the second largest sector in greenhouse gas emissions, second only to the power sector. Energy accounts for 30-35% of total production cost of steel in India—worse than the global figure of 20%. A technology such as the one discussed in this paper should be deployed in steel plants of India to save energy and reduce CO₂ emissions. Development and installation of this system in newly constructed steel plants will not be very costly.

Energy & Steel Production

The energy employed directly by the steel industry ultimately results in the production of final steel products, various by-products, and process losses in the form of heat (Figure 1).

Figure 1. Steel industry inputs and outputs.

All the sources of energy used in steel production are factors in the generation of carbon dioxide to various degrees on account of:

• Electricity consumption
• Combustion of fossil fuels for energy (heat)
• Use of Coal and Lime as feedstock

We need approaches to lower energy use in steel production. Thus there is a need to develop:

• Technologies that can take advantage of the energy currently lost in existing processes.
• Recovering and applying wasted heat at high temperature.

There are significant energy savings opportunities in the steel production process which are yet untapped. Steel industries already produce fuels in the form of by-products like fume gases. Gas reforming technologies utilizing the sensible heat contained in steelmaking off-gases could yield substitute fuels for use in steel plants. A high potential for energy conservation lies in energy recovery.

Introduction to Steel Plant

Units of the steel plant that are relevant to the proposed technology are explained in detail below. A flow diagram of the steel production process is available at this link.

Electric Arc Furnace
Steel is an alloy, with iron as the base component. The other important elements are carbon, silicon, manganese, chromium, aluminium, phosphorus, molybdenum, and boron. Direct reduced iron (DRI) and sponge iron (SI) is sometimes used with scrap to help maintain desired chemistry of the steel. Pig iron is added to the above mixture (having 4% carbon), which finally forms the charge which is added to the electric arc furnace along with coke and flux (mixture of lime and dolomite). The furnace is heated for scrap melting at a temperature of 3000°C using graphite electrodes and pressurised oxygen. The slag formed is taken out; the flame is sucked out continuously using Fume extraction system (FES). The molten metal is then tapped to the ladle furnace.

Ladle Refining Furnace
A ladle furnace is used for precision control of chemistry. The ferroalloys of elements such as manganese, silicon, chromium, nickel etc are added to the furnace and the ladle furnace is heated using graphite electrodes. Argon used as a purging gas and is purged to the ladle furnace from the bottom for proper mixing of the molten metal.

Vacuum Degassing Furnace
The vacuum degassing system is used in the final refining step to remove hydrogen, oxygen, sulphur and/or carbon. These achieve low sulphur levels, remove carbon, and improve floatation of oxide inclusions, allowing them to be entrained in the slag. This results in the highest quality steel. A VD furnace pays for itself in 2 years, and VD systems are becoming popular in steel production. The vacuum in the furnace is mostly produced by an all-steam ejector pumping system, or a combination of steam ejectors and a mechanical pump system. For this reason, a steam boiler is installed near to the VD furnace.

Fume Extraction System (FES)
The FES is typically utilized in combination with the EAF & LRF to capture airborne particulate emissions and to exhaust certain flammable and hazardous gases that evolve during furnace operation. In particular, gases such as CO and H₂ are generated during the melting and refining process, and must be properly vented and treated by the FES. A negative pressure is generated within the FES, via an induced draft (ID) fan, to draw fumes from the EAF into the FES for treatment (For an illustration, see reference 10, page 7.) The ID fan pulls fumes through a bag house including filters, and then exhausts the filtered gases into the atmosphere. Since the fumes exit the EAF at a temperature close to 1250°C, the fumes are typically cooled prior to entering the bag house at temperature of <130°C using a forced draft cooling system. In this cooling system, cold water from a cooling tower is pumped into ducts of the FES, which absorbs heat from the fumes. This hot water from the ducts is then pumped back to the cooling tower. This is done to bring down the temperature of the fumes before they are disposed off to atmosphere (Figure 2).

Figure 2. In the fume extraction system, energy (heat) is lost to the atmosphere rather than recaptured and utilized.

A large amount of energy is wasted in the form of fumes from the EAF and in the unavoidable heating of the furnace apparatus (Figure 3). Thus, it makes sense to extract and use heat from the fume gases of the FES and from the overheated furnace apparatus. The recovery of heat does not mean simply cooling the furnace to prevent overheating of structural parts or for other operational purposes, but rather, it means recovering the useful heat that would otherwise be lost.

Figure 3. Similar heat loss also occurs in the EAF.

Potential for Energy Conservation

• For every ton of steel melted in EAF about 4*10⁵ kJ of energy is wasted, in the form of fumes and in heating up of the furnace & its apparatus.
• Vacuum degassing is done for high-level purification of stainless steel. This requires large quantity of superheated steam (230°C) in every cycle, for which a boiler is installed in the VD system.
• In the boiler of the VD system, for purifying one ton of stainless steel:
  Furnace oil consumption = 13 L.
  Amount of water converted into steam = 100 kg.
  Energy required to heat water from 20°C to steam at 230°C = energy required in boiler = 3*10⁵ kJ.

Background of the Technology

The proposed technology relates to a method and an apparatus for recovering waste heat from EAF whose exhaust gases have high dust content. The recovery of waste heat has been very difficult with conventional techniques. This paper improves and expands upon similar technology that has already been proposed and patented (see references 9 and 10.)

Various devices have been proposed for recovering waste heat from EAF. In these methods, the internal pressure of the recovery device is kept higher than atmospheric pressure in order to increase the quantity of useful heat recovered. But proper maintenance and management for safe operation is required. Another difficulty is that the dust contained in exhaust gases is generally very liable to adhere to the structure and because this dust has poor heat conductivity, the size of the heat recovery area must be enlarged, thereby resulting in increased size of the apparatus as a whole.

The present technology is free from the aforementioned disadvantages, and is capable of recovering useful heat without reducing the production capacity of the EAF itself.

Working of the System

Water is pumped through an ion exchanger where impurities are removed to prevent water hardening. This purified water is then stored in feed water tank.

The heat recovery system takes place in two parts:

1. Primary heat recovery section
2. Secondary heat recovery section, as shown.

The water from the feed water tank is fed into the primary heat recovery section by a pumping system and flow controller. Here the water cools the overheating apparatus of the electric arc furnace. The heat emanating from the EAF components is recovered by controlling the temperature of the cooling liquid circulating through the furnace apparatus in such a way that the maximum temperature of the coolant remains below its boiling point, under normal atmospheric pressure.

In the secondary heat recovery section, a stream of dust-laden gas leaves the EAF under the action of the induced draft fan. This stream of gas is passed through the internal tubes of the heat exchanger, which are made of heat-proof steel and have a circular shape so as to minimize adhesion of dust and to allow easy removal of dust if it does accumulate.

Simultaneously a stream of hot water is flowed by a pump, as a heat exchange medium, along the outer side (shell side) of the heat exchanger. The water is heated in the heat exchanger to a high temperature and is converted into steam. This steam is then collected in a steam drum. The stream of EAF discharge gas is lowered to a temperature level at which the filter can be operated effectively. The discharged fume gases are filtered and finally released to the atmosphere through the chimney, having less energy than before.

The steam from the steam drum and hot water from the feed water tank are accumulated in a steam accumulator. A steam accumulator is an insulated pressure tank containing hot water and steam under pressure. It is a type of energy storage device which is used to smooth out peaks and troughs in demand for steam.

This steam generated can be used for driving vacuum pumps at the VD plant, or for driving a single strand steam turbine to generate electricity (For an illustration, see reference 10, page 11). Both ways a high saving of fossil fuel can be achieved and the carbon emission can be reduced significantly.

Calculations

For every ton of steel produced-
120-150 kWh of heat that can be recovered from EAF.
Using the above mentioned heat recovery system, with a heat exchanger of efficiency close to 55%, 75 kWh can be utilized for steam generation.

For Use in VD Boiler
Energy requirement at the vacuum degassing boiler is 85kWh.
Available energy recovered above = 90% of 75 kWh= 68 kWh
This is 80% of total energy requirement at the VD boiler.

For Producing Electricity
Some steel plants use VD system full time, some of them use it sparingly and some don’t use it at all. Though it’s more efficient to use the generated steam in a VD boiler, it can also be used to run a steam turbine to produce electricity when a VD is not in use. The 75kWh of recovered energy could power a turbine and produce electricity with an overall efficiency of 50%, yielding approximately 40 kWh of electric energy.

Monetary Savings

VD Boiler
With an efficiency of 55% in VD boiler,
Calorific value of oil used- 10,000 Kcal/kg =12kWh/kg
For 68 kWh energy saved, the amount of fuel saved = 68kWh/(0.55*12kWh/kg)
= 10.5 kg

So, for every ton of steel produced 10.5 kg equivalent of furnace oil energy is saved. This otherwise would have cost Rs.350 ($7.6).

Power Generation
For every ton of steel produced, 40 kWh of electrical energy will be produced. This otherwise would have cost Rs.240 ($5.2).

For a steel plant with an annual production capacity of 1 million tons, and which uses VD boiler 50% of the time, the total annual monetary saving will be:
{(350 +240)/2}* 1000,000 = Rs.30crore ($6.5 million).

In India the annual production capacity is expected to go above 200 million ton by 2020, thus incorporating such waste heat recovery in steel plants can save a lot of money.

Advantages

1. The dependency on fossil fuel will decline.

2. Overall carbon emission will be reduced.
3. Due to reduction in the combustion rate of the furnace of boiler, the boiler will be more efficient and actual fuel savings will be greater than that theoretically calculated.
4. The heat extraction and simultaneous utilization shows that both the cooling towers can be easily avoided as the heat diffused by them to the atmosphere is now being utilized as energy in the boiler.
5. By preventing the furnace from overheating, this process also improves the overall life of the furnace and its equipment.

Weaknesses

Even with the proposed recovery system, much energy is lost in the recovery process. Research should therefore focus on maximum recovery from these gases.

Conclusion

Changing the energy footprint of the steel industry is a daunting task, but the rewards could be large. Retrofitting the above discussed system in an already running plant can be difficult, and would impede the working of the plant during installation. But for a steel plant that is to be commissioned, this system can be installed with minimum difficulties and great advantages.

At this juncture, when demand for steel in India is growing rapidly to meet the domestic and global demand, energy efficiency is the only method to counteract the associated impacts.
However, lack of financing capabilities as well as lack of incentives impedes the implementation of such systems.

Sectoral policies should be developed to promote such incentives, and policy strategy should be a mix of regulatory and price based incentives. There is an immense potential for energy recovery projects in the steel sector.

Bibliography

1. J.A.T. Jones, B. Bowman, and P.A. Lefrank, Electric Furnace Steelmaking, in The Making, Shaping and Treating of Steel, 525–660. R. J. Fruehan, Editor. 1998, The AISE Steel Foundation: Pittsburgh.
2. G. D. Rai, Non Conventional Energy Sources, 17th Edition. 2006, Khanna Publishers: New Dehli.
3. M. V. Deshpande, Elements of Electric Power Station Design. Wheeler Publishing Co.
4. R. K. Shah, Fundamentals of Heat Exchanger Design. 2003, John Wiley and Sons.
5. B. G. A. Skrotzki & W. A. Vopat, Power Station Engineering and Economy, 22nd Edition. 2002, Tata McGraw Hill.
6. American Iron and Steel Institute, Saving One Barrel of Oil per Ton: A New Roadmap for Transformation of Steelmaking Process. 2005.
7. Databases from MARMAGOA STEEL LIMITED (MSL), Goa.
8. S. Banerjee, “Process for making steel,” US Patent 6424671, July 23, 2002.
9. K. H. Oribe, M. Watanabe, and T. Machida, “Electric furnace waste heat recovery method and apparatus,” US Patent 4099019, July 4, 1978.
10. H. Ester (SMS Siemag), “Energy recovery technology for EAFs,” presented at the International Convention on Clean, Green, and Sustainable Technologies in Iron and Steelmaking, Bhubaneswar, India, July 15-17, 2009.
11. K. K. Singhal (Steel Authority of India, Ltd.) “Energy efficiency in steel industry & Clean Development Mechanism,” presented at the International Convention on Clean, Green, and Sustainable Technologies in Iron and Steelmaking, Bhubaneswar, India, July 15-17, 2009.
12. F. H. Dethloff, “Process and apparatus for treatment of waste gases,” US patent 4176019, November 27, 1979.
13. D. Halliday, R. Resnick, and J. Walker, Fundamentals of Physics. Wiley.
14. Ministry of Steel (India,) National Steel Policy. 2005.

Dr. Solomon Zaromb, Zaromb Research Corp., Burr Ridge, IL 60527, email address: zarombs (at) cs.com
Dr. Joseph R. Stetter, Professor of Chemistry, Illinois Institute of Technology

posted November 2, 2009

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Abstract: Aluminum as a safe and compact means of energy storage and hydrogen generation is obtainable immediately from presently unutilized waste and in future years from an emissions-free process. Salvageable aluminum waste should be highly advantageous for stationary power backups, for electric motor boats, and for economizing fuel by injecting hydrogen into the intake manifold of internal combustion engines, but there is not enough of it at present for powering a sufficient number of electric automobiles to seriously impact global warming. This paper is therefore restricted to the above three immediately realizable applications, keeping in mind that it should eventually be possible to produce enough inexpensive aluminum without adding CO₂ to the atmosphere by restricting the power supplied to its production plants to carbon-free sources, sequestering plant emissions, and using an inert anode-wetted cathode process.

Introduction

Although more than 50 percent of America’s aluminum is recycled, about “2 million tons of aluminum cans, containers and other types of packaging are thrown away each year” (1).

Besides uncollected aluminum cans and other packaging (foils, wrappings, and various containers), there are also large amounts of machine shop filings, and other scrap winding up in landfills instead of serving as fuel for backup power in homes, hospitals, and other vital facilities.

During the Katrina disaster, the disruption of cellular phone communications prevented many victims from even informing whatever helpers may have been available of their critical situation. Had the cellular communication towers been powered by a system that would be immune to flooding, many lives might have been saved.

Therefore, our first application for hydrogen from aluminum waste is back-up power for homes, hospitals, and other indispensable facilities.

Although formation of hydrogen by the reaction of aluminum with water has been known for more than sixty years (2), its utilization for the generation of heat and electricity from aluminum, especially from waste, was not proposed until some 30-40 years ago (3, 4). Nevertheless, among the various alternative energy sources currently under consideration, aluminum is rarely mentioned, probably because of wide disappointment with the intense and expensive attempts to develop an Al-air electric vehicle battery during the 1970’s and 1980’s (5, 6). Besides the problems encountered in those efforts (7), we found in our own work the overshadowing tendencies of:

1. the air cathodes in the Al-air system to get clogged by Al(OH)₃; and
2. an uncontrollable corrosion reaction to occur in the presence of some impurities.

The clogging problem disappears and corrosion is what we want when hydrogen is generated by dissolution of Al in alkaline solution according to the reaction:

2Al + 3H₂O → 2Al(OH)₃ + 3H₂                [1]

yielding 1 g H₂ per 9 g Al + 9 g H₂O. The energy dissipated in Reaction 1 may be partly recovered by feeding the generated H₂ to a fuel cell. Assuming 100% current efficiency and a fuel cell output of 0.7 volt, the energy yield from Reaction 1 amounts to 2.1 kWh/kg of aluminum (see Note B). An obvious reason to consider aluminum and water for H₂ generation is the ease and safety with which these reagents can be transported, stored, and used.

The high energy density of aluminum and its non-flammability render it the material of choice for safely storing a large supply of energy within a modest volume. An 8-m³ half-full bin could store 10,800 kg of aluminum in form of comminuted chips, pellets or granules, which could yield about 23,000 kWh when reacted with water so as to generate hydrogen for a fuel cell, enough to supply 100 kWh continuously for nearly 10 days. Since a system such as outlined in Fig. 1 could be built to withstand flooding, it could assure cellular phone communications throughout the duration of Katrina-like disasters with possible savings of many lives and maintenance of the functionality of backed up homes and facilities.

Figure 1. Generation of hydrogen from aluminum waste.

Although considerable progress has been made in recent years in developing commercialized Al-air batteries (8), we know of only one recent approach to the generation of hydrogen by our above Reaction 1, and that approach uses a not inexpensive alloy of aluminum and gallium (9). Similarly, the cost of the aluminum used in the recently reported batteries may adversely affect their competitiveness, especially for the motor vehicle applications for which they are mainly promoted.

Other attractive applications for the use of Al waste as per Reaction 1 are:

1. For electric boat propulsion; and
2. For injection of hydrogen into the intake manifold of an internal combustion engine (ICE).

The electric boat application is obviously highly attractive because the availability of plentiful water doubles the effective energy density of the power source. The injection of hydrogen into the ICE is discussed in a following section.

This paper is regrettably inapplicable to the propulsion of ground-based electric vehicles because the amount of aluminum presently wasted could only supply a small fraction of the potential demand for it. Conceivably, as the uses of aluminum waste become popularized, a preference for products packaged in aluminum rather than other metals, paper, plastics or glass may eventually result in major increases in disposable aluminum waste. It is also possible that major cost and energy savings may be achieved by a process using inert anodes and wetted cathodes for the production of aluminum [11 kWh/kg versus the current 15 kWh/kg] and this process may also be substantially free of emissions of greenhouse gases, especially carbon dioxide and fluorocarbons (10). A major obstacle to the actual construction and operation of inert anode smelting plants may be a concern as to whether the products of this process can meet the specifications of commercial grade aluminum. However, for hydrogen generation purposes, any impurities introduced into aluminum shot (grains, beads or pellets) from the inert anodes should not interfere in any way with the aluminum-water reaction. Therefore, the inert anode process may be fully functional at its present state of development for the production of aluminum beads or granules intended solely for hydrogen generation purposes. However, for the near term, we must restrict ourselves to those applications which appear to be immediately feasible.

Solutions

The hydrogen generator assembly of Fig. 1 includes a reaction chamber, wherein aluminum fed from a hopper is reacted with water to yield its hydroxide, hydrogen, and heat, with the rate of this process being automatically regulated by a servo-mechanism which adjusts the aluminum content within the chamber according to hydrogen demand. The aqueous solution is usually strongly acidic or strongly alkaline, but alkaline electrolytes containing 3 to 10 moles/liter of NaOH or KOH are preferred. The heat generated in the chamber may be dissipated by external heat fins or carried away by a circulating fluid and used for space heating or other applications. The aluminum hydroxide reaction product is removed from the system and may be shipped for substantial refunds to producers of fresh aluminum or “of aluminum chemicals, such as aluminum sulfide, sodium aluminate, aluminum fluoride, and aluminum chloride hexahydrate… petroleum catalysts, plastic and rubber goods, paper, glass and vitreous enamel, adhesives, varnishes, and toothpastes” (11).

To provide a failsafe back-up power system, the assembly is preferably sealed and made of rugged materials to render it resistant to flooding, fire, and other natural or manmade disasters. Besides being contained within a water-proof enclosure for the critical components of the system and its external wiring, the fuel cell of Fig. 1 should be placed as high as practicable with its air intake shielded from water droplets by a water-repelling porous Teflon filter. As a precaution against the flood level reaching so high as to obstruct air from passing through that filter, a compressed air or oxygen tank could be set up within the shielded enclosure to provide the needed oxygen for the duration of the obstruction.

Since back-up power is usually needed only in cases of electricity failures or other special circumstances, the aluminum waste that is to be fed to the hopper of Fig. 1 can be accumulated gradually by its users dropping it into a storage unit each time they would otherwise have disposed of it into a garbage bin. This would not only provide a cost-free and safe fuel, but could also yield some revenue from sales of the hydroxide product to aluminum chemicals producers. Since the amount of hydroxide generated from back-up power can not be expected to flood the chemicals market, its refund value may be substantial.

In Fig. 2, the hydrogen is fed to the intake manifold of an ICE, thus replacing a commercially available hydrogen fuel injection (HFI) system which generates hydrogen by electrolysis of water, such as those offered by the CHEC (Canadian Hydrogen Energy Company, LTD), or by the Canadian Eagle Research Company’s HyZor On-Board Electrolyzer. Based on data provided for one commercial HFI system, we estimate that at least 7 gallons of combustible fuel (gasoline, Diesel, propane, natural gas, or fuel blends) could be saved from the injection of hydrogen generated by 1 kg of aluminum over a vehicle travel distance of about 2,000 km. While this could be obtained from presently wasted aluminum for about 30% of all household vehicles, the ample supply of more expensive aluminum could still yield a seven-fold return for all vehicle owners even at a price of $3/kg.

Figure 2. Injection of generated hydrogen into intake manifold of internal combustion engine.

The injection of aluminum-derived hydrogen into the intake manifold of an ICE can be effectuated and controlled in the same way as is practiced with presently offered HFI systems whose hydrogen is derived from water electrolysis. The advantage of the aluminum-derived hydrogen is that its generation does not consume electrical power if the aluminum is obtained from waste.

In Figs. 1 and 2, disposable aluminum products are first ground down or cut up by a suitable cutting, grinding or other comminuting device (not shown) into particles sufficiently small to be attacked by an aqueous alkaline electrolyte in their reactor. Apparatus for grinding or cutting up aluminum objects may include a lathe, milling machine, grinder, and/or a guillotine-type device, or a suitable combination of the operating principles of one or more such devices, all of which are well known to persons skilled in the mechanical arts. Alternatively, some of the newest processes for producing inexpensive aluminum may eventually be adapted to yield aluminum in form of small particles, also called “aluminum shot”.

Each of the three above-outlined applications appears to be within the present state of the art and its realization may require mainly financial investments for development work including detailed design and construction of a working prototype, thorough testing and evaluation of the first prototype, and implementation of any needed corrections and improvements, followed by large-quantity production and commercialization.

Conclusions

In summary, we presented three potentially advantageous uses of hydrogen generated from aluminum waste. These appear to be immediately realizable within the present state of the art making use primarily of inexpensive aluminum from presently unsalvaged waste. Each of these will result in significant energy savings at little or no cost to their users and none of them needs to add any direct or indirect burden to global warming.

Notes

A. The disclosures of this White Paper are covered by a pending patent.

B. 0.7(volt) x 97,000(coulombs/Faraday) x 1(Faraday/9 g Al) ≈ 7,500 joules/g ≈
    7.5 x 10⁶(joules/kg)/3.6 x 10⁶(joules/kWh) ≈ 2.1 kWh/kg

References

1. Anonymous, Aluminum Recycling, DRLP FACT SHEETS, Ohio Department of Natural Resources, Columbus, Ohio (2005)
2. W. H. Latimer and J. H. Hildebrand, Reference Book of Inorganic Chemistry, pp. 90-93 and 474-478, Macmillan Company, New York (1940)
3. I. E. Smith, “Hydrogen generation by means of the aluminum/water reaction,” J. Hydronautics, 6(2):106-109 (1972)
4. S. Zaromb, C. N. Cochran, and R. M. Mazgaj, “Aluminum-Consuming Fluidized-Bed Anodes,” J. Electrochem. Soc., 137, 1851-1856 (1990)
5. J. F. Cooper, Weight and volume estimates for aluminum-air batteries designed for electric vehicle applications. Lawrence Livermore National Lab, UCRL-83881 (1980)
6. J. F. Cooper, K.A. Kraftick and B.J, McKinley, Proc. 18th Intersoc. Energy Convers. Eng. Conf., 4:1628-1634 (1983)
7. E. J. Rudd and S. Lott, The development of aluminum-air batteries for application in electric vehicles. Final Report, SAND91-7066, Sandia National Labs. (1990)
8. W. H. Hunt, Jr., “Technology Insights: Aluminum Air Fuel Cell Becoming Commercially Viable,” The Aluminum Association, 2008
9. J. Woodall, as reported in Science Daily, “New Process Generates Hydrogen From Aluminum Alloy To Run Engines, Fuel Cells“, Purdue University, May 18, 2007
10. N. Margolis and J. Eisenhauer, “Inert Anode Roadmap: A Framework for Technology Development.” Document prepared for the Aluminum Association and the U.S. Department of Energy, Office of Industrial Technology, Columbia, MD (1998)
11. K. R. Van Horn, P. R. Bridenbaugh, and J. T. Staley, in Aluminum Processing: Smelting, Encyclopædia Britannica. Retrieved October 29, 2009, from Encyclopædia Britannica Online
    ]]> http://energy.sigmaxi.org/?feed=rss2&p=1185 http://energy.sigmaxi.org/?p=1114 http://energy.sigmaxi.org/?p=1114#comments Sun, 01 Nov 2009 17:33:27 +0000 Elsa http://energy.sigmaxi.org/?p=1114
    
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    Kevin DeGroat, Antares Group Incorporated (kdegroat (at) antares.org)
    Joseph Morabito, Alcatel/Lucent (morabito (at) alcatel-lucent.com)
    Terry Peterson, Solar Power Consultant (terry.peterson (at) mindspring.com)
    Greg P. Smestad, Sigma Xi Member, Sol Ideas Technology Development & Solar Energy Materials and Solar Cells Journal (smestad (at) solideas.com)

    posted November 1, 2009

    Download this paper in pdf format

    Abstract: A Systems Analysis for the solar energy industry and solar R&D is presented to identify key positive reinforcements that can accelerate the adoption of solar technologies through a process of solar value creation. Such an analysis can also identify constraints that can decelerate solar technology adoption, as well as points of leverage where investment and R&D can have the most positive impact. The approach can also be useful for explaining solar energy to a wide range of decision makers and to the public. It emphasizes two major, related challenges in achieving widespread, rapid adoption of solar energy technologies in time to have a significant impact on global energy and environmental problems. The first concerns integration of solar-generated electricity with the electric grid and this is facilitated by a “Smart Grid” infrastructure. The second challenge involves the means to continue to drive down manufacturing and deployment costs for solar energy systems and to expand manufacturing capability in order to accelerate deployment of solar energy systems. This is closely tied to market supply chain transformation that considers each step in the technology’s manufacturing and installation. The Systems Analysis suggests that there are three high leverage points: research on Solar Energy Grid Integration Systems (SEGIS), Systems Dynamics Modeling, and a Solar Industry Supply Chain Consortium. Although such an analysis is now widely accepted in the telecommunications industry, it has yet to be applied to the solar industry until now.

    Introduction

    To more rapidly reach its full potential in terms of job creation and power production, as well as economic and environmental benefits, the fledgling Solar Energy Industry must consider solar value creation on a global scale. Although there are several definitions of economic value, we shall utilize the idea that the value of an object or condition is the perceived benefit to well-being or happiness associated with its creation, consumption or use. Table 1 shows value migration as civilization has advanced through the ages. Value migrates from outmoded economic models to designs that are better able to satisfy a society’s changing priorities and perceptions of its needs. Many believe that we are migrating towards a Sustainable Energy/Information Intensity era with characteristics that are outlined in the table. The transition will present us with significant new market opportunities as well as challenges. For example, our current infrastructure for transmitting electricity (the Grid) is designed to supply energy to a distributed set of recipients from large central power plants, which was adequate when society’s main perception of the value of electricity was focused on its use in new appliances and applications. In the Sustainable Energy/Information Intensity era, a Smart Grid will transmit and distribute electricity in many directions, allowing customers to supply renewable energy to their utility, or to other locations where it has its highest value. This will allow the system to respond to new consumer priorities that barely existed in the first years of electricity generation. Examples may include:

    • the value of reducing an individual’s carbon and pollution footprint by having greater control over their energy supplies;
    • more knowledge and control over how one spends money on energy;
    • differentiating the quality and reliability of power one wants and being able to acquire it through the energy system in return for either higher rates, with more quality and reliability, or lower rates, with less quality and reliability.

    Table 1. Value migration through the various eras (ages) of human economic development. Drivers are inputs, resources or commodities that are available to allow that phase of economic development to occur. Indicators are measures that the society values as a proxy for well-being.
    

    The term Smart Grid is often used, but not always adequately explained. A full discussion of it is beyond the scope and intent of this paper and is confounded by the fact that it is only just being envisioned. It is clear, however, that it is more than just the use of Smart Meters or the inclusion of net metering. In short, a fully functioning Smart Grid will feature sensors throughout the electricity transmission and distribution grid to collect data so that real-time, two-way communications will move that data and electricity between utilities and consumers. When fully developed, the Smart Grid will enable informed participation by customers, accommodate all generation and storage options, enable new products, services and markets and provide the power quality for a range of needs. It will optimize the efficient utilization of all energy sources while operating resiliently by handling many disturbances in the grid automatically. To accomplish this, embedded, low-cost computing power is necessary for both power sources and consumer applications to allow for efficient generation and transmission at lower overall costs.

    Some descriptive terms being used for the future Grid include: self-configuring, self-healing, and smarter. These are biological terms, suggesting that we are shifting from a machine-like linear economy to a web-like economy. The new infrastructure will change and evolve in ways similar to natural biological and ecological systems. Like natural systems, information and energy systems will possess emergent properties that we have yet to comprehend. Some factors that have been used to describe the driving forces behind the transition include: costs, capital competition/cooperation, China, consumers, climate/carrying capacity and convergence. The latter term represents an increase in, and ubiquity of, computing power. Clearly, a framework and tool is needed for understanding the transition to a Sustainable Energy/Information Intensity economy and assessing the opportunities and resources required for the complex, inter-related bottlenecks facing the solar industry.

    Luckily, such a framework exists and has proven itself in other high-technology industries. It is based on Systems Analysis or Systems Thinking, which leads us to a process for estimating or inferring how local policies, actions, or changes influence the state of other parts of a system. A system is a group of interacting, interrelated, and interdependent components that form a complex and unified whole. Systems include R&D departments in organizations, or the circulatory system in your body. Examples of Systems Analysis are numerous in Supply Chain Design, Program Management, and in Biology and Ecology. Systems Thinking shows how events that are separated in distance and time can interact, how the rules of the system drive its behavior and how small things can cause large changes in complex systems. One goal of Systems Thinking is identifying “leverage,” that is, seeing where actions and changes lead to sustainable improvement. This approach was applied successfully in the telecommunications industry by Alcatel-Lucent and is now widely accepted in that industry. A graphical way to display such Systems Analysis includes the Senge Diagram and this is shown for the solar industry in Figure 1. This diagram and the application of Systems Analysis to both solar R&D and the solar industry are the central and novel aspects of this paper.

    
    Figure 1a: Senge Diagram of a Systems-focused U.S. Solar Industry. SEIA is Solar Energy Industries Association. SEPA is Solar Electric Power Association. SEMI is Semiconductor Materials International. ASES is American Solar Energy Society. SEGIS is Solar Energy Grid Integration Systems. GAO is the Government Accountability Office. CRS is Congressional Research Service. DOE is the Department of Energy. (View larger image.)

    
    Figure 1b: Gear-based representation of Figure 1a applied to the international arena. Blanks represent unforeseen factors such as the U.S. Stimulus Package (ARRA), education and workforce development or the rise of LED-based solar lighting applications.

    There are several interrelated cycles in the Senge diagram that influence one another like gears in a gearbox. These include: innovation supported by agencies such as the Department of Energy (DOE), Federal Policy, the Global Solar Industry and its target market. Feeding into these cycles are various types of analyses, investments and industry groups such as the Solar Energy Industries Association (SEIA), Solar Electric Power Association (SEPA), and the Semiconductor Equipment and Materials International (SEMI). Delays are represented by breaks in the cycle and these are places where leverage is most important to consider for removing (or minimizing) barriers and bottlenecks. If all the cycles are considered as a whole, the gears move faster and the solar industry can enter a “virtuous cycle” of lower cost, higher value, new technology and expanded markets. Viewing the solar industry from a Systems Perspective using a Senge diagram can yield useful insights and produce valuable recommendations. This is the goal of this paper. Rather than discuss the specific prospects, potential and promise of solar energy systems and technologies (for this, see the literature cited and bibliographic entries,) this paper will focus on Systems Thinking as a method for understanding and managing the development of these technologies so that they can live up to whatever potential that they can ultimately attain.

    Challenges for Photovoltaics

    Solar-generated power is seen as both a distributed resource (e.g. on buildings) and a large-scale central source deployed for (or by) utilities. Both have roles in the overall energy mix of a region or nation. There are two major challenges to the deployment of solar energy systems at large scales and on a schedule adequate to make a major impact on global energy and environmental problems: integration with the electric grid and innovation along the whole supply chain. Many utilities and developers argue that solar energy systems must compete with central station generation on the same terms as fossil fuels when it comes to dispatch, transmission and reliability. The intermittent nature of solar energy is often cited as a major obstacle.

    Another challenge involves producing enough PV modules and bringing them together with mounts, wiring and power conditioning electronics (e.g. inverters) to make an impact on a nation’s energy generating capacity. PV modules are created by assembling many types of materials into an integrated package that must withstand long-term outdoor exposure. A PV supply chain is a system of companies, people, technologies, information and resources involved in moving a solar product and its energy output from its supplier to a customer. Supply chain activities transform natural resources, raw materials (such as glass, silicon or tellurium) and other components into a finished product that is delivered to the end customer. As the photovoltaic (PV) experience and growth curve shown in Figure 2 illustrates, PV module costs approximately equivalent to those of fossil fuels may not be very far in the future. Deviation from the historic trend during 2005-2007 is known to be due to a temporary shortage of purified silicon, coupled with installation incentives in Germany and Spain. This imbalance between supply and demand is resolved and this is borne out in preliminary data for 2009 from Navigant Consulting. Not shown in Figure 2 are the so-called Balance of Systems (BOS) costs, those that are other than the PV module costs, but are necessary to complete the installed PV system so that it can deliver energy to the consumer. PV systems have followed the trend of a 50:50 cost breakout between PV modules and BOS costs for nearly 30 years and there is no compelling evidence to suggest that this will change anytime soon. Also indicated in the figure is an estimate of the constraint on the penetration of solar-generated power from PV into the existing grid, which is not designed to manage large quantities of intermittent energy supplies.

    
    Figure 2: PV module price experience curve and a projected PV price scenario. The mnemonic for this plot is the number 20. That is, for each doubling of cumulative production, the average module price decreases by about 20% percent. For the projections at the right, similar to the long-term historic value of 20% per year is assumed. If these trends continue, silicon-based PV will reach costs comparable to the least-cost conventional options by about 2030. This will occur as PV grid penetration reaches approximately 20%.

    This generally occurs on conventional grid systems when PV penetration reaches 15% to 25%. For more on this, and for current ideas regarding storage and an energy mix that includes wind, solar, hydroelectric, geothermal and conventional sources, refer to literature cited at the end of this paper. Additional challenges for PV are listed as bottlenecks in the Senge Diagram in Figure 1a.

    PV systems have an expected life of 20 years or more, so it is difficult to predict how markets will evolve and displace earlier generations based on actual market experience. In biology, scientists study changes over generations of fruit flies as a proxy for studying human evolution and biology. Similarly, technologies and industries with rapid product cycles can be used as “industrial fruit flies” to understand how technologies and industries like PV may evolve. Figure 3 illustrates an analysis of the life cycle of over 300 different (non-solar) technologies and products that provide insights on how PV technologies may evolve. The curves are not theoretical; they are based on data from several industries. They show how cost and risk (on the y axis) decline as technologies move from future and emerging stages to wide application and, finally, legacy deployment. The value to a company that introduces the products at first rises and then peaks as a technology moves from emerging to wide application. It then declines sharply as the product moves completely into wide application and eventually legacy status. It is important to understand where different solar technologies are in their life cycle and where to focus research and development (R&D) on issues that are the most relevant to solar energy’s success, and to national interests. As solar technologies move toward competition based on value-chains in supply and manufacturing, agreements between industry participants on standards for raw materials, manufacturing equipment and processes will become essential for rapidly expanding manufacturing capacity and deployment.

    
    Figure 3: Technology Life Cycle Factors obtained from several hundred different non-solar technologies and products. PV and solar technologies would currently be in the future and emerging portions of the figure, but are expected to advance to the right.

    Solutions
    Based on Systems Analysis represented by Figure 1 and a consideration of such technology life cycle factors, Figure 4 summarizes the desired progression of solar R&D from a project to a program focus with system-focused R&D. Three broad solutions emerge regarding the challenges previously described. These solutions are: SEGIS research, systems dynamics and modeling, and the creation and nurturing of a PV supply chain consortium.

    
    Figure 4: Value for Project and Program Oriented Solar Research. Solar Technologies are currently in the sequential and traditional R&D portions of the figure, but can be pushed into the more rapidly expanding systems-focused R&D curve to the right.

    Solar Energy Grid Integration Systems (SEGIS) Research

    DOE’s Solar Energy Grid Integration Systems (SEGIS) focuses on developing intelligent hardware that interconnects PV systems to an evolving “Smarter” electrical grid. Our Systems Analysis suggests that programs such as SEGIS can ensure that the Smart Grid adequately addresses opportunities for solar technologies such as PV. Key SEGIS research includes:

    • Energy storage. This ranges from small capacity, quick discharge, devices to deal with the short-term impact of transient clouds on power output to longer capacity storage so solar generation can more completely cover periods of peak demand;
    • Communications. Embedded computing power at generation sites and communication networks between sites are needed to make PV more effective in responding to instantaneous grid and weather conditions. For instance, avoiding automatic PV cutoff when it would harm grid stability, or shifting PV to recharging (e.g. in conjunction with plug-in hybrids) when its output is less valuable to the grid;
    • Standards. Improving national and international standards for PV modules and BOS elements in a Systems Thinking framework can allow PV systems to be combined with other generation sources to alleviate problems caused by PV’s intermittent output. As will be discussed shortly, this can lead to consortiums that can foster collaboration between PV module makers and integrators.

    In this context, large-scale (so called high penetration) PV systems are being explored worldwide. For example, at a subdivision in Rancho Cordova, California, over 91 solar Smart Homes are each equipped with 2 kW of PV that feed into the grid. Other test sites include the 8 MW PV plant in Alamosa, Colorado, and the14 MW PV plant at Nellis Air Force Base in Nevada. Such SEGIS research is also critically important to improving utilities’ management of traditional energy generation and demand-side resources and for improving the utilization of their existing infrastructure. Overcoming grid integration limits for PV depends heavily on utilities and their regulators. Their concerns need to be addressed through continued and expanded reseearch into technolgies that will ease PV grid integration, accompanied by strong outreach and collaboration t o better define issues and arrive at solutions that make both technical and economic sense.

    Energy System Dynamics and Modeling

    For System-focused development, it is important to use platforms, processes, tools and methods to rapidly test ideas that can effectively integrate solar energy into our economy. Stakeholders can build and maintain system models that are used throughout the development lifecyle shown in figure 3. One such tool is the Solar Advisor Model (SAM) that allows an analysis of the impact of changes to the physical system on the overall economics (including the levelized cost of energy, LCOE). It handles residential to utility-scale systems and a variety of technology-specific cost models for several and, eventually, all solar technologies.

    The Utility industry needs models to understand local variations in solar resources and how this impacts PV output over large geographical scales (e.g. southwestern U.S.). This can allow an understanding of how widespread PV can be managed across the entire system. Detailed modeling of interactions can help improve grid operating strategies and approaches. For example if scattered clouds are shadowing a large solar field in one location, this can be rapidly communicated to adjacent solar, wind or conventional power plants and can, perhaps, be mitigated. This is only possible by combining energy systems with embedded computing power and communications networks.

    Understanding and modeling system dynamics can also help explain solar energy to a wide range of decision makers and to the public. For example, while the term sustainability is often invoked to support solar and other renewable energy technologies, it is almost always loosely defined and rarely quantified*. An analysis that considers the greenhouse gas emissions of a technology over its life cycle can make sustainability more quantifiable and comparable between technologies. Global economic output ($25.4 trillion/year) can be related to global carrying capacity for carbon emissions (for the sake of argument, 8.6 trillion kg Global Warming Potential (GWP)), which is the maximum amount of carbon that can be emitted if climate change is going to be managed effectively according to Intergovernmental Panel on Climate Change (IPCC) analysis. This type of methodology quantifies sustainability and makes it a comparative metric by relating economic value – measured in dollars, just like GNP – to the carrying capacity of the environment for emissions. This results in a measure of sustainable productivity of approximately $3/kg GWP. If a business or industry’s economic output is less than $3/kg GWP it emits, its production is not sustainable. This example is for GWP, but the approach has been applied to other emissions and environmental problems (see references).

    Systems dynamics and modeling can also quantify the life cycle analysis of solar energy technologies in terms of Energy Return on Energy Invested and Energy and CO2 payback times. Fthenakis and co-workers have published comparisons of emissions from solar and other energy technologies and have formulated a detailed plan to integrate solar energy into the U.S. electricity grid. Considering emissions provides a quantitative economic basis for environmental and economic comparisons of solar technologies with other energy technologies and industries.

    Solar Industry Consortium to Address Supply Chain Challenges

    Supply chain issues are going to be increasingly important if PV is going to maintain the growth rate it needs to have a significant impact on global energy use (see Figure 2). Without major innovation in the supply chain to keep improving costs and performance, maintaining the 20% growth curve will be very difficult. In addition, there are concerns about the availability of highly pure thin film absorber materials such as Cadmium Telluride (CdTe) and Copper Gallium Indium Diselenide (CIGS) necessary for Terawatt (TW) deployment of PV. Although these aspects have yet to be fully addressed, it should be pointed out that, until recently, demand has not warranted sufficient exploration to positively identify reserves and resources.

    With these aspects in mind, Systems Analysis suggests that the PV industry needs PV supply chain consortiums. One example may be taken from Sematech, organized by the semiconductor industry to develop and maintain a roadmap for standards and goals for equipment development. Sematech started with an emphasis on processes, but that effort soon slowed because of intellectual property issues concerning different manufacturers’ formulations and methods – just as a PV consortium would likely break down over each company’s “secret recipe” for their materials and cells. When competition is dominated by product innovation, collaboration is difficult. Where Sematech found its first success was in equipment standards and goals and competition focused on the value-chain. This will probably be the case for PV as well.

    Crystalline silicon PV technology is moving into the stage of market development where supply chain innovation is the key to continued expansion and competition (see Figure 3), while solar cells utilizing thin-films are just entering this stage of development. Manufacturing line equipment for the crystalline silicon PV technologies that currently lead the market, and the supply chains that provide their materials and components, are the most promising near-term opportunity for an industry consortium. There is common interest in standardizing processing and handling equipment in order to gain economies of scale from equipment and material suppliers. The industry also needs tools to effectively monitor and optimize manufacturing while the manufacturing process is occurring, rather than relying on end-of-the-line diagnostics that identify problems too late to avoid large production losses.

    Newer PV companies may be overestimating the value of protecting their trade secrets compared to what could be gained through collaboration; successful first steps by a consortium focused on crystalline silicon PV could persuade them to overcome their reluctance to collaborate. Such a consortium should possess objective technical expertise so that it can form a consensus on standardization and crosscutting research on supply chain issues.

    Equally important as collaboration and consortia is peer review. This is the process of subjecting an idea, work, or research plan to the scrutiny of others who are among a community of experts in the same or similar field. The process of performing a meaningful and impartial review should itself be viewed as a cycle in the Senge diagram of Figure 1, and plays an essential role in a Systems Approach aimed at achieving high quality R&D in a minimum amount of time. This is because supply chains cannot be developed internally, and peer review breaks down barriers that collaboration on standards and equipment, and supply chain consortia, cannot address.

    Conclusions

    PV markets are growing rapidly, but from a very small base. Annual growth of approximately 20% will need to continue for solar to have a major impact on generating capacity in the U.S. and the world. Obstacles to overcome include achieving grid integration at high market penetration and the shifting of the focus from product innovation to supply chain innovation. The results from the PV experience curve strongly suggest that major breakthroughs are not required. However, targeted research for sustaining innovation is needed, as well as more effective industry collaboration. These will allow solar deployment to follow its past trends for cost and performance improvements through 2050, the time frame necessary to address climate change. Systems Thinking techniques may be used to study any kind of system: natural, scientific, engineered, human, or conceptual. Solar Energy R&D and Industry Drivers should be considered in the context of Systems Analysis and such perspectives lead to a multidisciplinary, collaborative approach. Although the analysis presented in this paper has focused on non-concentrator solar photovoltaic systems, it can, in principle, also be applied to concentrator PV (CPV) and concentrating solar power plants (CSP). It can explain and optimize the engine of growth for the fledgling solar industry to identify areas where spending and support can accelerate this value creation process. This will create a new economic era for the 21st century.

    This new economic era will involve a modification of society comparable in scale to only two other changes: the Agricultural Revolution and the Industrial Revolution. Sustainable Energy and Information Intensity are two essential technologies for this transformation. Sustainability will be a major driver of technological innovations such as the Smart Grid. This, in turn, will be a product of the Internet and energy management of sustainable energy sources made possible by low cost and embedded computational power in energy-generating and energy-utilizing devices.

    * Work done in collaboration with David Dickinson. Additional technical papers and examples of the (STM) methodology are listed in teh references.

    Literature and Acknowledgements

    This paper represents the views of the authors and does not represent the views of the U.S. Department of Energy. However, the authors developed this analysis (and its content) by substantial participation in the DOE Solar Energy Technologies Program’s 2009 Annual Program Peer Review held on March 11, 2009. More information is expected to be available on the DOE website. The following bibliographic entries are organized by topic area and in chronological order.

    The Nature of Technology in R&D

    Arthur, W. Brian. The Nature of Technology: What It Is and How It Evolves, New York: Free Press/Simon and Schuster Publishing. 2009.

    Hamm, Steven. The Radical Future of R&D. Business Week. (September 7, 2009): 1.

    Solar Energy Technology and Economics

    Komp, Richard J. Practical Photovoltaics: Electricity from Solar Cells. Ann Arbor: Aatec Publications. 1995.

    Koeleian, Gregory A; and Geoffrey McD. Lewis. Application of Life-cycle Energy Analysis to Photovoltaic Module Design. Progress in Photovoltaics: Research and Application, 5 (1997): 287-300.

    Andersson, B. A.; S. Jacobsson. Monitoring and assessing technology choice: The case of solar cells. Energy Policy, 28/14 (2000) 1037-1049; Andersson, B. A. Materials availability for large-scale thin-film photovoltaics. Progress in Photovoltaics: Research and Applications, 8/1 (2000): 61-76.

    Markvart, Tomas; and Luis Castañer. Solar Cells: Materials, Manufacture and Operation. New York: Elsevier. 2005.

    Swanson, Richard M. A Vision for Crystalline Silicon Photovoltaics. Progress in Photovoltaics: Research and Applications, 14 (2006): 443-453.

    Fthenakis, Vasilis M; Hyung Chul Kim. Greenhouse-gas emissions from solar electric- and nuclear power: A life-cycle study. Energy Policy, 35/4 (2007): 2549-2557.

    Pacca, Sergio; Deepak Sivaraman; Gregory A. Keoleian. Parameters affecting the life cycle performance of PV technologies and systems. Energy Policy, 35 (2007): 3316-3326.

    Feltrin, A.; and A. Freundlich. Material considerations for terawatt level deployment of photovoltaics. Renewable Energy, 33 (2008): 180-185.

    Zweibel, Ken; and Vasilis Fthenakis. A Solar Grand Plan, Scientific American, 298/1 (2008): 64-73.
    del Cañizo, Carlos; Gonzaol del Coso; and Wim C. Sinke. Crystalline Silicon Solar Module Technology: Towards the 1 Euro Per Watt-Peak Goal. Progress in Photovoltaics: Research and Applications, 17 (2009): 199-209.

    Fthenakis, Vasily; James E. Mason, and Ken Zweibel. The technical, geographical, and economic feasibility for solar energy to supply the energy needs of the U.S. Energy Policy, 37 (2009): 387-399.

    Smart Grid accessed on September 11, 2009.

    SEGIS accessed on September 11, 2009.

    Solar Advisor Model (SAM) accessed on September 11, 2009.

    Jacobson, Mark Z.; and Mark A. Delucchi. A Path to Sustainable Energy by 2030, Scientific American, 301/5 (2009): 58-65.

    Mints, Paula. A Pause in PV Industry Demand Growth offers time for Innovation, Solar Outlook, ISO2009-4 (August 31, 2009): 1-7. Navigant Consulting .

    Wiser, Ryan; Galen Barbose; Carla Peterman; Naim Darghouth. Tracking the Sun II: The installed Cost of Photovoltaics in the U.S. from 1998 – 2008. Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory (October 2009).

    Fthenakis, V.; W. Wang; and H. C. Kim. Life cycle inventory analysis of the production of metals used in photovoltaics. Renewable and Sustainable Energy Reviews. 13 (2009): 493-517.

    Value Creation Publications

    Senge, Peter, The Fifth Discipline. New York: Doubleday/Currency Press. 1990.

    Morabito, Joseph M.; Steven T. Walsh; Matthias Merges; and Bruce A. Kirchhoff. Portfolio Management for the Commercialization of Advanced Technologies. Institute of Electrical and Electronic Engineers (IEEE) Conference. San Juan: May 5, 1999.

    Morabito, Joseph M.; Steven T. Walsh; Matthias Merges; and Bruce A. Kirchhoff. A Value Creation Model for Measuring and Managing the R&D Portfolio. Portland International Conference on Management of Engineering and Technology (PICMET). Portland: July 28, 1999.

    Linton, Jonathan D.; Steven T. Walsh; Bruce A. Kirchoff; Joseph M. Morabito; and Matthias Merges. Selection of R&D Projects in a Portfolio. IEEE (2000): 506-511.

    Morabito, Joseph M.; Matthias Merges; and Bruce A. Kirchhoff. A Value Creation Model for Measuring and Managing the R&D Portfolio. American Society for Engineering Management (ASEM) in Engineering Management Journal, (March 2001): 19-22.

    Linton, Jonathan D.; Steven T. Walsh; and Joseph M. Morabito. Analysis, Ranking and Selection of R&D Projects in a Portfolio. R&D Management, 32/2 (March 2002): 139-148.

    Jackson, Michael C. Systems Thinking: Creative Holism for Managers, Wiley Publishers November 14, 2003.
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    ]]> http://energy.sigmaxi.org/?feed=rss2&p=1114 http://energy.sigmaxi.org/?p=1095 http://energy.sigmaxi.org/?p=1095#comments Fri, 30 Oct 2009 02:31:51 +0000 Elsa http://energy.sigmaxi.org/?p=1095
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    James C. Townsend, Ph.D., World Harmony Organization; Genei, Inc.; Sigma Xi; DrJCTown@cox.net

    Francis C. W. Fung, Ph.D., World Harmony Organization; Genei, Inc.; francis@worldharmonyorg.net

    posted October 29, 2009

    Download this paper in pdf format

    Abstract: This paper describes innovations which are aimed at “overcoming the implementation lag” in solar energy commercialization within the utility industry. Existing sustainable solar energy technologies have been shown to be “good enough” for electrical utility generation; however, to promote their widespread adoption, they must be made more economical than non-sustainable fossil-fuel generators. New advances in solar thermal concentration for generation by Stirling engine technology, perhaps combined with thin-film photovoltaic (PV) technology, promise to reduce the cost of electrical power generation below that from natural gas powered generators. The solar concentrator is a large parabolic dish made up of a number of mirror panels, as in previous technology. The innovation is that the panels consist of many identical, interlocking, metallic flat-plate reflector elements. This construction provides many advantages. The recent advent of thin-film photovoltaic (PV) technology gives rise to a new “see-through” application — the combination of concentrator and PV technologies. This white paper discusses the possibilities and advantages to be gained through these innovations.

    Introduction

    Photovoltaic (PV) electrical generation has become more efficient in recent years, but it still has been unable to move beyond very limited, special purpose usage, and it is only able to capture a relatively small amount on the incident radiation. The cost of silicon solar cells makes the time for recovery of investment too long for utilities to consider their use; it has confined them to applications such as space, localities without convenient utility power, and dedicated conservationists for whom the cost is not the primary consideration. More general acceptance of PV electricity requires better economics.

    However, solar power is more than just light — to fully utilize the bountiful solar power readily available, it is necessary consider a wider spectrum of solar energy. Tests have proven that three-dimensional (3D) solar thermal concentrators can provide the high temperatures required for utility and industrial thermal applications. The demonstration in 1984 by Sandia/SES of a 25kW concentrator and Stirling engine generator system was a technical success that opened the way for further large 3D solar concentrator development.

    Disappointingly, as successful as the demonstration was, current dish designs for utility-scale applications are still based on its quarter-of-a-century-old technology. Yet there remain many issues of economics, durability, maintenance, weight, transportation, ease of construction, and life cycle cost for utility-scale solar concentrators. For example, although Sandia/SES generated power that was fully acceptable for the electric grid, the costs of maintaining the system led to its abandonment after a relatively short time. Because the mirrors were glass, they were heavy and fragile, requiring a sturdy and heavy structure to support them and hold the parabolic shape as the dish tracked the sun. The silvered mirror surface also was susceptible to degradation or damage, and its reflectivity was only moderate in much of the solar thermal spectrum. “What remains to be demonstrated,” noted NREL’s Sara Kurtz, who leads the lab’s high-efficiency solar research, “is whether solar concentrators – especially their sensitive optics – will prove reliable in the field.”

    Describing a press conference in Paris by Todd D. Stern, the State Department Special Envoy for Climate Change, the May 27, 2009 New York Times Dot Earth blog reported:

    “The United States is proposing to make a seismic change in U.S. policy,” he said. “The president is proposing to do that, and Congress as well is in the middle of working on this.”
    “We’re probably the only country that’s talking about actual hard mandatory policy all the way out not just to 2020 but 2025, ‘30, ‘40, ‘50, not simply goals,” Mr. Stern said.
    “We’ve got a huge problem we’re facing,” he said. But added that the world has to be realistic as well, avoiding overly ambitious agreements that, while flashy, can’t be carried out. “My watchword, throughout all of the time I’ve been in office, is science and pragmatism,” Mr. Stern said. “We need to have an agreement that is consistent with the science but that is also pragmatic so you can actually get it done.”

    To meet the presidential goals, utilities, the U.S., and the world needs fields of modular solar power collection systems that are light, efficient, and cost-effective to install, and that have lower maintenance concerns than current systems and greater robustness in harsh environments, such as blowing sand. Solar thermal concentrators combined with thin-film photovoltaics could well be the commanding technology for such solar power applications.

    Solution

    The solution to the problem stated above is a new generation of 3D solar concentrators that lends itself to utility-scale applications. The proposed Solar Thermal Concentrator (STC) dish is innovative, going beyond the 1984 technology of the Sandia/SES project and overcoming its limitations. A large electric utility system made up of mass-produced 50kW STC modules with an advanced Stirling engine and generator should be able to generate utility-grade electric power at the $0.85 per kWh cost quoted for natural gas fired systems, but with less maintenance and no ongoing fuel costs. The addition of transparent thin-film PV sheets to increase the power generated holds promise of providing an even further cost advantages. The performance improvements that modular electric generation by solar thermal concentrators with Stirling engines and transparent thin-film PV sheets provide will make this new technology a viable and preferred option for electric utilities. A search of over 30,000 patents has shown that the technology described below represents innovations in dish design and reflective coatings.

    The Solar Thermal Concentrator

    The principal problem with current solar concentrator dishes is their use of glass mirrors. The new technology to replace curved glass mirrors is a faceted panel of flat-plate reflective mirror elements (see Figure 1). The proprietary connectors joining these identical metallic elements together are adjustable so that the reflection from each element falls within the target area of a Stirling engine*. Typically, that target area is eighteen inches across and the individual elements are ten inches square, an optimal size for maintaining full concentration of the sunlight on the target while allowing for some inaccuracy or deflection of the elements. These faceted panels have the advantage that they are more robust, lighter, easier to construct and transport, and lower in cost compared to fragile, heavy, expensive conventional curved glass mirror panels.

    

    Note that the STC itself has a large cost advantage over conventional glass-mirror concentrators because the STC’s optimally sized, interlocking mirror elements are light weight and load bearing and so do not require the cost of a heavy metal support structure. Mounting the lighter weight dish on a lighter supporting frame improves this cost advantage further. Moreover, this weight reduction translates into substantial savings in transportation costs to the remote locations that are most suitable for solar power collection fields.

    A second new technology is the reflective surface of the mirror elements. There are three different coatings proposed for the elements (see photos in Figure 2).

    

    • The “good mirror element” is tough, durable, non-oxidizing, and resists the worst desert erosion. It thus does not need glass protection or layers of abrasion- and UV-protective coatings. Although its thermal reflectivity is somewhat less than glass mirrors, it would be very cost effective for large utility applications, especially factoring in its long lasting and low maintenance characteristics.
    • The “better mirror element” has a proprietary one-coat, extra hard, abrasion protective coating over a high-reflectance surface on a metallic substrate. The protective layer has sufficiently high transparency that this element’s thermal efficiency surpasses that of glass mirrors.
    • The “best mirror element” has a coating that reflects more of far-infrared thermal energy than the other two; the one-coat hard coating protects it also. Unlike first-surface silver, it is resistant to UV and oxidation and thus does not require glass or multilayer coating protections. Independent laboratory measurements show that it is 15 percent higher in efficiency over a wide range of solar energy compared to the “better mirror element,” so it is especially well suited to applications where space is limited. In addition, there is a process for recovering and recycling this coating material that makes the life cycle cost lower than conventional glass mirrors, for which silver recovery is uneconomical.

    Among these three reflective elements and the solar concentrator dishes built from them are the improvements in economics, durability, maintenance, weight, transportation, ease of construction, and life cycle cost that can satisfy the needs for utility power generation.

    Thin-Film Photovoltaic Technology

    A new development in photovoltaic technology promises to make its use on a large scale feasible. Companies such as SunGroupUSA are now producing thin-film photovoltaic (PV) sheets that, although of lower efficiency than monocrystalline silicon cells, are much lower in cost. In addition, SunGroupUSA’s PV sheets are transparent enough to suggest new applications. Among these are the use of thin-film photovoltaic panels on windows in buildings with large expanses of glass area, such as greenhouses and high-rise office buildings, to take advantage of thin-film electric generation as well as sunlight utilization (see Figure 3). The thin-film PV sheets from SunGroupUSA are now a well proven technology, having been used for the Beijing Olympics (accepted as meeting both the Olympic Project energy savings and environmental criteria) and in such large building projects as the window curtain walls of the Princess Tower (tallest apartment building in the world) and Gate Tower in Dubai.

    

    Next Step

    The next step is the combination of thin-film photovoltaic technology with thermal solar concentrator technology to obtain the maximum energy from the sun. The discrete-element construction philosophy for the faceted parabolic STC dish assembled from flat reflective elements lends itself well to be fitted with transparent thin-film PV flat sheets for solar power applications. A serious investigation of the combined solar thermal concentrator thin-film PV concept will be required to demonstrate the relative feasibility of the various configurations of the PV sheet on or above the reflective elements and to design and produce a large-scale working prototype of a selected configuration. Only then can utilities be engaged for a demonstration of the full commercialization concept.

    To this end, Genei and SunGroupUSA are collaborating with the World Harmony Organization to propose that the U.S. Department of Energy (DoE) fund an examination of the innovative and transformational technology represented by STC combined with thin-film photovoltaics. The first phase will be to perform full thermal and electric generation measurements of five 50”x40” parabolic mirror panels consisting of individual 10”x10” mirror elements with attached thin-film PV sheets as shown in Figure 1. The five 50”x40” parabolic mirror panels will serve to test different mounting or attachment configurations of the thin-film PV sheet on or above the 10”x10” flat mirror elements and to determine which SunGroupUSA thin-film PV sheets, having various degrees of transmittance and electric power output, provide the highest combined efficiency.

    The second phase will involve the design, manufacture, and test a large-scale prototype. The purpose of this phase is to validate that the benefits shown by the concept demonstration can be scaled to a full-size 50 kW electric generation module. The third phase will engage manufacturing partners to commercialize the combined solar thermal concentrator and thin-film PV power generation concept in a utility application. This phase should lead to broad acceptance of the concept by the electric utility industry.

    Note that the 10”x10” load bearing, interlocking, flat mirror elements with transparent PV sheets and the 3D faceted mirror panels assembled from them can be custom sized for various new or retrofitted solar thermal dish applications. Figure 4 shows how a combined thin-film PV and light-weight metallic mirror panel design could replace glass mirrors in concentrators such as this Sandia/SES electric power generation dish. Shown are the heavy, expensive standard 4′x3′ curved glass mirror panels of 1984; each replacement panel would be a 50″x40″ faceted mirror, consisting of twenty identical, inexpensive, light-weight, interlocking, optimized, load-bearing, 10″x10″ flat mirror elements.

    

    Cost Advantage of the Concept

    The cost advantage of combined solar concentrator and thin-film PV modules will depend on a number of factors. While sources and costs of most materials are known, labor costs and factors affected by the STC design details are yet to be determined. In addition, there are factors affected by the thin-film PV sheets, including their transmittance, diffusivity, and reflectivity, their mounting or attachment configuration, and the resulting additive power generation capability that the STC/PV design can attain. These factors are the subject of the project’s first phase. However, the cost advantage is expected to be substantial enough to make this system a preferred option for the electric utility industry.

    Conclusion

    The addition of the transparent SunGroupUSA thin-film PV sheets over the reflecting surface of the faceted solar thermal concentrator (STC) dish should substantially increase the power generated per unit area of the dish. Consequently, each STC module could generate more power, or the STC dish size could be decreased. The greater power per unit area will decrease the environmental impact of solar power generation by decreasing the overall size of the field of collectors needed to generate a given number of kilowatts of electricity.

    Because the thin-film PV sheets are relatively inexpensive (compared to the cost of conventional PV silicon chips) and the mounting will be simple, the percentage increase in cost of the combined STC/PV dish will be substantially less than the increase in power it is expected to generate. Thus, a large electric utility system made up of mass-produced 50kW STC/PV modules should generate electricity for substantially less than $0.85 per kWh, quoted for natural gas fired systems. But, the STC itself already has a large cost advantage over conventional glass-mirror concentrators because the STC’s optimally sized, interlocking mirror elements are low cost, light weight, and load bearing; not only does the lighter weight dish not include a heavy and costly metal support structure, a lighter, less expensive frame can support it. All of this weight reduction, even with the PV sheets added, translates into substantial savings in transportation costs to the remote locations most suitable for solar power collection fields.

    The first phase of this project would test several simple configurations for mounting the various thin-film PV sheets on the reflecting elements to determine their highest combined efficiency. Later phases would mature the concept to the point of acceptance as a preferred option by the electric utility industry.
    We believe that power generation by the proposed solar thermal concentrator and Stirling engine combined with transparent PV thin films is the most scientifically testable and pragmatic technology for advancing the “seismic change in U.S. policy” the president has proposed. Moreover, it will create a large job market for solar power manufacturers and help dispel the current financial crisis.

    * The connectors, reflective coatings, and certain other details are proprietary information or the subjects of patents applied for and the property of Genei, Inc.

    Additional Information

    There is additional information on the Genei Website.

    Bibliography

    Proprietary Technology and Intellectual Property (PPA’s filed jointly by Genei Principal Scientists, Dr. Francis C. W. Fung and John E. Orava):

    1. “Business Method to Increase Gold Utilization in the Solar Industry”, 11/12/2008
    2. “Means & Methods for Increasing EMF Concentrator Efficiency”, 11/28/2008
    3. “Retrofit Spray Regenerator for Solar Stirling Engine Dish”, 11/12/2008
    4. “Efficient Reflective Array Concentrator”, 10/6/2008
    5. ““Multi-Use Electromagnetic Energy Concentrator and Converter”, 9/26/2008

    Other papers (available on request):

    1. “Green Energy for Electricity Initiative (GENEI) Alternative to Nuclear and Fossil Energy.” Francis C. W. Fung, Ph.D., World Harmony Organization, July 18, 2008 (see http://worldharmonyforum.blogspot.com/ and also http://www.scribd.com/doc/4012048/Green-Energy-for-Electricity-Initiative-Genei-Revised)
    2. “The Promising Future of Stirling Engines in China.” Francis C. W. Fung Ph.D., Visiting Consultant, Institute of Engineering Thermophysics, Chinese Academy of Sciences, 2nd International Conference on Stirling engines, Shanghai, China, June 21-24, 1984.
    ]]> http://energy.sigmaxi.org/?feed=rss2&p=1095 http://energy.sigmaxi.org/?p=1092 http://energy.sigmaxi.org/?p=1092#comments Tue, 27 Oct 2009 14:35:23 +0000 Elsa http://energy.sigmaxi.org/?p=1092 I’ve been compiling Sigma Xi’s Science in the News newsletters lately, and was struck by the fact that, in the last few days, there have been two articles about Native American objections to emerging sources of energy–in totally different parts of the country, and about totally different sources of energy.

    On Sunday, the Washington Post covered the Indigenous Uranium Forum, which took place in New Mexico over the weekend. Attendees opposed renewed uranium mining for nuclear energy, recalling the health problems such mining caused to their communities in the past. Plus there are objections to mining on sacred land.

    Over on the East Coast, two tribes are opposing Cape Wind, an offshore windfarm proposed for Nantucket Sound. They say the sound should be listed as a traditional cultural property on the National Register of Historic Places, and that desecrating the site with wind turbines would be detrimental to their spiritual well-being. The Boston Globe had that story.

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