ETHANOL AND THE NET ENERGY DEBATE. By Marc Stolman, E2 Member April 30, 2005

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1 ETHANOL AND THE NET ENERGY DEBATE By Marc Stolman, E2 Member April 30, 2005 Ethanol is controversial because some scientists argue it takes more energy to make the fuel than it produces. Other scientists claim ethanol provides more energy than is required to make it. This is the net energy debate. The net energy debate is misleading because it distracts us from more important issues. The most important questions are whether the United States can find ways to reduce its dependence on imported petroleum, clean its air and improve its economy. Ethanol may help with those problems even if more power is needed to produce it from some crops, such as corn. Moreover, it is clear that ethanol made from sugarcane using current processes produces a positive energy gain. Ethanol made from grass clippings, corn stalks and other plants using future techniques may be even more beneficial. Not All Ethanol is Made the Same The arguments about net energy involve ethanol produced from corn because that is the most common crop used in the United States. However, the fuel can be made from other plants such as sugarcane, sugar beets and sorghum. A review of available literature indicates that making ethanol from sugarcane, rather than corn, takes less power, yielding substantial net energy. Fuel can be made from sugar beets, sorghum and other crops, but their energy balance has never been fully studied. And, it may be possible to make ethanol inexpensively from grass, corn stalks and other plants, producing even more power. 1

2 The Corn Ethanol Debate The arguments about the net energy balance of corn ethanol involve several scientists, all with outstanding academic credentials and impressive backgrounds. The proponents of corn ethanol are the authors of a series of reports from the United States Department of Agriculture which found that ethanol produced more energy than was consumed in its manufacturing. Housein Shapouri of the USDA, James Duffield of the USDA, Michael Wang of the DOE and Michael Graboski of the Colorado School of Mines have estimated that the energy needed for ethanol production is less than the energy produced. The opponents consist of professors from Cornell (David Pimentel) and UC Berkeley (Tad Patzek), and a research coordinator at the Optimum Population Trust (Andrew Ferguson). They argue that the USDA reports are inaccurate, the net energy balance is negative, there is excessive pollution created, and the amount of land required for growing corn makes the process unsustainable. The Two Sides Realy Aren t That Far Apart The two sides agree upon the method for calculating the net energy of corn ethanol. Both sides agree that the wel to wheel calculations should include energy consumedin making fertilizer, planting and reaping crops, transporting the corn, grinding it and distilling the so-called wine. They simply estimate the energy used at each stage and add the various inputs. When they calculate those numbers, they aren t even that far apart. Each side uses different assumptions for each of the energy inputs, but when the lists were compiled, Dr. Pimentel s 2003 numbers were only 22% greater than the 2002 report of Shapouri, Dufield & 2

3 Wang. 1 However, Pimentel and Patzek considered additional energy consumed in ethanol production that wasn t considered in the USDA reports. When their additional input factors are included, their estimates of energy required to make ethanol are more than double the amounts calculated by Shapouri, Duffield and Wang. The major differences appeared in three areas. First, the USDA report did not include energy used in manufacturing farm equipment and ethanol factories, but Pimentel and Patzek both included energy consumed in making such equipment, a difference of about 20 or 30%. Second, the USDA report gave more credit to marketable co-products made in the same process with ethanol. In their 2002 report, Shapouri, Duffield & Wang gave a credit of 19% of total energy consumed because ethanol manufacturing produced other products. Pimentel gave only a 9% credit to the co-products, and Patzek none at all. Third, the USDA did not include energy consumed irrigating cornfields, but Pimentel and Patzek both did, for another difference. When these inputs were all totaled, Pimentel and Patzek both concluded that the production of corn ethanol resulted in an energy los. Pimentel s 2003 paper concluded about 29% more energy is required to produce a gallon of ethanol than the energy that actually is in the galon of ethanol produced. Id., at pg. 2. Patzek s 2004 report, Thermodynamics of the Corn- Ethanol Biofuel Cycle, concluded ethanol production from corn is a fosil energy losing proposition. Id., at pg Table 2 in Pimentels 2003 paper, Ethanol Fuels: Energy Balance, Economics and Environmental Impacts are Negative, estimated energy inputs at 99,119 BTU per galon of ethanol. Shapouri, Dufield & Wangs 2002 report, The Energy Balance of Corn Ethanol: An Update, at Table 6, estimated those inputs at 77,228 BTU per galon. 3

4 These Are Just Estimates Both sides of the net energy debate estimated the amounts of energy required for corn ethanol production based on annual averages and hypothetical situations, rather than exact numbers. The USDA team concluded corn ethanol yields 34% more energy than is required for its production. 2 However, their estimate was based upon surveys of farms and manufacturers, and surveys are notoriously inaccurate. Professors Pimentel and Patzek concluded corn ethanol yields less energy than is used in making it. Pimentel found it 29% negative and Patzek even more than that. But their estimates considered energy used in manufacturing equipment and irrigating crops and they gave different credit to co-products, which are difficult matters to accurately forecast. Thus, a thorough review of the arguments shows that there is no right or wrong side in the net energy debate. Both sides simply tabulated estimates of the energy used in making corn ethanol, and when one puts the numbers side-by-side, it appears the authors have much in common. The Arguments Are Continuing Each side of the debate writes papers arguing for and against ethanol approximately once per year. In 2005, each has already done so. This year, the USDA published its paper, The 2001 Net Energy Balance of Corn-Ethanol. Profesors Patzek and Pimentel also produced their work, Thermodynamics of Energy Production from Biomas. TheUSDA s 2005 article concluded that corn ethanol produces 67% more energy than is required for its production. Supra, page 5. 2 See The Energy Balance of Corn Ethanol: An Update, by the USDA, 2002, at page 12. 4

5 The 2005 paper of Pimentel & Patzek didn t addres corn ethanol. However, it did discuss fuel produced from sugarcane. It found that sugarcane ethanol produces positive power. Id., at pages Patzek & Pimentel did not find the energy balance very highly positive because they deducted energy that might be used in fertilizing cane fields and restoring all the nutrients drawn from them, even though current practice is to grow cane without that. They acknowledged sugarcane has been grown without it for centuries. Id., pages 60 & 65. Thus, it is apparent from their work that sugarcane ethanol yields positive energy, using current techniques. Neither side fully discussed ethanol that might be produced from plant waste. It is possible that future scientific developments will make it possible to use grass clippings and tree branches tomanufacture fuel from such celulosic biomas at a cost competitive with petroleum. 3 And, neither side discussed the most important issues of whether the United States can reduce its reliance on imported oil, clean its environment and improve its economy. What s More ImportantAbout Corn Ethanol The most important benefit of corn ethanol is that it can reduce our dependence on imported oil. Whether it takes 29% more or 34% less energy to make the fuel, both sides agree that only a small portion of that input energy comes from petroleum. The USDA estimated 83% of required energy is derived from coal and natural gas, so at the very least, corn ethanol uses coal and natural gas to manufacture liquid fuel that can be used in place of imported oil. However, corn ethanol has serious drawbacks. The most important problems with corn ethanol are that its manufacturing probably creates more pollution than simply using petroleum, 3 Overview and Evaluation of Fuel Ethanol From Celulosic Biomas, by Lee R. Lynd,

6 so it is not a clean fuel, and its production requires almost as much fossil fuel as petroleum, so it is not a renewable fuel. It also requires vast amounts of land and water, so it does not appear possible to displace a majority of current petroleum usage in the United States with corn ethanol. Manufacturing corn ethanol probably creates more pollution than using comparable amounts of petroleum because air pollution results from burning gasoline & diesel when growing corn, more from burning natural gas and coal to distil the wine, and more in making fertilizers. Some authors have estimated the amounts of air pollution as being slightly less than would be created by burning a comparable amount of petroleum, 4 but when water pollution created by irrigating cornfields and distilling ethanol is considered, 5 the balance appears to be tilted against corn ethanol. If soil erosion is considered, it appears that growing corn and making ethanol probably degrades the environment more than simply burning petroleum. Almost as much fossil fuel is consumed in manufacturing corn ethanol as is offset by the fuel produced. The USDA survey estimated that 73% as much fossil fuel was used in producing ethanol as would have been consumed if gasoline were used. As noted above, most of the fossil fuel used is coal and natural gas. Corn ethanol is unlikely to displace a large percentage of current gasoline usage because there is not enough water or agricultural land in the United States to grow sufficient corn to offset more than a fraction of current gasoline demand. Pimentel estimated the entire amount of 4 Professor Patzek estimates that ethanol production from corn results in more air polution than petroleum. In 2004, production of ethanol from corn wil generate 8 milion tonnes of incremental CO2, over and above the amount of CO2 generated by burning gasoline. 5 About 12 gallons of wastewater are produced for each gallon of ethanol, according to Pimentel s 2003 paper. 6

7 cropland now planted in the United States would be required to displace one third of the gasoline currently used. None of the writers discussed the limited amount of water available, but it would appear that our water resources would not support a large enough increase to offset a majority of our current fuel usage. Still, corn ethanol canplay an important role in reducing America s reliance on imported oil. Properly used, it can help us move toward fuel independence. If corn were used with sugarcane, sugar beets, sorghum and other crops, it is possible that the combination could produce fuel and other products in an efficient manner with a positive net energy balance. The Available Literature Indicates Sugarcane is a Superior Feedstock. Since Brazil is the largest sugarcane ethanol producer in the world, most of the literature analyzing its energy balance and environmental impact is from that country. The most recent and comprehensive analysis, published in April 2004 by the government of the state of São Paulo 6, found that average Brazilian cane ethanol production resulted in a positive energy balance of 8.3 times the energy inputs required, while the state-of-the-art Brazilian production yielded a net return of 10.2 times input energy. Even professors Pimentel and Patzek agree that sugarcane ethanol produces positive net energy. Intheir latest paper, Thermodynamics of Energy Production from Biomas, published in March, 2005, they conclude that sugarcane is the only industrial energy plant that may be caled sustainable. Id., at pg. 72. However, they conclude the positive energy is far less than claimed by the Brazilians. First, they deduct energy that would be consumed in fertilizing cane 6 Asesment of greenhouse gas emisions in the production and use of fuel ethanol in Brazil, published by the government of the state of São Paulo, April

8 fields, even though they acknowledge sugarcane can be grown without much fertilization for over 100 years and has been grown without it for centuries all over the world. Id., at pg. 60. And, after calculating that sugarcane ethanol produces energy, they reduce the benefit by 65% since automobiles are only 35% efficient. Id., at page 69. It is difficult to compare the numbers presented by the Brazilian authors with the work of Drs. Patzek and Pimentel, because the Brazilians calculated energy consumption using kilocalories and tons of cane while Pimentel and Patzek used gigajoules and hectares. Moreover, the Brazilian paper has not been subject to the close analysis given American corn. However, it appears that sugarcane requires less energy than corn in the production of ethanol and is better for the environment. While American corn ethanol proponents claim a positive energy balance of 34% using state-of-the-art facilities, Brazilians appear to produce ethanol with a benefit many times as great. Moreover, the Brazilian writers and professors Pimentel and Patzek found sugarcane ethanol produced positive net energy, even deducting energy consumed in manufacturing equipment and deducting energy used in cleaning wastewater emitted from the process. Thus, available literature indicates sugarcane is a superior crop for ethanol production. Sugar Beets & Sweet Sorghum The fact that sugarcane is better for making ethanol requires an examination of the viability of other possible crops. Sugar beets use only half as much water as cane and can yield more sugar per acre of land. A farmer planting beets might also be able to rotate a second annual crop on the same land, making beets a possible success as an energy crop. Although sugar prices and beet growing 8

9 costs may currently prohibit the use of sugar beets for ethanol, it might be time to study the possibility that a large scale operation could succeed. Sorghum is another plant that that might yield positive net energy. Not only can the crop be grown inexpensively, but it can be rotated with other plants on an annual basis. It is also possible its processing could produce electricity, in addition to ethanol. Back to the Future It is possible to make ethanol from grass, corn stalks and other plants. However, it is more difficult to break down their fibers so they can be fermented. Anyone who has ever eaten a candy bar knows that sugar is broken down more quickly than fibrous plants, and thus we can all appreciate that the added dificulty in breaking apart celulosic molecules might make it a more expensive process. However, it may be possible in the future, and maybe even in the near future, to produce ethanol from such materials at a cost lower than gasoline. The Department of Energy estimated that by 2020, the total cost for cellulosic ethanol production would be approximately $1.29 per gallon. 7 On April 14, 2005, the National Renewable Energy Laboratory announced the completion of a study establishing a thirty- fold decrease in the cost of enzymes that can speed the conversion of cellulose to fuel. If we can convert cellulosic materials into ethanol at a low cost, the net energy required to make the fuel will likely be highly positive, and our country will be able to produce a large amount of our fuel needs from parts of plants that would otherwise be wasted. 7 Costs were given in 1998 dolars. Outlook for Biomas Ethanol Production and Demand, by Joseph DiPardo, published by the EIA. 9

10 Can Ethanol Help End Reliance on Petroleum? Ethanol might help us end our reliance on imported petroleum. Although Professors Patzek and Pimentel point out that it wil not be a silver bulet that wil end our use of oiland we must be careful not to create problems with water pollution and soil erosion, it appears we can derive fuel from plants with a positive energy balance and in a relatively clean manner. We should look at the most important issues of ending our dependence on foreign fuel, cleaning our air and improving our economy. Ethanol may be able to help with all of those problems. Although we probably will not be able to produce enough ethanol from sugarcane and corn to completely supply our transportation needs, we can probably make a significant portion of our fuel. If we can make it from grass, corn stalks and other cellulosic materials at a cost competitive with or lower than gasoline, we may even be able to produce a very substantial amount of ethanol. And, if we are able to grow our own fuel, we would probably enliven the agricultural sector of our economy, raise employment nationwide, and improve our finances. Since sugarcane appears to be a superior ethanol crop, we should expand our use of it. We must also study the possibility of growing and using sugar beets, sorghum and other plants that might contribute to energy independence. And, since scientific breakthroughs may make it possible to produce ethanol from grass and other plants at a cost competitive with gasoline, we should support research regarding it. 10

11 An Economically Viable Approach Most writers agree it would be best for our country to find clean, renewable sources of fuel and reduce our importation of oil. Most also agree the best approach would be one that uses the most cost-effective mechanisms to spur free market innovations ending in an improved economy. Currently, our country is subsidizing oil production with percentage depletion allowances, expensing of exploration & development costs, exceptions from passive loss limitations and credits for recovery costs. In 2004, those subsidies were estimated at $890 million to $1.54 billion. The cumulative amount of those subsidies has been assessed at $134 billion to $149 billion. 8 We provide additional subsidies to users of inefficient automobiles, by giving deductions of up to $25,000 to buyers of sport utility vehicles weighing over 6,000 pounds. Our government allowed deductions up to $102,000 per 6,000 pound SUV until October 22, 2004, and up to $105,000 per vehicle is still allowed in certain situations. 9 Change is Coming, Whether We Like it or Not The world appears headed toward a change in the way fuel is produced. Historic changes can sometimes be foreseen. We have an increasingly crowded planet, and two trends in history indicate that a modification in fuel production will probably occur during the lifetimes of most people reading this paper. 8 Ending the Energy Stalemate, by the National Commision on Energy Policy, at page 6. 9 See IRC Section

12 On one hand, oil production may fail to meet demand during our lifetimes. We have a finite supply of oil and it appears that when the supply is only half depleted, production will begin to fall. 10 Both developing countries and western nations are using more and more petroleum, and we may be nearing the point where production begins to decline. If demand exceeds supply, it is likely the price of gasoline will increase markedly, forcing us to change. On the other hand, we have an increasingly polluted world, where emissions harm our health and may even be causing our planet s climate to get warmer. If we cause global warming, the expected effects are likely to include a sea-level rise, altered patterns of atmospheric and oceanic circulation and increased frequency of floods and droughts. 11 We will need to reduce the amount of oil we burn to avoid harmful pollution. It is likely that one or the other of these historic trends will force us to develop new strategies for producing fuel. One way or the other, it is probable we will need to reduce our use of oil, either because the price will be too high, the effects of pollution too damaging, or both. On a national level, the need for change is even more apparent. The United States imports more than half of the petroleum it consumes and is dependent upon foreign countries for the fuel it needs. Anticipating change and moving toward energy independence would undoubtedly be good for our national security. Moreover, developing clean energy sources and meeting the world s anticipated needs can be profitable. 10 See Hubbert s Peak: The Impending World Oil Shortage, by Kenneth S. Defeyes,

13 Shall We Lead Or Shall We Follow? The only choice our country has is whether to lead theworld s change or to follow it. Leading would appear to be better for our economy. America led the industrial revolution, the development of the assembly line, the invention of computers and the creation of the internet. History has proven those innovations beneficial not only for the world at large, but also for the United States. We can ignore the evidence that a change in the way we get fuel is on its way, or we can accept that change is inevitably coming. If we can produce clean fuel, we can lead again in another industry the world needs. If we can make it without importing it from foreign countries, we can reduce our dependence on those nations. If we can grow the crops to produce it, we can spark our economy and renew our economy s agricultural sector. The choice is ours, and the only blunder worse than choosing a wrong path would be to choose none at all. 11 Ending the Energy Stalemate, Supra, at page

Everything you need to know about biomass - Interesting energy articles - Renewables-info.com

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