Let them eat biofuels!

bastille.jpgFood riots? Rationing? Governments overthrown?

… a series of poor harvests in the area led to soaring bread prices, provoking food riots…. A worker’s daily bread took 97% of his income…. With bread prices at record levels, hungry mobs attacked the gates … where customs collected taxes on incoming grain convoys. They raided every possible source of arms, ending up with capturing the Bastille prison.

Oh, sorry, that was 1789. No worries, then. Not like that lead to a violent revolution or anything.

Anyway, the Washington Post has a terrific front-page article, “The New Economics of Hunger: A brutal convergence of events has hit an unprepared global market, and grain prices are sky high. The world’s poor suffer most,” which is the first in a series.

No, national and global mandates for biofuels (= bad energy policy) aren’t the only reason for this emerging catastrophe. Obviously, high oil prices (= bad energy policy) play a role. And then there are those poor harvests in places like Australia due to climate change (= bad energy policy). OK — the last one was kind of a stretch, given that the amount of climate change to date was probably all but inevitable. But my point is that if we don’t drastically reverse our self-destructive energy policies soon, things are going to get much worse….

We have mandates for far more biofuels (see “The Fuel on the Hill — The Corn Supremacy), and we are going to see much higher energy prices (see “Peak Oil? Bring it on!“) and much worse global drought and desertification (see The Century of Drought“).

What they heck are people supposed to eat then — Biofuels? Apparently that’s what politicians in this country and Europe think. Heck, in a Friday article, “IEA warns against retreat on biofuels,” the International Energy Agency, based in Paris, ironically enough, has this to stay:

Biofuel production is critical to meeting current and future fuel demand in spite of its possible role in driving up food prices, the west’s energy watchdog has warned.

Some may believe that biofuels are not a major contributor to the recent food price spike, but the conservative European magazine, The Economist, certainly does (see “The End of Cheap Food,”), calling the price rise “the self-inflicted result of America’s reckless ethanol subsidies” and pointing out last December the amazing statistics:

In other words, the demands of America’s ethanol programme alone account for over half the world’s unmet need for cereals. Without that programme, food prices would not be rising anything like as quickly as they have been. According to the World Bank, the grain needed to fill up an SUV would feed a person for a year.

The head of the International Monetary Fund shares this view, writing in the Financial Times last week (here):

Higher food prices over the past few years in part reflect well-intentioned, yet misguided policies in advanced economies, which attempt to stimulate biofuels made from foodstuffs through subsidies and protectionist measures.

And Prime Minister Gordon Brown says the British government “is concerned that biofuels are stimulating inflation and pushing up food prices around the world.”

The consensus among leading biofuels experts presenting at an American Meteorological Society seminar Friday I attended (see here, I’ll post the video when available) was that governments should ban all biofuels made from crops or on productive lands — in part because such biofuels almost certainly don’t provide a net reduction in greenhouse gas emissions and in fact probably increase emissions.

One thing seems very clear to me — if we don’t get on the path to 450 ppm atmospheric concentrations of carbon dioxide immediately, then we are facing a future of 9 billion people and soaring energy prices and drastic reductions in arable land and water. In such, a future any competition between food and fuel will easily be won by food, as it should be.

25 Responses to Let them eat biofuels!

  1. David B. Benson says:

    Yes, ethanol from corn is an idea that only a politician (paid by a lobbiest) would love. Biodiesel from rapeseed is almost, but not quite, so bad. Biodiesel from soybeans? Bad, but I don’t know how bad.


    (1) No more biodiesel from palm oil, because all the palm oil is going as food.

    (2) Ethanol from sugarcane is a win-win for everybody because sugar is a glut on the world market. While one can eat a little of it, you’ll die of malnutrition if you attempt to just eat sugar. (Could probably use sugarbeets as well for ethanol, I just haven’t read of anybody doing this.)

    (3) Poor croplands will grow undesirable, but nutritionally adequate, foods such as sweet potato and casava. Both make fine bio-fuel feedstocks. Rural people in Africa, how need both food and fuel, use the best cropland for food and the less good cropland to grow those foods, yes, foods, as bio-fuel feedstock. They are paid to deliver the biofuel feedstock and also can afford to buy the resulting product (much less expensive than importing petroleum products, whose price has sky-rocketed.)

    (4) The plantings and the southern hemisphere returns for the 2008 crop year make it appear to become the largest on record. This will build up the world’s food reserves and help eliminate the current speculation which is also helping to drive up prices.

    There is ample crop land to feed everybody in the world, and in a much healthier way than currently. [Did you know that obesity is a worse malnutirion problem, world-wide, than insufficient calories is?) There is enough extra, lower grade land to grow enough bio-energy feedstock for the entire world’s current energy needs, four times over, without touching the world’s forests even. [Probably better to use only about a quarter of that.]

    Here is a link to the papers in which the bio-energy estimates are developed:

  2. Earl Killian says:

    David, Ethanol from sugarcane is not a win-win. Searchinger’s paper supplement said, “if grazers displaced for sugarcane burn down rainforest to replace grazing land, the payback period could rise to 46 years, depending on the type of forest. If sugarcane is produced in wetlands other countries, which has been common in the United States, the emissions could be significantly greater.”

  3. David B. Benson says:

    Earl Killian — That is a common misconception:

    (1) Sugarcane does not grow well on (ex) tropical rain forest soils. In Brazil, the sugarcane growing areeas are all south of the Amazon basin.

    (2) The tropical rain forest distruction cycle goes like this (in Brazil):

    (i) Legal, semi-legal and illegal cutting of trees. Very lucrative.

    (ii) Squatters then raise a few years of crops on the cleared areas until the soils are depleted.

    (Iii) Ranchers then move onto that land for a few more years until the soils are destroyed.

    (iv) Go back to (i) and repeat.

  4. Earl Killian says:

    David, I understand the process. However, that is not what Searchinger was talking about. Sugarcane is grown in the Cerrado, which is not rainforest, but tropical savanna. As sugarcane takes over it displaces cattle from the land. That pushes the cattle to other areas (other parts of the Cerrado, or newly cleared lands).

  5. Hal Levin says:

    Stop feeding so much grain and using so much land for cattle and sheep and use the food to feed people directly. Clearing rain forest for grazing or pasture land or to raise grain for cattle, sheep, pork, and other animal food is a major contributor to GHG emissions. Why is there so much resistance to acknowledging the very high costs of beef, pork, and lamb products?

    Look at the numbers:
    Beef, pork, and lamb contain about 3 grams of embodied Carbon per gram of product and cost about US$1500 to $2000 per gram CO2 emitted (Jones, Kammen, and Horvath, in press).

  6. Lamont says:

    Hemp produces more energy per acre than corn or sugar and grows on more marginal lands so it wouldn’t necessarily need to displace food. And as a side effect of industrial production, the hemp plant also displaces plots of cannabis grown for more psychoactive qualities.

    Better conversion of cellulose to ethanol would only make hemp more attractive as a biofuel.

  7. Kiashu says:

    I’m very much against biofuels. As a greenish type, it’s a great disappointment to me, because in principle they’re great – grow, process, burn, all carbon neutral, lovely. But in practice biofuels make climate change worse.

    And even if we put the entire world on a minimum ration of grain, putting all the rest, and all fruit, vegetables, sugar and oilseed into biofuels, and if we had a Magic Energy Fairy that could do all the conversion without using a single joule of energy, we’d still only get a single barrel of biofuel each – compared to the 4.7bbl used per person annually around the world (0-2 in impoverished countries, 2-7 in developing countries, 7-15 in efficient developed nations, 15+ in inefficient ones).

    Biofuels will only ever supply a small part of our fuel needs, and will make a very large part of climate change and resource depletion along the way.

    Like hydrogen cars, they’re just another excuse for delaying real action, an attempt to pretend to solve the problem while continuing our current wasteful business as usual. It’s adjusting the seat belt while we’re driving off the cliff.

  8. Peter Wood says:

    I have heard that one thing affecting food prices is increased affluence is leading to more demand for meat, and this is driving up the price of grains, because more grain is used to feed livestock. Livestock is also a significant greenhouse polluter (predominantly from “enteric emissions”, burping and farting), with cattle being worse than sheep, which are worse than than other animals. Livestock farming is also a major driver of deforestation and land clearing, and hence more emissions. The habitat destruction associated with land clearing is a major driver of species loss, and could exacerbate any species loss associated with climate change.

    Suppose that the livestock sector was covered by a carbon price. This would most probably lead to reductions in production and less greenhouse intensive production. As well as being a relatively cheap way of reducing emissions, and decreased production (especially for beef), would lead to less demand for grain, and reductions in grain prices. It may also be a relatively cheap way of reducing emissions. It will also be a necessary part of reducing methane concentrations, which we need to do in order to reduce the greenhouse gas concentration down to the CO2 concentration (which we also need to bring down).

    Reducing direct and indirect emissions from livestock could also take up a significant portion of a ‘wedge’. Some countries have very high emissions from livestock and/or land clearing. In Australia for example, there are more emissions from livestock than there are from passenger cars.

  9. I love eating meat but one of the most potent tools we have in combating global warming is reducing our consumption of it. In a list of 24 technologies that I have compiled that would combat global warming now, veganism figures pretty high on the list. Short of veganism, we may have some more options if the latest news is to be trusted so here are the options that I know of that would mitigate livestock methane:

    1) 5-day or 7-day/week Veganism
    2) Test-tube “meat”
    3) Bio-engineered non-methanogenic (word?) bacteria for livestock rumens
    4) Shifting to chicken and aquaculture from mammalian livestock

    There are a few wedges in there, given that supposedly as much as 20% of GHGs are attributable to livestock. Numbers 1,2, and 4 would go a long way to alleviating food shortages and the non-GHG environmental costs of keeping mammalian livestock.

    Chefs and culinary schools could go a long way to helping us reduce the GHG impact of food by creating more satisfying low-GHG impact foods. I mean really satisfying…not just satisfaction that comes from wishful thinking and high mindedness. I had some really good vegan food at Cafe Gratitude in Berkeley which was different but was quite filling and tasty. Imagine if 3 star Michelin chefs got into the game.

  10. Hal Levin says:

    Rethinking the meat guzzler NY times January 27, 2008 by Mark Bittman

    A SEA change in the consumption of a resource that Americans take for
    granted may be in store — something cheap, plentiful, widely enjoyed and
    a part of daily life. And it isn’t oil. It’s meat.

    The two commodities share a great deal: Like oil, meat is subsidized by
    the federal government. Like oil, meat is subject to accelerating demand
    as nations become wealthier, and this, in turn, sends prices higher.
    Finally — like oil — meat is something people are encouraged to consume
    less of, as the toll exacted by industrial production increases, and
    becomes increasingly visible.

    Global demand for meat has multiplied in recent years, encouraged by
    growing affluence and nourished by the proliferation of huge, confined
    animal feeding operations. These assembly-line meat factories consume
    enormous amounts of energy, pollute water supplies, generate significant
    greenhouse gases and require ever-increasing amounts of corn, soy and
    other grains, a dependency that has led to the destruction of vast swaths
    of the world’s tropical rain forests.

    Just this week, the president of Brazil announced emergency measures to
    halt the burning and cutting of the country’s rain forests for crop and
    grazing land. In the last five months alone, the government says, 1,250
    square miles were lost.

    The world’s total meat supply was 71 million tons in 1961. In 2007, it
    was estimated to be 284 million tons. Per capita consumption has more
    than doubled over that period. (In the developing world, it rose twice as
    fast, doubling in the last 20 years.) World meat consumption is expected
    to double again by 2050, which one expert, Henning Steinfeld of the United Nations , says is resulting in a “relentless growth in livestock production.” Americans eat about the same amount of meat as we have for some time, about eight ounces a day, roughly twice the global average. At about 5 percent of the world’s population, we “process” (that is, grow
    and kill) nearly 10 billion animals a year, more than 15 percent of the
    world’s total.

    Growing meat (it’s hard to use the word “raising” when applied
    to animals in factory farms) uses so many resources that it’s a challenge
    to enumerate them all. But consider: an estimated 30 percent of the
    earth’s ice-free land is directly or indirectly involved in livestock
    production, according to the United Nation’s Food and Agriculture
    Organization, which also estimates that livestock production generates
    nearly a fifth of the world’s greenhouse gases — more than

    To put the energy-using demand of meat production into easy-to-understand terms, Gidon Eshel, a geophysicist at the Bard Center, and Pamela A. Martin, an assistant professor of geophysics at the University of Chicago , calculated that if Americans were to reduce
    meat consumption by just 20 percent it would be as if we all switched
    from a standard sedan — a Camry, say — to the ultra-efficient Prius.
    Similarly, a study last year by the National Institute of Livestock and
    Grassland Science in Japan estimated that 2.2 pounds of beef is
    responsible for the equivalent amount of carbon dioxide emitted by the
    average European car every 155 miles, and burns enough energy to light a
    100-watt bulb for nearly 20 days.

    Grain, meat and even energy are roped together in a way that could have
    dire results. More meat means a corresponding increase in demand for
    feed, especially corn and soy, which some experts say will contribute to
    higher prices.

    This will be inconvenient for citizens of wealthier nations, but it could
    have tragic consequences for those of poorer ones, especially if higher
    prices for feed divert production away from food crops. The demand for
    ethanol is already pushing up prices, and explains, in part, the 40
    percent rise last year in the food price index calculated by the United
    Nations’ Food and Agricultural Organization.

    Though some 800 million people on the planet now suffer from hunger or
    malnutrition , the majority of corn and soy grown in the world feeds
    cattle, pigs and chickens. This despite the inherent inefficiencies:
    about two to five times more grain is required to produce the same amount
    of calories through livestock as through direct grain consumption,
    according to Rosamond Naylor, an associate professor of economics at
    Stanford University . It is as much as 10 times more in the case of grain-fed beef in the United States.

    The environmental impact of growing so much grain for animal feed is
    profound. Agriculture in the United States — much of which now serves the
    demand for meat — contributes to nearly three-quarters of all
    water-quality problems in the nation’s rivers and streams, according to
    the Environmental Protection Agency .
    Because the stomachs of cattle are meant to digest grass, not grain,
    cattle raised industrially thrive only in the sense that they gain weight
    quickly. This diet made it possible to remove cattle from their natural environment and encourage the efficiency of mass confinement and slaughter. But it causes enough health problems that administration of
    antibiotics is routine, so much so that it can result in
    antibiotic-resistant bacteria that threaten the usefulness of medicines
    that treat people.

    Those grain-fed animals, in turn, are contributing to health problems
    among the world’s wealthier citizens — heart disease, some types of cancer, diabetes . The argument that meat provides useful protein makes sense, if the quantities are small. But the “you gotta eat meat” claim
    collapses at American levels. Even if the amount of meat we eat weren’t
    harmful, it’s way more than enough.
    Americans are downing close to 200 pounds of meat, poultry and fish per
    capita per year (dairy and eggs are separate, and hardly insignificant),
    an increase of 50 pounds per person from 50 years ago. We each consume
    something like 110 grams of protein a day, about twice the federal
    government’s recommended allowance; of that, about 75 grams come from animal protein. (The recommended level is itself considered by many
    dietary experts to be higher than it needs to be.) It’s likely that most
    of us would do just fine on around 30 grams of protein a day, virtually
    all of it from plant sources .

    What can be done? There’s no simple answer. Better waste management, for one. Eliminating subsidies would also help; the United Nations estimates
    that they account for 31 percent of global farm income. Improved farming
    practices would help, too. Mark W. Rosegrant, director of environment and
    production technology at the nonprofit International Food Policy Research
    Institute, says, “There should be investment in livestock breeding
    and management, to reduce the footprint needed to produce any given level of meat.”

    Then there’s technology. Israel and Korea are among the countries
    experimenting with using animal waste to generate electricity. Some of
    the biggest hog operations in the United States are working, with some
    success, to turn manure into fuel.

    Longer term, it no longer seems lunacy to believe in the possibility of
    “meat without feet” — meat produced in vitro, by growing animal
    cells in a super-rich nutrient environment before being further
    manipulated into burgers and steaks.

    Another suggestion is a return to grazing beef, a very real alternative
    as long as you accept the psychologically difficult and politically
    unpopular notion of eating less of it. That’s because grazing could never
    produce as many cattle as feedlots do. Still, said Michael Pollan , author of the recent book “In Defense of Food,” “In places where you can’t grow grain, fattening cows on grass is always going to make more sense.”
    But pigs and chickens, which convert grain to meat far more efficiently
    than beef, are increasingly the meats of choice for producers, accounting
    for 70 percent of total meat production, with industrialized systems
    producing half that pork and three-quarters of the chicken.

    Once, these animals were raised locally (even many New Yorkers remember the pigs of Secaucus), reducing transportation costs and allowing their manure to be spread on nearby fields. Now hog production facilities that resemble prisons more than farms are hundreds of miles from major population centers, and their manure “lagoons” pollute streams
    and groundwater. (In Iowa alone, hog factories and farms produce more
    than 50 million tons of excrement annually.)

    These problems originated here, but are no longer limited to the United
    States. While the domestic demand for meat has leveled off, the
    industrial production of livestock is growing more than twice as fast as
    land-based methods, according to the United Nations.

    Perhaps the best hope for change lies in consumers’ becoming aware of the true costs of industrial meat production. “When you look at
    environmental problems in the U.S.,” says Professor Eshel,
    “nearly all of them have their source in food production and in
    particular meat production. And factory farming is ‘optimal’ only as long
    as degrading waterways is free. If dumping this stuff becomes costly —
    even if it simply carries a non-zero price tag — the entire structure of
    food production will change dramatically.”

    Animal welfare may not yet be a major concern, but as the horrors of
    raising meat in confinement become known, more animal lovers may start to react. And would the world not be a better place were some of the grain
    we use to grow meat directed instead to feed our fellow human

    Real prices of beef, pork and poultry have held steady, perhaps even
    decreased, for 40 years or more (in part because of grain subsidies),
    though we’re beginning to see them increase now. But many experts,
    including Tyler Cowen, a professor of economics at George Mason
    University, say they don’t believe meat prices will rise high enough to
    affect demand in the United States.

    “I just don’t think we can count on market prices to reduce our meat
    consumption,” he said. “There may be a temporary spike in food
    prices, but it will almost certainly be reversed and then some. But if
    all the burden is put on eaters, that’s not a tragic state of

    If price spikes don’t change eating habits, perhaps the combination of
    deforestation, pollution, climate change , starvation, heart disease and animal cruelty will gradually encourage the simple daily act of eating more plants and fewer animals.

    Mr. Rosegrant of the food policy research institute says he foresees
    “a stronger public relations campaign in the reduction of meat
    consumption — one like that around cigarettes — emphasizing personal health, compassion for animals, and doing good for the poor and the planet.”

    It wouldn’t surprise Professor Eshel if all of this had a real impact.
    “The good of people’s bodies and the good of the planet are more or
    less perfectly aligned,” he said.

    The United Nations’ Food and Agriculture Organization, in its detailed
    2006 study of the impact of meat consumption on the planet,
    “Livestock’s Long Shadow,” [] made a similar point: “There are reasons for optimism that the conflicting demands for animal products and environmental services can be reconciled. Both demands are exerted by the same group of people … the relatively affluent, middle- to high-income class, which is no longer confined to industrialized countries. … This group of consumers is probably ready to use its growing voice to exert pressure for change and may be willing to absorb the inevitable price increases.”

    In fact, Americans are already buying more environmentally friendly
    products, choosing more sustainably produced meat, eggs and dairy. The
    number of farmers’ markets has more than doubled in the last 10 years or
    so, and it has escaped no one’s notice that the organic food market is growing fast. These all represent products that are more expensive but of higher quality.

    If those trends continue, meat may become a treat rather than a routine.
    It won’t be uncommon, but just as surely as the S.U.V. will yield to the
    hybrid, the half-pound-a-day meat era will end.
    Maybe that’s not such a big deal. “Who said people had to eat meat
    three times a day?” asked Mr. Pollan.

    Mark Bittman, who writes the Minimalist column in the Dining In and
    Dining Out sections, is the author of “How to Cook Everything
    Vegetarian,” which was published last year. He is not a

    I am a vegetarian since 1972.
    – hal levin

  11. Thom says:

    Don’t know about the sugar cane stuff. Much of the sugar cane is Brazil is grown under slave like conditions. So the price is kept artificially low. Slavery is a hidden cost, if you will.

  12. Biofuelsimon says:

    Hey David,
    The heavily processed nature of much food consumed in the US is insulating your population from the true effects of spiraling grain prices.
    I sat through a presentation last year where someone estimated that there was about 6 cents of corn in a box of US cornflakes, I guess that component of the price has risen to 12 cents. What does a box of cornflakes command on the supermarket shelves today $1.00 to $1.50? What was it a year ago $0.90-$1.40?
    If you’re buying corn to mill and bake into tortillas at home then you see the price of your food doubling. Its a cent to a dollar that you won’t be seeing your wages doubling in the same time.

    Using corn to make ethanol is a good idea if you are only worried about getting the farming vote. It is certainly an effective way of supporting the price of corn. Which is fine if that’s what you want your policy to do. But there are side effects. There’s the water issue, the fertiliser production issue (the US is not self sufficicent in NPK and amonia fertilisers) and the fact that every bushell of corn that is used to make ethanol ties the price of corn more closely to the price of oil.

    The question that I’d like an economist to answer (and I don’t know any so I can’t ask them directly) is: when will the marginal price of grains be set by the cost of oil rather than the value to the food company. Will it be when 30%,40%,50% or more of the US corn crop goes to make ethanol? And as a follow up how does the price of oil affect that point.

    PS sugar beet can be used to make ethanol

  13. Joerg Haas says:

    Thanks Joe, this is a great piece. Marvellous, like you boiled it all down to “bad energy policy”. You are spot on!

  14. David B. Benson says:

    Earl Killian — Right. “Cain killed Abel.” Allegory for the farmer displaces the grazer.

    Thom — The 700,000+ sugercane cutters in Brazil are not paid much, but IMO are better off there than in the sums of the big cities.

    Kiashu — Your linked reference manages to be wrong more than right. Furthermore, by the studies linked in the site I previously posted, there is enough bio-energy potential to entirely meet all the world’s energy needs in 2050, projected to be about 800 exajoules.

    To the extent you think there are problems with bio-energy, try posing questions here:

  15. Paul K says:

    Some might call closed loop algae fuel a breakthrough or maybe it’s expected technological progression. Either way, it’s something I learned about at the Gas2.0 website

  16. Joe says:

    Paul — with the VC $$$ going into algae, I’d consider it an in-the-pipeline technology. That said, if I had one MMBD for every such “breakthrough” I’ve seen announced in the past two decades, I could fuel the world.

  17. Earl Killian says:

    One problem I see with algae: companies like Green Fuel are targeting fossil power plant flue gas as a CO2 source (which might be 209,000 ppm CO2 instead of 385 ppm CO2). That means the fossil CO2 is only delayed in its release into the atmosphere. True, it substitutes for crude oil CO2, but if we shut down our coal plants, where does this leave algae biodiesel if it is optimized for high CO2?

  18. Earl Killian says:

    David Benson, the Earth receives 1,100,000 EJ of sunlight on its land masses each year. The conversion of sunlight into biofuels is generally very inefficient. For example, da Rosa estimates sunlight to sugarcane ethanol as 0.13%. If most biofuel production were that inefficient, then you’re down to just 1,430 EJ of biofuels, if you use all of Earth’s land for fuel feedstock. 800 EJ would require 56% of the Earth’s land area. That seems terribly wasteful.

    One of the attractions of algae is that it might reach a couple of percent efficiency at storing solar energy (out of an approximate maximum of about 7.8%). This is still rather small compared to 30% for Stirling dishes.

    That is the production side, but the story is bad on the use side too. Feeding hydrocarbons and alcohols into an internal combustion engine wastes something like 80% of the energy in the ethanol; only 20% ends up turning the wheels. In contrast, 70% of the energy from a Stirling dish would end up as wheel motion with only 30% wasted.

  19. David B. Benson says:

    Earl Killian — I’m not recommending using just bio-energy to meet the projected need. I just point out it is possible.

    I suspect your numbers are off by quite a bit, however, The papers linked in here

    claim 1545 exajoules after leaving enough for food, fiber and forestry needs for a world population of 9 billion. The goup in The Netherlands has studied the matter for several years, so probably have thought through all the details.

    By all means use the most efficient systems possible. Dish/Stirling might well prove highly suitable in locations with enough sunlight.

  20. Paul K says:

    False either/or keeps popping up. Which is better bio-fuel or solar is irrelevant. Both are necessary. It was interesting last week how commenters touted their own particular wedge or solution while disparaging others. Yes/and has to replace no/but. It is also good to remember the longest journey begins with a single step and don’t put the cart before the horse. Replacing fossil fuel is an extremely incremental process.

    Venture capital is the engine of deployment.

  21. Earl Killian says:

    David Benson, if you don’t like da Rosa’s numbers, consider Schmer et al. in the 20080115 PNAS. They report 60 GJ / hectare / year from switchgrass. That is 0.19 W / m^2. If one assumes an average insolation of 225 W / m^2, then the efficiency is 0.08%.

    If you don’t like that, remember that Miscanthus is supposed to be 2-3x better than switchgrass, so consider the estimate on Wikipedia for Miscanthus: 7300 L ethanol / hectare / year. Since ethanol has a LHV of 21.2 MJ/L, this gives 155 GJ / hectare / year, or 0.5 W / m^2. Using the same 225 W / m^2 calculate the efficiency to be 0.2%.

    Next question: have you actually read the IEA report at the link you cite, or just the graph? Strangely, 1545 EJ never occurs in the report. The text mentions 100-300 EJ from energy crop farming on Ag land, and possibly another 40-170 EJ from organic wastes and residues, and sums by saying “could amount to 400 EJ per year during this century.” This is also before conversion to a convenient fuel, such as ethanol or biodiesel. This is the raw energy in the plants in the field. Elsewhere it lists the “Technical Potential” of biomass as 200-400 EJ. 1545 EJ is overstating this by a factor of 3.9 to 7.7.

    Moreover, there is still the usage efficiency, as I mentioned before.

  22. Earl Killian says:

    Paul K, I am not promoting, for example, 100% solar and 0% biofuel. Indeed, I would expect that biofuels may be 10% of transportation in a world that has solved its GHG emissions problem. I am simply trying to make sure that readers here understand that some of the claims made here for biofuel don’t seem to as rosy as some would suggest. I think it is important to get reasonably accurate estimates, and so I do challenge numbers I consider to fail the squint test.

  23. David B. Benson says:

    Earl Killian —- Smeets et al. obtain much higher estimates than the (older) IEA report.

    Nor am I a fan of ethanol. I opine that much better efficiences can be obtained via biomass conversion to biodiesel.

    Nor I am promoting 100% bio-energy. That would be silly.

  24. David B. Benson says:

    Forget to finish the prior post.

    However, out of the 800 exajoules of total energy usage by a population of 9 billion in 2050CE, 200–400 exajoules from bio-energy appears quite reasonable, at least at my current state of understanding.

  25. Peter Foley says:

    For years I heard how a oil tax would solve the world’s energy problems, well you got your 4$ a gallon gas in the US and you are still whining. What was the error of your thinking when you though energy was too “cheap” if isn’t fixing everything now?
    Untill meat animals start eating fossil fuels they’re not a major source of new CO2. Meat animals have displaced ‘wild’ fauna in the oxygen-carbon cycle.
    Politically vegatarism is a death sentence for any “green” political goals.