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Why Dedicating Land to Bioenergy Won't Curb Climate Change

This post is part of WRI's blog series, Creating a Sustainable Food Future. The series explores strategies to sustainably feed more than 9 billion people by 2050. All pieces are based on research being conducted for the 2013-2015 World Resources Report.

How does bioenergy contribute to a sustainable food and climate future?

A new WRI paper finds bioenergy can play a modest role using wastes and other niche fuelstocks, but recommends against dedicating land to produce bioenergy. The lesson: do not grow food or grass crops for ethanol or diesel or cut down trees for electricity.

Even modest quantities of bioenergy would greatly increase the global competition for land. People already use roughly three-quarters of the world’s vegetated land for crops, livestock grazing and wood harvests. The remaining land protects clean water, supports biodiversity and stores carbon in trees, shrubs and soils—a benefit increasingly important for tackling climate change. The competition for land is growing, even without more bioenergy, to meet likely demands for at least 70 percent more food, forage and wood.

Competition for Land

Opportunities do exist to grow more food on the same land and to reinvigorate some degraded, highly underutilized land. But meeting food and timber needs without clearing more forests will already require full use of this potential. Providing just 10 percent of global transportation fuel from biofuels in 2050 would require roughly 30 percent of the total energy in all the crops people harvest today.

Turning to so-called cellulosic energy crops such as fast-growing grasses would not avoid this land use competition. On cropland, even with optimistic estimates, such energy crops will struggle to produce even the same amount of ethanol per acre (hectare) as corn ethanol does today. Growing these crops on pasture or forest land would sacrifice food and carbon storage benefits.

Some institutions have called for producing 20 percent of human energy needs from bioenergy of all sorts by 2050. That would require an amount of biomass equal to all the plants harvested annually across the entire world today: all the crops, crop residues, wood and grasses eaten by livestock. The world does not have the room.

Beneath these global figures is an even simpler truth: every time we dedicate land to bioenergy, we sacrifice the opportunity to use that land for some other human need, ranging from food to carbon storage. The trade-off is a bad one because bioenergy is an inefficient use of land. Even ethanol from sugarcane in Brazil only converts around 0.2 percent of the energy in the sun’s rays to usable energy, and cellulosic ethanol would optimistically only be a little better.

Bioenergy Isn’t Carbon-Free

This opportunity cost of land also explains why bioenergy will rarely reduce greenhouse gas emissions. Studies that find bioenergy reduces greenhouse gases incorrectly view plants as a carbon-free fuel and ignore the very real carbon emitted by burning them. The theory has been that the original growth of the plants absorbs enough carbon to offset the carbon released when they burn. But if those plants were going to grow and absorb carbon anyway – and typically they would – then diverting them to bioenergy does not remove any additional carbon from the atmosphere. Instead, bioenergy comes at the expense of some other uses of those plants. When the expense is food or agricultural land, the effect is poorer nutrition. When the expense is forests or woody savannas, the effect is less stored carbon.

Some alternative sources of bioenergy still exist without dedicating land for bioenergy. Municipal waste and some forest and crop residues provide potential. But because of limited quantities of such potential biomass, ambitions need to remain modest. Replacing traditional but inefficient use of fuel wood or charcoal with improved bioenergy would also be a net gain.

Solar Cells Offer an Alternative

The good news is that standard solar cells available today can generate more than 100 times as much usable energy per acre (hectare) as bioenergy even using optimistic projections for bioenergy’s future. When used with electric engines in cars with more efficient batteries, solar benefits can rise to 200 or 300 times the efficiency biofuels. And unlike bioenergy, solar energy works great in deserts and on rooftops without competing for fertile land.

Solar energy will need a variety of improved storage techniques to realize its full attention to meet human energy needs, and there are unlikely ever to be electric airplanes. But the world can boost solar production enormously even with today’s technology, and promising storage technologies are emerging for the future.

The ultimate challenge is that land, particularly fertile land, is a finite resource that becomes ever more valuable as the world becomes more crowded. Using solar technologies to produce more of our energy and cropland to produce our food is the wiser, more efficient and food-secure path to a sustainable food and climate future.

Learn more about the Creating a Sustainable Food Future series.


This report makes no mention of algae oil production, which can be done using salt water or waste water in areas where farming is not possible. The oil yields of algae are up to 30x greater than food crops.

The problem is the biofuel mandates and wrong GHG accounting for biomass.

Thank you Tim. Yes dedicating land to bioenergy make no sense. Not in terms of GHG reduction, feeding the world, getting value for the public climate money or protecting biodiversity. However, looking at the actual policies that are the driving force for burning the food and forests of the world, they are not actually about laying claim on land areas. The problematic policies eg in EU are "only" mandating the use of biofuels, without counting the emissions from land use change. Or impose GHG reduction targets on electricity sector while wrongly counting biomass as zero GHG.
Ill considered biofuel mandates and wrong GHG accounting practice for biomass is the culprit. Therefore it feels a little like barking in the wrong direction only to mention the problem in dedicating land to bioenergy.

Sustainably harvested 'waste' biomass and energy crops in selected situations can provide energy in the form of electricity, which provides base load power, which solar cannot provide and liquid transportation fuel, which electricity cannot provide anywhere near scale today. Searchinger proposes a false choice between biofuels and 'good clean energy'. We should be supporting all types of renewable energy. WRI does a disservice to all of the intelligent good hearted folks that are trying to solve the energy dilemma we have by pitting one alternative energy source against another. Searchinger's research on indirect land use has been discredited and should not be recycled again. It's as if WRI was working for the American Petroleum Institute subjecting alternative energy solutions to higher standards than any other nascent industry. Bad science and bad policy.

The kind of ethanol added to gasoline is anhydrous, which is basically moonshine with the last few percentage points of water removed because gasoline (oil) and water don't mix. You say ethanol has a third less energy content than gasoline, which translates into a 33% mileage loss over gasoline. When added to gasoline at a ratio of 10% (E10), it's claimed to cause 3% mileage loss. But that doesn't explain how 100% ethanol, even hydrous ethanol (moonshine with the water left in it), does not cause a 33% mileage loss in a high compression engine.

What's really behind the loss of mileage with E10 has already been mentioned, oil and water don't mix, meaning the hydrocarbon chain connecting gasoline to ethanol is very weak, so weak that too much water causes a “phase separation”. This is where the ethanol and water sink to the bottom of the tank with the gasoline floating on top of it, which causes a great deal of damage to engines. What no one talks about is what happens even with the bare minimum exposure to water, even normal water vapor in the atmosphere that fuel is exposed to in the piston chamber. This causes that weakly connected hydrocarbon chain to break so there are too distinct fuels being fired. So when the spark plug ignites what is supposed to be 87 octane fuel, the ethanol is now at 113 octane and the gasoline 83 octane. This is because in order to achieve an 87 octane balance when adding 113 octane ethanol at 10%, the gasoline it's added to is 83 octane.

Low compression engines, like those that use regular gasoline, cannot compensate for a fuel mix of 113 and 86 octane at the same time, it's impossible. This results in the claimed 3% mileage loss along with high emissions of acetaldehyde and formaldehyde. I t also causes hotter running engine because so much of the fuel is not combusting, it's rather burning. The truth however is it causes a greater loss than 3%. Depending on the type fuel, engine, and ignition system, most suffer a 10% mileage loss or greater, meaning adding ethanol to gasoline at 10% by volume is a total wash even if it didn't require any energy to produce. This is while hydrous ethanol causes no mileage loss, meaning the whole Midwest could be gasoline free using their own self sustaining 100% ethanol fuel rather than lobbying the federal government to force the rest of us to truck or train it to our regions so it can be used to ruin our fuels.

To sum it up, even if ethanol came out of the ground ready to be added to gasoline, even if it fell like rain or magically appeared in our fuel tanks already mixed with our gasoline, it would still do more harm than good.

This assumes that all biofuel feedstock would be produced on crop lands which is not the case. Lots of opportunities exist with under utilized lands such as road rights of way. In Illinois alone, this represents 100,000 acres of the most productive land in the world. Combine this with the biomass in municipal solid waste (half of MSW is biomass), forestry byproducts, landscape waste, food waste, etc and it adds up fast. That's why the DOE estimates that the US will process a billion tons of biomass (equivalent to the size of the US coal industry) by 2030 into enough fuel to replace 30 percent of petroleum.

Well, it is all based upon an assumption that "cellulosic ethanol " conversion is not very efficient. However, if 90% of the Cellulose could be converted, efficiently, then things would be quite different.

Termites know how; maybe humans can figure this out?

Please re-do your calculations based on this new efficency!

Do you really think that it will be possible to move trucks by electricity? We need other alternatives. Solar energy will not save the planet and the problem behind food are the terrible management, distribution and logistic. More than 40% of the world grain production is lost before it reaches our plates. We need to improve the land efficiency and reduce the food waste. The best solution will be a mix of many energy sources.

The interview completed just now by Mr. Searchinger with Philadelphia NPR affiliate WHYY program "Radio Times" was superb. Acknowledging that his interviewer, radio talkshow host of many decades, Ms. Marty Moss-Coane, is herself a proven expert in her field and was undoubtedly already pretty well informed & well prepared, his ability to smoothly include the range of info, from narrow data & stats to global nearly philosophical issues of the setting of priorities was greatly appreciated.

In today's interview on WHYY 91FM "Radio Times" his conclusion included the observed fact that it is materials sciences combined with electronics design which together represent the essence of economic, scientific and quality-of-living gains over the past several decades (NB this is my personal recollection, and should be attributed to me & not to him). So it is clear that energy needs are far more likely to be met through these sciences rather than through trying to squeeze a trifle more energy from a kilogram of spinach.

Tim, you need to spend more time on a farm. You're not understanding how most crops are used. The corn or soybeans can be used for both food and fuel. In corn, its a waste to feed the starch to cattle. They really don't glean any energy from it. Thats why you feed them hay with their corn ration. If they could utilize the starch they wouldn't need the hay. But, if you first convert that starch to ethanol, it concentrates up the protein left behind. So now you have what the cattle really need, protein, and its much more efficient to deliver it that way. Same goes for soybeans, they press the oil out, which is actually too rich to feed to livestock anyway, and they get a soybean meal byproduct. So both food and fuel is created. As for cellulosic ethanol, you assume there has to be separate, dedicated acres for this to work. But that is not the case. Extra biomass is generated when these grain crops are produced. Whether its corn, wheat, sorghum, or any other grain they produce biomass which is left in the field. So now that same acre has the potential to produce grain for food and fuel, as well as biomass for additional fuel or power generation. And before you get concerned that this would mine the carbon from the soil remember, there is just as much biomass below ground in the roots as it produced above ground. So the real way to save the carbon is not from leaving biomass on top of the soil, its by reducing tillage operations.

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