Oilprice.com & World Resources Institute
Despite their promise over the past decade or so, biofuels have been found to be a very inefficient way to generate energy, are bad for the environment and even contribute to world hunger, according to a new report by the World Resources Institute (WRI).
In fact none of these conclusions is new. Research into biofuels for years has focused on making them more potent. And no one has ever thought cutting down trees, for example, is good for the environment, even if more trees can be grown. And as for nutrition, who benefits more from corn: a hungry child or an automobile?
Certainly, natural waste products can contribute to bioenergy, but dedicating broad acreage to raising crops not for food but for energy creates unfair competition with a more important enterprise of growing crops and providing grazing land for livestock, according to the WRI, a global research organization based in Washington. The paper is the ninth installment in a series of reports by WRI, titled Creating a Sustainable Food Future.
Dedicating crops and/or land to generating bioenergy makes it harder to sustainably feed the planet.
- The world needs to close a 70 percent “food gap” between crop calories available in 2006 and those needed in 2050. If crop-based biofuels were phased out by 2050, the food gap would shrink to 60 percent. But more ambitious biofuel targets—currently being pursued by large economies—could increase the gap to about 90 percent.
- Wider bioenergy targets—such as a goal for bioenergy to meet 20 percent of the world’s total energy demand by 2050—would require humanity to at least double the world’s annual harvest of plant material in all its forms. Those increases would have to come on top of the already large increases needed to meet growing food and timber needs. Therefore, the quest for bioenergy at a meaningful scale is both unrealistic and unsustainable.
Bioenergy is an inefficient use of land to generate energy.
- Fast-growing sugarcane on highly fertile land in the tropics converts only around 0.5 percent of solar radiation into sugar, and only around 0.2 percent ultimately into ethanol. For maize ethanol grown in Iowa, the figures are around 0.3 percent into biomass and 0.15 percent into ethanol. Such low conversion efficiencies explain why it takes a large amount of productive land to yield a small amount of bioenergy, and why bioenergy can so greatly increase global competition for land.
- Solar photovoltaic (PV) systems’ conversion efficiency—and therefore their land-use efficiency—is much higher. On three-quarters of the world’s land, PV systems today can generate more than 100 times the useable energy per hectare than bioenergy is likely to produce in the future even using optimistic assumptions.
Large estimates of GHG emissions reductions from bioenergy are based on a misplaced belief that biomass is inherently a carbon-free source of energy. Other types of renewable energy hold more promise to curb emissions and not compete with food security goals.
- Most calculations claiming that bioenergy reduces greenhouse gas emissions do not include the carbon dioxide released when biomass (e.g., from maize) is burned. They exclude it based on the theory that this release of carbon dioxide is matched and implicitly “offset” by the carbon dioxide absorbed by the plants growing the biomass feedstock. Yet if those plants were going to grow anyway (e.g., for food), simply diverting them to bioenergy does not remove any more carbon from the atmosphere and therefore does not offset emissions from burning that biomass. In effect, these analyses “double count” plant growth and thus “double count” carbon, leading to overly optimistic estimates of emissions reductions.
- There are some sources of “additional” biomass that are consistent with a sustainable food future and will therefore reduce greenhouse gas emissions (relative to the use of fossil fuels) because they do not compete with food production or otherwise make dedicated use of land. Examples include growing winter cover crops for energy, timber processing wastes, urban waste wood, landfill methane, wood from agroforestry systems that boost productivity, and crop residues that are not otherwise used. However, their potential to meet a sizeable share of human energy needs is modest.
Download the WRI Report (pdf): Avoiding Bioenergy Competition for Food Crops and Land