ENERGY CROPS¦ to rely on renewables and there is no one renewable technology at the moment that can meet our energy needs.” Globally, biomass currently provides about 46 exajoules of energy in the form of combustible biomass and wastes, liquid biofuels, renewable municipal solid waste, solid biomass, and gaseous fuels, the study says. Increasing current biomass potential will require changes to agricultural and forestry production, and the active growth of dedicated energy crops. “We’re starting to plant energy crops now, but if you look at where we are globally, the proportion of energy that’s generated from dedicated energy crops in most countries that have a large biomass supply, that tends to be quite small,” Smith points out. It’s likely that bioenergy cropping systems of the future will have primary, secondary and even tertiary uses, propelling bioenergy systems into mainstream markets, according to the study. In addition, dedicated energy crops have not undergone the centuries of im-
provement that characterized major food crops, so there’s still plenty of room to grow. “Many of the energy crops we’re starting to use, like miscanthus and switchgrass, we’ve only really started to use them,” Smith says. “We haven’t had many years of selective breeding or even genetic modification with these crops. So I think there’s a great potential to increase yield in the future as we find better genotypes and better ways of managing the crops.” In the U.S., the study’s authors cite, long-term breeding of switchgrass is beginning to produce large yield gains that will continue to improve. And hopefully other energy crop improvements won’t be far behind. But the U.S. isn’t in the region that tops the list of technical energy crop potential in 2050. Instead, South America takes a powerful lead with an estimated 189 exajoules per year, followed distantly by central Africa with 86, according to the study. The regional breakdown of the potential of about 400 exajoules is based on an imaging assessment model that esti-
mates the technical potential of industrialized countries, which includes the U.S. and Europe, at 30 exajoules. Latin America’s estimated potential for 2050, divided into two regions, is 200 exajoules; Africa’s is 145 and divided into five regions; and China, divided into four regions, has a technical potential of 21 exajoules. South America also comes out on top in estimated area available for biomass production in 2050, at 0.63 gigahectares, or 630 million hectares (1.6 billion acres). Again and not surprisingly, central Africa comes in second with 280 million hectares, according to the model, and industrialized nations will have an estimated 100 million hectares. The study also takes into account future technologies that will enable extraction of other useful products from energy crops. In fact, the ability to extract highvalue products first with the lower-value residues being used for energy production would most likely make energy crops more economic, it says.