Turning food into fuel is an odd idea—both on first and second glance. It takes a lot of fertilizer, effort, subsidies and land to make not much energy. The entire landmass of the US would barely produce enough corn to power its automobiles. Most studies show ethanol produces less harmful emissions than gas, but the benefit probably doesn’t outweigh the higher price of everything from bacon to burritos. This explains why energy giant BP and a host of start-ups are examining turning green muck into fuel.
Algae may be ickier than corn, but it has a number of advantages. It grows far faster, multiplying its weight several-fold in the course of a day. Theoretically, one acre of algae can produce 40 times the energy produced by an acre of corn. And it doesn’t need prime farmland—a brackish pool of water in a sunny area suits it just fine.
For all these benefits, green goo isn’t ready to take over the world. It can be fickle to grow. Crops can get infected with useless strains of algae. Separating the fuel from the water is difficult. And nobody in the field can agree whether it is better to grow dilute amounts of algae in cheap open ponds or concentrated amounts in expensive, closed areas.
Indeed, neither may work. Venture capitalist and green guru Vinod Khosla, for example, thinks the near-term economics of algae only work if one grows genetically modified strains in the middle of the ocean—a politically unfeasible idea.
But algae have an advantage that may eventually tip the scales; it needs lots of carbon dioxide (CO2) to grow fast. Start-up Greenfuel Technologies, for example, uses power plant emissions to boost the production of algae.
The company says this can cut CO2 emissions from a gas or coal plant by 80%. Indeed, US government researchers have said that algae may be the cheapest way to reduce pollution from coal. This would be a big advantage if the government imposes a carbon tax. Turning food into fuel doesn’t make much sense, turning waste into fuel does.