Scientists have long known how to convert various kinds of organic material into liquid fuel. Trees, shrubs, grasses, seeds, fungi, seaweed, algae and animal fats have all been turned into biofuels to power cars, ships and even planes. As well as being available to countries without tar sands, shale fields or gushers, biofuels can help reduce greenhouse-gas emissions by providing an alternative to releasing fossil-fuel carbon into the atmosphere. Frustratingly, however, making biofuels in large quantities has always been more expensive and less convenient than simply drilling a little deeper for oil.
Ethanol, for instance, is an alcoholic biofuel easily distilled from sugary or starchy plants. It has been used to power cars since Ford’s Model T and, blended into conventional petrol, constitutes about 10% of the fuel burned by America’s vehicles today. Biodiesel made from vegetable fats is similarly mixed (at a lower proportion of 5%) into conventional diesel in Europe. But these “first generation” biofuels have drawbacks. They are made from plants rich in sugar, starch or oil that might otherwise be eaten by people or livestock. Ethanol production already consumes 40% of America’s maize (corn) harvest and a single new ethanol plant in Hull is about to become Britain’s largest buyer of wheat, using 1.1m tonnes a year. Ethanol and biodiesel also have limitations as vehicle fuels, performing poorly in cold weather and capable of damaging unmodified engines.
Tags: second-generation biofuel, biomass feedstocks, agricultural, waste, cellulosic ethanol, renewable diesel, jet fuels, gas, drop-in biofuels
Source: Economist, 2013-09-07.