In bioenergy, it is often difficult to see the wood for the trees. The many articles about truths and myths do not really help. Meanwhile, biofuels are currently produced in volumes where they start to make a real contribution to energy security.
An ethanol boom in the USA has led to the production of 16 million cubic meters, primarily based on corn. Brazil has a longer tradition and currently produces 15 million cubic meters of ethanol, using sugarcane. In Europe, Germany is leading with a 2 million m3 production of biodiesel in 2005. Production cost for bioethanol has come down to 0.15 - 0.18 euro/liter (with one liter of ethanol equivalent to 0.67 l of gasoline in terms of energy content).
Are biofuels sustainable?
Well, they are definitely not energy or CO2 neutral. The ethanol production process is energy intensive, consuming almost as much energy as it produces. Depending on the carbon emissions of energy used in production, the net CO2 effect can be a fine balance, rising a lot of debate. B
iofarming has a large impact on the environment through its extensive use of herbicides and fertilisers. Biofuels require vast amounts of land, contributing to deforestation. The sugarcane harvest in Brazil is hard manual labor, not always under the best social conditions (although these stories have to be considered in the right perspective). Before the harvest, the fields are burned, causing large emissions of nitrous oxide and methane, both greenhouse gasses. Finally, where biofuel competes with food, for example through land use or raising food prices, it produces a terrible injustice. Therefore it becomes essential to separate food from biofuel feedstocks.
A first solution is cellulosic ethanol from fast-growing crops. Natural production of cellulose is 1,500 billion tonnes per year (1.5 E12 tonne). For US alone, it has been estimated that an annual cheap feedstock of 1.3 billion tonnes annually is available. This could displace about 40% of US oil consumption (currently at 20 million barrels per day).
According to NREL, cellulosic ethanol could supply 3.5 billion barrels per year, provided that a number of technological breakthroughs in efficient mass production can be realised. A second solution is fuel from algae. They produce oil naturally. Algae can grow in waste water or sea water. They can yield 1,000 - 20,000 gallons of oil per acre. Twenty million acres of algae farms (8 million hectares, or 80,000 square km, an area equivalent to Benelux, or 20% of Finland) could make the US independent from oil. However, a number of breakthroughs need to be realised. The LifeFuels consortium has a 4-year Manhattan project, though it's not fully clear what may be expected by 2010.
Biofuels are not the only game in town. Battery technology is developing fast, showing all-electric or primary-electric vehicles on the horizon. Alternatively, hydrogen might just develop into the fuel of the future, despite limited progress over the past 5 decades of research. Closing the circle, algae could also produce hydrogen. Therefore, quite a few risky bets with very high returns on the future of transportation. There need not be a single winner, although it's very likely that there are going to be some losers.