Wednesday, April 6, 2011

Energy Independence Part 3: Biofuels


Cellulosic Ethanol:
Around the country and especially in the Midwest, a number of proposed plants that would turn corn cobs, wheat straw and other plant-based feedstocks into fuel and sell it on the market are working to secure the last stages of financing, and some could become operational in the next few years. A smattering of smaller pilot plants are already operating, helping companies to hone the technology and economics of their product.

Four years ago, Congress ordered that 250 million gallons of cellulosic ethanol be produced in the United States in 2011. That would have equaled roughly 0.2% of the nation’s annual gasoline use, a small but measurable amount. Instead, after companies struggled to find capital during the economic downturn, federal regulators ratcheted down the expectations. Now, only 6.6 million gallons of cellulosic ethanol must be produced this year.

Federal officials have used a variety of tools over the years to promote ethanol, including mandated production goals. But many of these are increasingly controversial; the latest example was an E.P.A. decision in January to allow a 15 percent blend of ethanol into vehicles at least as new as the 2001 model. Ethanol makers sought this as a way to expand their market, but automakers resisted — and whether gasoline retailers will actually carry higher blends anytime soon remains to be seen.

Butanol:
Alternative fuels such as ethanol could help reduce carbon-dioxide emissions and decrease oil imports, but so far these biofuels only make up a small fraction of fuel use. One of the biggest challenges to ramping up ethanol use is distributing it. That's because ethanol can't be transported in the same pipelines used to distribute gasoline. What's more, ethanol delivers far less energy than gasoline does on a gallon-for-gallon basis.

Philip New, president of BP Biofuels, a recently created company within the giant British oil producer, thinks it has a solution: butanol. While butanol, like ethanol, can be made from corn starch or sugar beets, its properties are a lot more like gasoline than like ethanol. That means it can be shipped in existing gasoline pipelines. It's less corrosive and it contains more energy than ethanol does, which will improve mileage per gallon. Like ethanol, butanol is being considered as an additive to gasoline.

Biodiesel:
Biodiesel is made by combining alcohol (usually methanol) with vegetable oil, animal fat, or recycled cooking grease. It can be used as an additive (typically 20%) to reduce vehicle emissions or in its pure form as a renewable alternative fuel for diesel engines.

Research into the production of liquid transportation fuels from microscopic algae, or microalgae, is reemerging at National Renewable Energy Laboratory. These microorganisms use the sun's energy to combine carbon dioxide with water to create biomass more efficiently and rapidly than terrestrial plants. Oil-rich microalgae strains are capable of producing the feedstock for a number of transportation fuels—biodiesel, "green" diesel and gasoline, and jet fuel—while mitigating the effects of carbon dioxide released from sources such as power plants.

More information:
» DOE: Emerging Fuels at Early Stage of Development
» Improving Efficiency of Biofuel Production
» Carbon Capture and Sequestration

No comments: