Know your biofuel

April 3, 2013 - In the latest issue of Animal Frontiers, two chemists share the pros and cons of the different biofuels. In their paper, Roland Arthur Lee and Jean-Michael Lavoie explain that biofuels range from first-generation fuels, like ethanol made from corn, to third-generation fuels, like alkane made from algae.

Though biofuels are more renewable than fossil fuels, each type of biofuel comes with challenges:

First-generation biofuels

According to Lee and Lavoie, these are the only biofuels currently produced on an industrial scale. People are most familiar with first-generation biofuels in the form of ethanol. Ethanol is usually made from corn or sugarcane, but it can also be made from whey, barley, potato co-products and sugarbeets. Biodiesel is another first-generation biofuel.

First-generation biofuel production is controversial because it usually depends on plants also used for human and livestock foodstuffs. Prices for corn and sugarcane have gone up in many areas because of this competition.

On the plus side, first-generation biofuel production does leave co-products that farmers can use for livestock feedstuffs. According to Lee and Lavoie, these co-products are “a net asset for the whole economical balance of the process.”

Second-generation biofuels

These are more experimental. Scientists have found that some non-edible materials, like wood chips and municipal solid waste, can be converted into fuels like methanol.

There are two methods for making second-generation biofuels. In the “thermo” method, producers use heat to convert biomass into methanol or solid fuel, sometimes called Biochar. In the “bio” method, producers isolate cellulose from plant matter and break the cellulose into simple sugars.

Fuel quality is a drawback with some second-generation biofuels. One kind of fuel, biobased dimethyl ether (BioDME), has a lower viscosity compared with diesel fuel. This means it can cause more wear and tear on fuel injection systems. Price is another drawback. Though second-generation biofuels can be made with non-edible biomass, it is tempting to use more plentiful sources, like corn. Unfortunately, these sources are also more expensive. The enzymes used in the “bio” method can also be pricey.

Third-generation biofuels

Could your car run on algae? With third-generation biofuels, scientists hope to extract lipids from algae to produce a more sustainable fuel.

The microorganisms that make up algae are packed with lipids that can be converted into fuels like kerosene grade alkane. Algae also grows very quickly compared with biomass sources like corn.

One drawback to third-generation biofuel production is that algae require large bodies of water. This could be a major problem for countries like Canada, where temperatures drop below freezing for a good portion of the year. Lee and Lavoie also discuss the technical challenge of filtering the algae and extracting lipids.

Want to learn more about biofuels? You can read the full paper on “From first to third generation biofuels”

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Impact of biofuel production in Brazil on the economy, agriculture, and the environment