February 10, 2008
Sustainable Living: Great green fuels: algae and switchgrass
by Shawn Dell Joyce
“Biofuel” is a catch-all term used to describe any number of plant-based sources of energy. Biodiesel is a biofuel that can be made from corn, soy, rapeseed, palm oil, switchgrass, sunflowers, flax, even algae, and many other organic waste materials.
Pure vegetable oil from restaurant fryers can be — and often is — used in diesel engines, with very little processing. In fact, Rudolph Diesel, the inventor of the diesel engine, powered his prototype with peanut oil in 1893. Diesel fully expected that all engines would be powered by biofuels.
In a 1912 speech, he said, “The use of vegetable oils for engine fuels may seem insignificant today but such oils may become, in the course of time, as important as petroleum and the coal-tar products of the present.”
Diesel died in 1913 under mysterious circumstances, and shortly after his death, petroleum began to replace vegetable-based sources of diesel.
Biofuels not the perfect solution
Today, as the world searches for solutions to greenhouse gas emissions, there is renewed interest in biofuels and diesel engines. Biofuels are being touted as a solution to American dependence on foreign oil and a green alternative to gasoline. But they are not the perfect solution.
Some biofuels might produce less greenhouse gas emissions than petroleum-based fuels. But it might require more fossil fuels to create that biofuel than using what that fuel saves.
“Different biofuels vary enormously in how eco-friendly they are,” says Dr. William Laurance, a staff scientist at the Smithsonian Tropical Research Institute.
“We need to be smart and promote the right biofuels, or we won’t be helping the environment much at all.”
The environmental cost of corn
The U.S. derives most of its biodiesel supply from corn, which offers the least oil (18 gallons per acre) of any biodiesel crop, and is the most environmentally destructive. Our corn harvest will be 335 million tons this year. About 85 million tons of this will be converted into ethanol. The rest will be used for sweeteners and as feed for livestock. To grow all that corn will tie up more than half of our farmland and fresh water and will dump millions of tons of fertilizers and pesticides into our ecosystem.
“Biofuel from corn doesn’t seem very beneficial when you consider its full environmental costs,” says Laurance, who recently authored a report about the rainforest destruction caused by growing corn and soy for biofuels.
“American taxpayers are spending $11 billion a year to subsidize corn producers — and this is having some surprising global consequences,” he says.
“Amazon fires and forest destruction have spiked over the last several months, especially in the main soy-producing states in Brazil.
“Corn (and soy)-based ethanol is supposed to reduce greenhouse gases, but it’s unlikely to do so if it promotes tropical deforestation — one the main drivers of harmful climate change.”
Converting our food crops to fuel for automobiles has moral implications in a world full of starving nondrivers. The World Bank estimates that the amount of corn needed to fill up an SUV is enough to feed a hungry person for a year. Do we really want to burn someone else’s dinner in our gas tank?
More environmentally friendly alternatives would involve using plants that don’t take up productive farmland or require fertilizers and pesticides. One example would be algae, which produces more than 1,000 gallons per acre of usable oil, making it the greenest choice.
GreenFuel is a company that grows algae in smokestacks of power plants to help clear emissions. Algae can be used twice. First, it can filter out 40 percent of carbon emissions from the coal-burning smokestacks. Then, the oil it contains can be used as biodiesel fuel. This double use means that algae grown on a typical 1,000-megawatt power plant could also produce 40 million gallons of biodiesel and 50 million gallons of ethanol, in addition to cleaner air and electricity. When you consider that we have more than 1,000 power generators in our country capable of being converted to algae farms, you see that algae could potentially meet current U.S. oil demands.
Another non-food fuel source is switchgrass, a native plant of the tall grass prairies. It grows 12 feet tall in one season and produces 10 tons of plant material an acre. Switchgrass can be pelletized and burned for home heating, as farmer John Brown in Orange County is doing. Or, it can be processed into ethanol, making more than 320 gallons of usable oil per acre. This is twice as efficient as corn or soy. Switchgrass can be grown on marginal soils, so it won’t displace food crops. It also provides wildlife habitat, and requires little use of fertilizers, insecticides or irrigation. Switchgrass-derived biodiesel can bring the cost of ethanol down to $1 per gallon at the pump.
Shawn Dell Joyce is the founder of the Wallkill River School and an
author of Orange County Bounty local foods cookbook.