Biofuel Bonanza
Are all these alternative fuels really “green”?
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Biofuel Bonanza
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Hi there, and welcome to Make-it-Green Girl’s Quick and Dirty Tips for an Earth Friendly Life. One of the buzz-words both candidates are fond of in the 2008 US presidential election is “biofuels.” In this episode, find out what biofuels are out there, and what they might mean for the future of America’s energy economy.
There are three reasons our society should definitely consider biofuels, and at least one should resonate with you.
Reason Number 1 : The world is running out of cheap oil, which is the foundation of the global economy. Demand for fuel and power are rising, while oil discovery and production are falling. Without a substitute, the world may see a recession or straight-up depression as a result of linking our entire economy to one commodity — cheap oil. Think there’s plenty more oil out there and the end of oil is a myth?
Reason Number 2 : Burning fossil fuels is putting out more CO2 than the planet can keep up with, leading to acidifying oceans, rising sea levels, and global climate change. Even if there is plenty more oil, we should not be burning it. Don’t believe in global warming? How about this one?
Reasons Number 3 : The US imports 60 percent of our oil, mostly from countries with destabilized political structures and a nasty grudge against the US. If we want to be free of the control of those nations, we need to come up with a way to fuel ourselves.
Ethanol: Problems and Promise
Ethanol is the molecule that get’s you drunk at the end of the wineglass. Theoretically, today’s gasoline powered cars could run on pure ethanol, but since they’re optimized to run on gas, ethanol would destroy the engine. By contrast, newer flex-fuel vehicles are designed to run on a mixture of ethanol and gasoline, at any ratio.
Ethanol holds a lot of promise. It burns far cleaner than gasoline, producing less ozone, NOx, and particulate matter because of the extra oxygen in the ethanol molecule. It’s also a very high performance fuel, used in race cars for its excellent power profile. It can even be used to power airplanes.
Ethanol has a few problems, though. It has less energy per gallon than gasoline, which means you need more ethanol to drive the same distance. Car makers are using technology to close this gap, but we’re still a ways away.
Most ethanol is America is made from government-subsidized surpluses of cheap corn, but the way we do it barely makes enough fuel to cover the energy cost of growing and distilling the stuff in the first place. Plus, other crops are better at turning sun energy into ethanol feedstock, like sugar cane and switchgrass, a tall prairie grass native to North America.
Even agricultural waste like corn stalks and sawdust can be made into ethanol — the same microbe that helps termites eat your house might help us make fuel. Cellulosic ethanol is by far the most promising feedstock, with the most energy per unit energy going in, and the least impact on our land.
Biofuels in general also raise the food-to-fuel debate. Some economists believe corn and sugarcane diversion to ethanol causes increasing prices that hurt the poor and hungry trying to buy food.
Land use is also a problem. Rising prices of ethanol is encouraging farmers to dig up the rain forest and plant more sugar cane, which only contributes to global warming and the depletion of a precious biological resource.
We’ll work those kinks out in time, but for the moment it would be wiser to invest in ethanol research than ethanol production.
Biodiesel: Black Gold Turns Green
Rudolf Diesel, the German engineer who invented the engine that still carries his name, designed the machine to be a flexible alternative to expensive steam engines. He also designed the engine to run on a variety of fuels, including kerosene, gasoline, and peanut oil.
Diesel engines are attractive in tough times because not only is diesel fuel more energy dense, meaning you can drive farther on one gallon, but the engines themselves are more efficient. Diesel cars can get up to 40 miles to the gallon. Biodiesel’s energy density is comparable to petroleum diesel.
We decided to use petroleum because it was cheap and abundant, but petroleum isn’t so cheap anymore. Biodiesel is not pure veggie oil, though some folks are definitely running diesel cars on straight veg. Instead, biodiesel is made by reacting fats with wood alcohol or grain alcohol (ideally, made from renewable sources) so it will flow from fuel nozzles a bit better than veggie oil.
This is a ridiculously simple reaction, and many home chemists are doing it successfully. If you want to learn how to do it yourself, check out the references at the bottom of the transcript. No one can refine crude oil in their backyard, but biodiesel can be made successfully on almost any scale, creating opportunities for local distribution chains which are not as vulnerable to world oil prices.
Biodiesel can be made from any oil, from soybean oil to waste cooking oil to animal fat from the rendering industry. Of course the products that are already waste streams are the most attractive, but another promising feedstock is algae that can be grown in greenhouses on marginal land to produce more oil per acre than any crop can. This helps alleviate the guilt of diverting food crops into fuel streams.
With a few inexpensive modification, biodiesel can be used to fuel anything with a diesel engine — ships, cars, trains, trucks, portable generators, and home heating furnaces. Biodiesel is a great solvent, so it also cleans out your dirty diesel engine from all the grime, which is actually better for your engine than diesel fuel. But, you have to replace the exhaust filter a few times when you first use it. Plus, it will eat away at natural rubber hoses, so you have to make sure to use synthetic rubber when you run biodiesel.
Biodiesel runs cleaner than petroleum diesel, with the one exception of NOx emissions, which a catalytic converter should take care of. Plus, the exhaust of biodiesel smells like french fries!
Biomass: Poop Power
One last category of biofuels is made from solids collectively known as “biomass.” This is by far the most in need of research money, and the most promising, because it helps us reduce pollution by making power from our waste streams.
Human and animal wastes can be digested in the absence of oxygen to produce methane. This methane could then be burned in a power plant or driven in natural gas vehicles. I’m sure you’ve been behind one of those iconic brown UPS trucks that now say “Powered by Clean Natural Gas.”
Municipal solid waste and even hazardous medical waste like infectious tissue can be burned like any other fuel source to heat steam to turn a turbine engine. This generates electricity that could be used to power electric plug-in cars. Of course, the flame temperature of these plants has to be kept extremely high to avoid offgassing dangerous chemicals, and scrubbers are used in the exhaust vents to ensure no contaminants leave the plant.
Landfills produce methane naturally, so harnessing this energy seems like a bright alternative to allowing it to leak into the atmosphere — bad, methane is a greenhouse gas — or burning it in a flare at the landfill. So, instead of letting your trash rot in a landfill, wouldn’t it be cool if all our trash were power?
Conclusions
All of these biofuels are in their infant stages, especially the most promising renewable ones like cellulosic ethanol, algal biodiesel, and biomass. We’re never going to be able to replace our oil-driven economy with just one of these technologies. Each can by itself supply 15% of our fuel needs, at the most. But the need for diversity is a good thing, because if the whole switchgrass crop dies from disease, we won’t be totally powerless.
So, it’s time to invest in a little more research, a little less in subsidies, and make sure we’re taking care of our land. You can help personally by considering these issues carefully during the upcoming election, donating to universities and research organizations, and finding a favorite rainforest charity to volunteer for.
Resources
Biodiesel: Growing a New Energy Economy by Greg Pahl
From the Fryer to the Fuel Tank: The Complete Guide to Using Vegetable Oil as an Alternative Fuel by Joshua Tickell
Brock Biology of Microorganisms by Madigan, Martinko, Dunlap, and Clark
“Growing Fuel: The Wrong Way, The Right Way ” National Geographic, October 2007