Friday, May 20, 2011

Some thoughts on biofuels. . .

The main point to remember that we humans have to cut our CO2 down to about 1 ton per person if we want to avoid catastrophic global warming. That means we need to eliminate fossil fuels from our transportation system.

Now solar power and electric cars go a long way toward that goal, but they don’t get us all the way there. After 4 months of owning the Volt, we have driven 4,380 miles and used 45.5 gallons of gas—96 miles per gallon. Most of that gas was for a trip to San Diego in January. Since then, just driving around Oakland for 3,017 miles, we have used 13 gallons of gas for 233 miles per gallon. But the option to take longer drives is why we bought the Volt—it is nice to be able to make those occasional long distance trips that an all-electric car can’t do.

One solution to this problem of longer range driving is to build battery swap stations as envisioned by Better Place--
http://www.wired.com/autopia/2009/05/better-place/
However, this seems to me to be a long way off.

A more immediate solution is to run the cars on biofuels after the batteries have been run down. Biofuels (mostly alcohol and biodiesel) emit no net CO2 since the plants they are made from absorb CO2 while they are growing and then give it off when they are burned.

One of the most common criticisms of biofuels is that they will compete with land used to produce food, or that they will destroy forests that are already important carbon sinks. That’s what appeals to me about combining biofuels with the Volt. Since our overall mileage is around 100 miles per gallon, the total fuel needed is much less than if it goes into a conventional internal combustion engine car. For example, changing the fuel consumption for all cars from 20 miles per gallon (current average) to 100 miles per gallon would reduce total fuel needed by 80%, from 150 billion gallons to 30 billion gallons. Current alcohol production in the U.S. is about 7 billion gallons annually.

I’ve also been aware that alcohol as currently made from corn has only a modest (say 20%) reduction in greenhouse gases compared to fossil fuels because of the intense use of fossil fuels to grow the corn. However, sugarcane, as grown in Brazil, reduces greenhouse gases by nearly 90%, so that is a much more promising use.

Also, I’ve just been reading Alcohol can be a Gas, by David Blume, and it is providing me with a whole lot of new information. Here are some of the points I’ve been learning:
• The residue from distilling corn for ethanol—Distiller Dried Grains with Solubles/DDGS—is a very good food for cattle. And 87% of corn is used to feed cattle, so it doesn’t really compete with food production
• There are many crops that would be better for alcohol production than corn, especially if they are grown together. E.g. Sugar beets produce three times as much alcohol per acre and can be rotated with cassava and sugarcane.
• Given the predictions of increasing drought across the U.S. in the years to come, drought resistant plants are important to consider. For example, mesquite trees with an undergrowth of buffalo gourd could produce even more alcohol per acre than corn, in land that currently can’t be used for any other crop. Blume points out that an area the size of the Texas panhandle could provide 5.5 billion gallons of alcohol growing mesquite.
• Blume has many great ideas such as using cattails to treat sewage and transform that into alcohol.
• He also says that most cars can run on 50% alcohol, right now, with no conversion. I’m not ready to try that out on our new Volt, but it is interesting.

The holy grail of alcohol production is cellulosic alcohol—e.g. using the whole corn plant, rather than just the kernals. Cellulose can be any plant material from lawn clippings to municipal waste to wood chips. Blume argues that coppiced (aggressively pruned) red river gum trees could produce 2000 gallons of alcohol per acre. Advances have been made in distilling cellulose, but more government support is needed.

A company called Mascoma is planning to build a plant in upper Michigan that would produce 40 million gallons of alcohol per year from woodchips, harvested sustainably from the adjacent forest. Their CEO, Bill Brady, spoke to U.S. Senate Committee on Energy and Natural Resources on April 7, 2011 asking for loan guarantees, tax credits, and more flex fuel requirements. He pointed out that the U.S. spends $560 billion annually on importing oil—why not invest in an alternative. He claimed their alcohol would be competitive with oil at $75 per barrel. Since the current cost of oil is around $100 per barrel, that seems very positive.

I found it ironic that Valero was one of the investors in Mascoma. Valero, you may recall, was behind a ballot measure last November in California to try to derail the state’s global warming law. I was surprised to see them jumping into the cellulosic alcohol business—stay tuned.

Another big attraction of biofuels is that they can take care of the 40% of transportation that is not cars and light duty vehicles--big rig trucks, airplanes, trains, & boats. This would get us another 10% closer to our goal of eliminating CO2 sources (Transportation is 28% of all CO2 emissions; 40% of 28% is 11%--source: Moving Cooler published by the Urban Land Institute, citing the EPA)

This discussion of biofuels is to suggest that those of us supporting solar power and electric cars need to build alliances with the farmers and industries in the biofuels arena. I was disheartened to see some very hostile exchanges between the Renewable Fuels Association and the Environmental Defense Fund. I’d like to think were in this together—we need to find alternatives to fossil fuels. Constructive criticism is always important, but let’s not treat each other as the enemy.

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