06.02.08

Burning question

Posted in Energy, Society at 13:39 by RjZ

General Motors has spent piles of money on it’s questionable advertising campaign “Live Green, Go Yellow” to promote the use of renewable bio-fuels. When I ‘go yellow’ it’s usually a hint that I am not drinking enough water, but whatever. My real question is does using bio-fuel help reduce carbon?

Coal, oil, and other fossil fuels are really just stored solar energy. Hydrocarbon bonds built up in plants with the help of the sun and photosynthesis are dried and compressed into coal, or eaten by dinosaurs first, then compressed into oil. We dig it up and burn it, breaking down those hydrocarbons into CO2 and water, for energy. We get so much energy to fuel our economy and way of life simply because so many years of solar energy is stored in that compressed fossil fuel.

Bio-fuels, meanwhile, are considered renewable because while growing they were busy absorbing CO2 and when we burn them, it’s simply released again—net zero CO2, or so the marketing hype goes. It comes down to this: as long as we don’t burn these bio-fuels any faster than it takes to grow them, we’ll have a completely renewable, and carbon neutral source of energy. An energy source that, by the way, is essentially just solar power stored in hydrocarbons by the plants.

It’s ridiculous to imagine that we can suddenly get by with the solar energy stored in plants (or even algae) when we’ve been burning through our compressed, energy dense fossil fuels like there’s no tomorrow! Actually, it takes quite a bit of fossil fuel to grow a plant these days, whether it’s a tree or switch grass as President Bush recommended, there are fertilizers, tractor fuel, and diesel fuel to carry it to the point of use (whether that’s your home or a centralized power plant.)

I’d be unfair if I said there were no advantages to renewables. There is, for example, energy independence and reduced CO2. Using ethanol to supplant oil gives the United States (or any other nation) more political independence to negotiate with countries whose behavior they may not agree with but from whom we’re currently buying critical energy. Using renewables certainly does reduce the amount of CO2 released from all that coal and oil (it was all previously stored, as opposed to being stored slowly over the last season it took to grow the crop—it’s just too bad it will only last a few minutes to extract the energy stored there). Plants are also remarkably efficient at turning solar energy into hydrocarbons, so long as they’re allowed their sweet time to do it.

Unless we can figure out a way to use energy as slowly as the plants did, we’d better keep looking for a real solution, and I’ll leave the going yellow to the bathroom.


Update: It’s worse than I thought. This article sites three folks from three different disciplines; an economist, scientist and environmentalist. They’re not so up on the bio-fuel idea either. I agree with the idea that locally, if it’s sustainable; for example if you’re burning all your bio-waste that would just go into a landfill (which by the way is a form of carbon sequestration!) there might be some point to burning bio-fuels. Aside from that, I am scared of people cutting down forests just to plant switch grass.

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