Computers, Society, and Nature

Let’s do some math.

How can we aim to get carbon-free energy for the least amount of all-inputs-considered?

One exciting sector in energy is the BioFuels explosion (figuratively speaking, of course). These fuels derive from plant and vegetable matter. They produce energy from breaking down the matter in combustion, but with negligable emissions. Coupling this with the notion of capturing already-available sources of fuel instead of letting them become a waste issue is an attractive concept.

Consider this idealized view:

However, the numbers are not adding up as many speculate. With BioFuels, it seems the sustainable cards cannot be played – it may not even exist.

Producing ethanol and biodiesel from a variety of crops is just not worth the effort, so much so that it plain hurts. Some math:

In terms of energy output compared with energy input for ethanol production, the study found that:
— corn requires 29 percent more fossil energy than the fuel produced;
— switch grass requires 45 percent more fossil energy than the fuel produced; and
— wood biomass requires 57 percent more fossil energy than the fuel produced.

In terms of energy output compared with the energy input for biodiesel production, the study found that:
— soybean plants requires 27 percent more fossil energy than the fuel produced, and
— sunflower plants requires 118 percent more fossil energy than the fuel produced.

“Ethanol production in the United States does not benefit the nation’s energy security, its agriculture, economy or the environment,” says Pimentel. “Ethanol production requires large fossil energy input, and therefore, it is contributing to oil and natural gas imports and U.S. deficits.” He says the country should instead focus its efforts on producing electrical energy from photovoltaic cells, wind power and burning biomass and producing fuel from hydrogen conversion.

This quote and the above numbers come from a July 1, 2005, study at UC Berkeley.

Undetterred (as well they should be), environmental scientists concerned with righting this energy imbalance have been cutting as many corners as possible. Within this panorama article, mention of the many process steps and treatment applications come under scrutiny. Much work has been done, however, to roll many steps into one, for example, having on talented biotic enzyme do more than its share of chores, reducing the energy input required to churn out fuels.

The argument that neither biomechanically- or thermochemically-produced biofuels can compete with standard fuels is still contended, however, by some that say the math hasn’t been honestly calculated. The UC Berkeley mention builds on what Dr. Pimentel, Cornelle University, has produced, which has been criticized for using out-of-date data on the inputs necessary for fuel production.

Of course, it’s not all about the simple ‘energy math’. Consider the cropland which would supply all the biomass. Whole-sale growing of corn or any other single crop, according to Erich Pica of Friends of the Earth, requires pesticides and fertilizers that can find their way into the environment in water runoff from the fields. Replacing the entire U.S. fuel supply with corn ethanol would require at least 60 percent of the nation’s available cropland, according to calculations by Marcelo Diaz de Oliveira of the University of Florida.

This entry was posted on Thursday, October 6th, 2005 at 2:45 pm and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.