Saturday, August 18, 2007

Biofuels, Meet Opportunity Cost

Posted Thursday at New Scientist is a report of this article in Science magazine. Here's the intro:

It sounds counterintuitive, but burning oil and planting forests to compensate is more environmentally friendly than burning biofuel. So say scientists who have calculated the difference in net emissions between using land to produce biofuel and the alternative: fuelling cars with gasoline and replanting forests on the land instead.

They recommend governments steer away from biofuel and focus on reforestation and maximising the efficiency of fossil fuels instead.

The reason is that producing biofuel is not a "green process". It requires tractors and fertilisers and land, all of which means burning fossil fuels to make "green" fuel.

The ultimate irony would be chopping down forest land to plant biofuel crops. Consider the following:
The researchers also compared how much carbon would be stored by replanting forests with how much is saved by burning biofuel grown on the land instead of gasoline.

They found that reforestation would sequester between two and nine times as much carbon over 30 years than would be saved by burning biofuels instead of gasoline (see bar chart, right). "You get far more carbon sequestered by planting forests than you avoid emissions by producing biofuels on the same land," says Righelato.

He and Spracklen conclude that if the point of biofuels policies is to limit global warming, "policy makers may be better advised in the short term to focus on increasing the efficiency of fossil fuel use, to conserve existing forests and savannahs, and to restore natural forest and grassland habitats on cropland that is not needed for food."

They do admit, however, that biofuels made from woody materials such as prairie grasses may have an advantage over reforestation – although it is difficult to say for now as such fuels are still in development.

Putting energy reform in the hands of domestic agricultural producers seems like no better an idea than putting it in the hands of domestic petroleum producers.


Lord said...

This is not unexpected. All changes we make have consequences about which we have only the dimmest impressions. Reforestation only goes so far though. Once mature, it must be harvested and stored to allow for more growth. Fires would be worse for the same reason.

Domestically it is more likely a question of crops vs pasture so it is unlikely to have the same effect and while biofuels are not green currently, there is no reason they cannot be green in the future. While it stresses food prices, it is unclear how much this is adjustment and how much permanent.

Rather than any global solution, this is better viewed as a local solution decoupling local economies from vagueries of volatile politically controlled resource markets.

Anonymous said...

The mistake in your analysis - as it is the case in Science's article - is to generalize from the unfeasible corn-made biofuels. Results would be different if the possibility of importing sugar cane-based biofuels from developing countries had been taken into account.

Andrew Samwick said...

I'd like to see that analysis as well, and when I refer to "domestic agricultural producers," I'm including the sugar lobby as well as the corn lobby.

As the prior comment notes, the "chopping down forests" strategy is not likely to be a concern in the U.S. But it is very much a concern in Brazil and other places from where we would be importing sugar cane-based biofuels.