How green, really, is corn ethanol? It depends how you count.
It’s anything but an academic question—it could determine, in part, how America fuels its cars in the future.
The Environmental Protection Agency dealt a big blow to the ethanol industry earlier this year when it decreed that the corn-based fuel doesn’t have a much better carbon footprint than gasoline made with crude oil.
Ethanol producers have since regrouped and are striking back by taking a page from the EPA’s playbook.
The EPA, charged by the U.S. Congress with calculating carbon pollution from fuels, maintains that the ethanol industry is responsible for more than just the emissions generated from producing ethanol and burning it in vehicles.
Ethanol could have another environmental impact. That is, by taking corn out of the global food supply, ethanol producers are indirectly inducing people in other places, such as the Amazon rainforest, to clear forests to plant more crops to replace the lost corn. The kids call it “indirect land-use changes.”
Now the ethanol industry is saying oil-based gasoline has its own indirect effects in places like Canada’s oil sands, where oil companies burn through massive amounts of energy to extract and refine gunky oil.
In a recent report, the Renewable Fuels Association, ethanol’s main industry trade group, argues that the corn-based fuel’s environmental credentials should be measured against gasoline made with that kind of oil, not with the lighter and more easily refined crude grades, which are becoming scarcer. That comparison makes ethanol look a lot greener.
“If you’re going to be counting the angels on the head of a pin with ethanol at least take a cursory look at the impacts of petroleum,” says Bob Dinneen, president and chief executive of the group.
The issue is far from settled—the EPA is waiting for public comment before making its final determination – but discussions around it raise questions about how to extricate the real carbon footprint of a fuel from a complex web of interconnections across continents. Where do you begin? Where do you finish?
Do you, for example, count the carbon footprint of the tire on the tractor that harvests the corn field, which is probably made with synthetic materials whose origins can be traced to natural gas or oil, and which may have been transported to the U.S. from the Middle East in a ship powered by oil-based fuel?
No, say emission-counting experts, which usually abide by ISO standards when conducting a life-cycle assessment, the practice of sizing the environmental impact of a product. How about the fuel to power the tractor? Yes.
Still, there is enough unresolved wiggle room for companies to find the methodology that shows their products in the best light. For example, what portion of the emissions generated by producing ethanol should be assigned to the leftovers of the process, which are used as cow feed? The more you chalk up to the feed, the better ethanol looks, says Roland Geyer, a life-cycle assessment expert at University of California, Santa Barbara.
This is the kind of minutiae the government will have to resolve if it wants to cut this particular Gordian knot.
“There’s no way around it because we are entering into a world of different power trains—pure gasoline, pure battery, electric plug-in hybrids, fuel cells,” says Mr. Geyer. Without proper accounting, “we just can’t just compare.”
Maybe it would be easier to just count angels dancing on the head of a pin.