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The Week in Green Cars
Mike Millikin, 12 Dec 04

88mpg_sm.jpgEvery Sunday, Green Car Congress' Mike Millikin gives us an update on the week's sustainable mobility news. Green Car Congress is by far the best resource around for news and analysis covering the ongoing evolution of personal transportation. Take it away, Mike:

The tenth Conference of the Parties to the United Nations Framework Convention on Climate Change (COP-10) is underway in Buenos Aires. The US position on addressing climate change and not supporting Kyoto is outlined by the State Department here. The UNFCCC COP-10 official site is here.

During the workshop on mitigation at COP-10 this week, the representative from the US DOE outlined in his presentation the department’s strategy for transportation: short-term reliance on hybrids, long-term transition to hydrogen. The hydrogen part is no surprise—but I think this is the first time I’ve seen such a clear and strong endorsement by the US government of hybrids as the preferred short-term bridge technology.

In the same session, the representative from Brazil presented that country’s biofuels strategy. Brazil, with its already strong reliance on ethanol just announced a national Biodiesel Program. Although research is underway in the use of ethanol as a feedstock for the production of hydrogen, Brazil’s ongoing focus is on the use of biofuels as its carbon mitigation strategy.

Back in the U.S., automakers took their challenge to California’s right to regulate CO2 emissions from vehicles to Federal court this week. (GCC post.) The automakers charge that regulating CO2 emissions is simply another means of establishing fuel efficiency standards—and since regulating fuel efficiency can legally only be done for all of the US by the EPA, California does not have the right to establish standards for CO2.

California, for its part, does not mention fuel economy, but focuses on the deleterious effects of CO2 in accelerating climate change. Further complicating the issue, although California has the right to regulate its own air quality, the EPA does not recognize CO2 as a pollutant to be regulated.

This case and the separate lawsuit brought by seven states attorneys general and New York City against five big US power companies for creating a public nuisance with their greenhouse gas emissions (GCC post) may ultimately have impacts similar to that of the Scopes (Monkey) trial, in that what ultimately is at issue here is the scientific theory of climate change and the harm that climate change will cause.

First, there is no doubt that the amount of CO2 produced in an engine is directly correlated to the amount and chemical composition of the fuel burned. CO2 is a standard byproduct of the combustion equation. Some basic fuel chemistry is helpful as background.

Internal combustion engines convert chemical energy—the energy associated with the atomic bonds in a molecule—into mechanical energy through combustion. Combustion is a chemical reaction in which the fuel combines with oxygen (oxidation) to create new chemical structures, releasing a large quantity of energy in the process. Those new chemical products are the basis of the emissions from combustion.

A simplified basic ideal chemical reaction of combustion for engines using hydrocarbon fuels is:

Hydrocarbon fuel + Oxygen Carbon dioxide + Water + Heat
Cx Hy + a O2 b CO2 + c H2O + Heat

Chemical equations must balance, so the number and type of atoms with which you start must match the number and type of atoms with which you finish. In other words, the amounts of the products of the chemical reaction will depend on the composition and type of the original hydrocarbon fuel. Gasoline, for example, is a complex mixture of chemical additives and hydrocarbons of mostly four to twelve carbon atoms each. Natural Gas has a much simpler structure, consisting of one carbon atom to four hydrogen atoms (CH4). As a result, combustion of natural gas produces less CO2 than the combustion of an equivalent amount of gasoline.

This idealized view leaves out the messy questions of what happens to the nitrogen in the air (creates oxides of nitrogen), the unburned hydrocarbons, and toxic chemical byproducts. At a very basic level, the automakers have a point—regulating CO2 emissions will force either a reduction in fuel consumption or the use of alternative fuels.

There are other sources of CO2 and other greenhouse gas emissions from automobiles that could be controlled without touching fuel economy (air-conditioning, for example). But for the most part, reductions in CO2 will result in a mandate for decreasing fuel consumption.

That’s one of the reasons this is such an important case for both sides. If California prevails (or if the attorneys general prevail) it establishes CO2 as a new criteria pollutant to be regulated because of its harmful effect. That validation of the theory (especially anthropogenic causality) of climate change would have a profound impact on the auto industry, and on the timetable for moving to solutions for sustainable transportation.

Prevailing, of course, would be a terrific (and WorldChanging) step forward.

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