Key words :
Counting All the Carbon
7 Nov, 2009 04:00 pm
Last Thursday, an editorial in the Wall St. Journal referred to a paper in the latest issue of Science entitled, "Fixing a Critical Climate Accounting Error", which concludes that the manner in which the greenhouse gas impacts of biofuels are currently assessed fails to account for significant emissions that occur outside the envelope normally drawn around an ethanol or biodiesel plant and the farms that supply it with feedstock. And if that omission weren't glaring enough, I ran across another instance in which regulators appear to be turning a blind eye to the full impact of another popular option for addressing climate change, electric vehicles.
The report provides further evidence that it's no longer appropriate to assume that just because the carbon embodied in biofuels such as ethanol originated in green plants that absorbed it from the atmosphere, they must therefore be "carbon neutral"--other than the emissions from fossil fuels used in the cultivation, harvesting and transportation of the crops from which they are produced, along with the energy used in their processing. Additional emissions apparently result from the global displacement of the crops turned into energy here, and in some cases those emissions are on a similar order of magnitude to the direct emissions from the combustion of the biofuels--combustion that has gotten a free pass until now.
This is a highly inconvenient result for those engaged in the production of biofuels from food crops, on two levels. First, it puts the climate change justification for the subsidies and mandates responsible for the rapid ramp-up of conventional biofuel production in question. Second, the source of this doubt is no less than one of the same scientific journals in which so much of the peer-reviewed science contributing to the oft-cited scientific consensus on climate change has appeared, and subject to the same level of scientific scrutiny. Casting doubt on the source of this unwelcome message thus risks casting doubt on the entire edifice upon which the current, much-expanded biofuel endeavor rests.
Let's be clear that I don't blame the biofuel industry for promoting a product that many thought would help, but may ultimately turn out to do little or nothing to reduce the greenhouse gas emissions implicated in climate change, any more than we should blame the producers and consumers of fossil fuels for their contribution to the accumulation of those gases before the current consensus on climate change emerged. (I confess that I regard attempts to portray that consensus as having existed as long as 40 years ago as the worst kind of revisionism, since the creation of the consensus depended not on a few key insights, which might have turned out to be wrong, but on mounting evidence from the steady accumulation of peer-reviewed research during that interval.)
Having said that, I have a much harder time understanding the inclusion of an equally serious--and apparently entirely conscious--omission in the new automotive fuel economy and emissions standards jointly developed by the Environmental Protection Agency and the Department of Transportation. I had occasion to browse through the agencies' proposed text and was startled to see that for purposes of calculating carmakers' fleet CO2 emission averages, it assumes that electric vehicles (EVs) and the electric usage of plug-in hybrids (PHEVs) have zero lifecycle emissions. Not only that, but the proposed regulation would count each EV as if it replaced two other emitting cars: thus, zero GHG impact not once but twice. Even the authors admit that this is false, and here I must quote,
"EPA recognizes that for each EV that is sold, in reality the total emissions off-set relative to the typical gasoline or diesel powered vehicle is not zero, as there is a corresponding increase in upstream CO2 emissions due to an increase in the requirements for electric utility generation. However, for the time frame of this proposed rule, EPA is also interested in promoting very advanced technologies such as EVs which offer the future promise of significant reductions in GHG emissions, in particular when coupled with a broader context which would include reductions from the electricity generation. For the California Paley 1 program, California assigned EVs a CO2 performance value of 130 g/mile, which was intended to represent the average CO2 emissions required to charge an EV using representative CO2 values for the California electric utility grid."
But while I appreciate the agencies' rationalization that EVs and PHEVs might be counted as having zero emissions on a purely temporary basis in order to provide incentives for carmakers to accelerate their introduction, I'm also painfully aware that other such "temporary" measures have persisted long after the original justification for them had become obsolete--and here I can't help but think of the ethanol blending credit that is now in its 31st year.
Why do these loopholes in the way we tally greenhouse gas emissions matter enough for me to hammer away at them like this? Consider the proposed vehicle rules. By ignoring emissions that occur outside these vehicles, the government is discouraging carmakers from using less exotic technologies that might actually deliver comparable savings of fuel and emissions sooner, and at a lower cost to taxpayers and consumers. A conventional Toyota Prius hybrid running on gasoline emits only 10% more grams of CO2 per mile than California claims for an EV powered by its greener-than-average state electricity mix. Since the same number of batteries could equip many more Prius-type hybrids, at a much lower cost per car than for a full EV, the benefits of rushing EVs into production seem much less compelling at this point, particularly when the government is also subsidizing the purchasers of EVs and PHEVs to the tune of many thousands of dollars per car. That will amount to billions of dollars of extra subsidies for an incremental emissions benefit that might just be negative for an EV recharged using coal-fired power.
"Start as you mean to go on," goes the old saying. We know that whatever their energy security benefits and general hi-tech niftiness, EVs are not zero-emission vehicles, just as we now understand that it is likely that burning corn ethanol releases roughly the same level of greenhouse gases as the gasoline it is intended to replace. If cap & trade bills such as Waxman-Markey and Kerry-Boxer are to have any integrity as tools for achieving genuine reductions in the global greenhouse gas emissions behind global climate change, then we must count all the emissions from all sources, no matter how politically unpalatable that may be. EPA and DOT might do well to heed this advice, too, before establishing a new, impossible-to-revoke entitlement for the manufacturers of electric vehicles.
Originally published on Energy Outlook