The EPA has released its long-awaited proposed rules for the Renewable Fuel Standard, including calculations of the lifecycle greenhouse gas emissions for various biofuels. Unlike California, the EPA is proposing to “discount” the greenhouse gas emissions of both biofuels and the baseline petroleum gasoline. The discount rate that EPA uses for most of the calculations it presents is 2 percent over 100 years, although it also proposes using a 0 percent discount rate and a 30-year time span and is taking comments on other combinations. Biofuel critics immediately decried the use of the 100-year timeframe because the resulting calculation produces a better outcome for biofuels.
But the mere fact that it would consider measuring ethanol’s carbon impact over 100 years — or should we say guessing at it? — is evidence enough of the ethanol lobby’s stature.”
The EPA raised the possibility of computing greenhouse gas costs over a 100-year period instead of a 30-year period. The longer time frame would make the benefits of corn-based ethanol seem greater while discounting the initial costs, such as the loss of untilled land, over time. For example, the EPA said corn-based ethanol is 16 percent better than regular gasoline if its costs are calculated over 100 years, but 5 percent worse over 30 years.
‘EPA has left open the option that an exception to good science could be made in the case of a favored special interest,’ said Frank O’Donnell, who heads Clean Air Watch.”
Both biofuel supporters and detractors should be wary of these calculations and of the precedent they could set. It’s abundantly clear that few people understand what the numbers mean.
The timeframe being discussed is for application of a “foregone sequestration” penalty — the number of years that converted land is considered to be foregoing its preferred use for carbon sequestration as forest or grassland. This penalty is added over and above the initial assumed release of carbon from conversion of the land (and note that there is no comparable penalty for not leaving petroleum carbon “sequestered” underground). Under normal circumstances, industry would prefer a short timespan – fewer than 30 years. After this period, the land would be considered agricultural land rather than former forest and would no longer accumulate a carbon penalty.
The choice of a discount rate is intended to measure present day valuations of costs and benefits over time. So, what are the costs and benefits of reducing greenhouse gas emissions that EPA is discounting? In the analysis, it is the cost of converting forest and grassland to agricultural land in order to obtain the benefit of reducing greenhouse gas emissions from transportation in the future – the “payback”. What the EPA should have measured, though, is the cost of converting our petroleum-based system of transportation to a biomass-based one versus the benefits of reducing greenhouse gas emissions.
The results in the EPA’s proposed rule are skewed by two indefensible assumptions. First is the assumption that the baseline for greenhouse gas emissions from petroleum should be discounted. The law requires establishment of a baseline for gasoline in 2005. To apply a discount rate assumes that the baseline will improve by some rate of change over time. And since petroleum is not assessed a foregone sequestration penalty, the cost of taking carbon from well below ground and putting it into the air is essentially free.
A positive discount rate says that future reductions in greenhouse gas emissions are less important to Americans than the present day costs. Since EPA applies the discount to the petroleum baseline, it is in effect saying that Americans will care less and less about reducing greenhouse gas emissions over time if it means that they have to change their driving habits today. In other words, don’t worry, keep using petroleum and be happy.
Second is the assumption that biofuels are causing land conversion around the world and that the land conversion is always and everywhere accomplished by burning the ground cover and immediately releasing massive amounts of carbon. This unfounded and unproven assumption skews the results of the analysis to the point that the application of a highly unfavorable discount rate appears to benefit the industry and draws the wrath of environmental advocates.
But the reaction from O’Donnell and Carroll shows that biofuel opponents will decry any outcome as politics trumping science — unless it’s their politics that trump science.