ISO New England has just released its Electric Generator Air Emissions Report for 2011. The bottom line?
- Total emissions of NOx, SO2, and CO2 have decreased by 12.1%, 29.5%, and 10.2% from 2010 to 2011
- Emission rates for NOx, SO2, and CO2 have decreased by 8.7%, 25.8%, and 5.9% over the same time period
As our observant readers will have inferred, ISO reports that total energy generation was down by 4.6% from 2010 to 2011. ISO attributes most of the emissions decrease to an increase in gas-fired generation and a corresponding decrease in coal- and oil-fired generation. According to the ISO, coal consumption fell from 6.2 million tons to 3.0 million tons from 2010 to 2011, and residual oil consumption feel from 1.5 million barrels to 0.7 million barrels over the same period.
Taking a longer time horizon, the emissions decreases are more substantial, though CO2 decreases are not as great as those for NOx and SO2.
- Total emissions of NOx, SO2, and CO2 have decreased by 58%, 71%, and 11% from 2001 to 2011
- Emission rates for NOx, SO2, and CO2 have decreased by 60%, 73%, and 16% over the same time period (For reasons unknown to me, the ISO-NE reports the rate comparison for 2011 to 1999, but I have used 2001 as the baseline to make it apples to apples with the total emissions comparison)
The explanation for the decrease over the longer term? “Increased use of new, more efficient natural-gas-fired power plants, a decline in the cost of natural gas, and the implementation of emission controls on some of the region’s oil- and coal-fired power plants.”
Sounds like a success story to me. This blog is temporarily a sarcasm-free zone.
These types of emissions reductions were put forth as a major argument in favor of the several gas-fired capacity proposals before the Siting Board (and in MEPA review) in the late 1990s and early 2000s. In particular, proponents documented the significantly lower sulfur content of the available gas compared to the coal and oil it would displace. Trying hard to remain sarcasm free, we should not be too surprised that CO2 emissions didn’t decline as much as the other parameters. After all, one of the standard approval requirements in the air permits for this new capacity was the use of catalysts to control CO by oxidizing it to CO2.