The large-scale CO2 reductions envisioned to stabilize, and ultimately reverse, global atmospheric CO2 concentrations present major technical, economic, regulatory and policy...
A Multi-Pollutant Strategy
An integrated approach could prove more effective for controlling emissions.
In response to the Court’s decision on CAIR, EPA is pursuing action through all three branches of government—judicial, legislative, and regulatory. Whatever the forum, EPA is committed to working expeditiously with states and other stakeholders to get back on track towards efficient, effective means to reduce power-sector emissions and achieve the health and environmental goals of the Clean Air Act. Some of the major lessons gleaned from our experiences can help efforts progress.
Lesson 1: There is great value in a multi-pollutant control strategy, but significant challenges remain to reach agreement. Although we have noted the many advantages and the broad general support afforded the integrated concept, parochial issues of different groups hinder efforts toward a Congressional and/or regulatory solution. Persistent areas of contention encountered to date are: Whether CO 2 belongs in a multi-pollutant control program (at least, now); whether mercury should be traded; and whether certain provisions of the current CAA should be streamlined in response to large emission reductions provided by emission caps?
With that in mind, stakeholders should not let the perfect be the enemy of the very good. All the SO 2 and NOx emissions under the alternative proposals are much lower than current levels, and resolution of these differences is not insurmountable.
Lesson 2: Coal-fired generation is very resilient. When it comes to controlling SO 2, NOx and mercury, EPA repeatedly has found that coal-fired generation can achieve significant reductions and still compete effectively, given its relatively low operating costs compared to generation from other fossil fuels, nuclear and renewables. 13 Until fairly recently, when significant CO 2 reductions were added to the mix, the dynamic changed and coal-fired generation became less attractive. 14 However, more recent analyses have suggested that clean-coal technologies, including IGCC and carbon capture and sequestration, could allow coal-fired generation to remain competitive even with significant CO 2 reductions. 15 As capital costs for new generation technologies continue to increase, efficient existing coal also remains cost competitive depending upon the stringency of required CO 2 reductions.
Lesson 3: SO 2 reductions deliver the biggest bang for the buck. Most of EPA’s benefits analysis have focused on PM2.5 and ground-level ozone benefits due to SO 2 and NO x emission reductions, with only limited attention to the benefits for mercury and CO 2 reductions (due to the complexities of quantifying CO 2 and mercury benefits). As part of EPA’s 2005 assessment of CAIR and related multi-pollutant legislative proposals, the agency found that with respect to reducing PM2.5, a ton of SO 2 emissions reduced from electric power generation has over seven times the benefit of a ton of NOx emissions reduced. 16 According to additional analysis, 87 percent of the total PM2.5 benefits can be attributed to reductions in SO 2 emissions. Further, the average health benefit associated with each ton of SO 2 reduced is nearly $12,000 per ton. 17 Notably, the benefits for reducing emissions affecting highly populated urban areas are greater, and smaller for less populated areas.
Lesson 4: Co-benefits from pollution controls can be very meaningful for mercury reductions.