Because of the change in PSD permit requirements for GHGs based on Utility Air Regulatory Group v. EPA, early implementation of the GCCS as BACT will not be required. For the Florida landfill described in the case study, above, the fugitive methane emission rate was estimated to be well over 100,000 tons CO_2e per year before the installation of GCCS. Currently, there is a lag of five years after placement of waste before a landfill is required to expand their GCCS to cover that waste. As part of a routine review and update of NSPS rules, EPA proposed a new rule for MSW landfills (79 FR 41796). In this proposed rule, EPA decided against changing the lag time for requiring the initial installation and expansion of GCCS. EPA presents in the proposed rule that the emission reduction is 27% higher with a shorter lag time during the last year of a 10-year analysis but over the 10-year analysis period, the emission reduction is only 8% higher with the shorter lag time.1 The analysis assumes a lag time of four years as the baseline, which is shorter than the regulatory requirement. Since voluntary early installation of GCCS cannot be controlled, a greater and definite emission reduction is achieved when five years is used as the baseline.8 EPA acknowledges that more emission reductions may be achieved by requiring earlier installation of GCCS, especially in wetter climates where early installation is already in practice for odor control and energy recovery and for smaller landfills that are currently not required to install GCCS. In addition to the variability of emission impact from year to year, EPA anticipates higher installation and maintenance costs for landfills to install smaller GCCS more frequently and potentially in areas closer to active areas of the landfill. Therefore, EPA did not propose requiring earlier installation of GCCS in their proposed NSPS.1 Beyond regulatory requirements, landfill gas is often collected to control odor, for electricity (and heat) generation, for use as fuel, to minimize fire and explosion hazards, and for tax or carbon credits. However, there are limited carbon credit incentives: the California cap-and-trade program does not accept landfill gas projects and the Regional Greenhouse Gas Initiative market does not offer a competitive market for offset projects at the moment. Landfill gas to energy projects can be costly and may even result in a net loss for some landfills with no previously installed GCCS. Currently there is a lack of economic incentive for earlier installation of GCCS. However, there is potential for reducing methane emissions further during the first five years of waste placement before it is regulated. The EPA offers a voluntary assistance program called the Landfill Methane Outreach Program that provides technical resources to help landfill gas to energy projects. If regulations do not shorten the lag time, additional economic incentives are needed to help promote methane emissions reduction during the lag time.
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