The American Public Power Association recently submitted comments to the Environmental Protection Agency on its proposed rule to regulate nitrogen oxide emissions from stationary combustion turbines.
In its comments submitted to the EPA on April 15, APPA makes a series of recommendations, including:
• Exemptions for emergency CTs should be maintained, as proposed by EPA;
• Exemptions for certain low-emitting, non-major source CTs from Title V permitting requirements under Clean Air Act section 502(a) should be permitted; and
• The definition of “stationary source” should not be narrowed for the purposes of new source or reconstructed source analyses
In addition, APPA said that EPA’s chosen subcategorization by size, the medium and large CTs is appropriate – “however, further subcategorization by operational duties, exhaust temperature characteristics, and the function of natural gas-fired CT is more appropriate.”
APPA also said that EPA’s reference turbine is not representative and should be revised not artificially lower control technology cost projections.
The group also argued that the Proposed Rule should not regulate fuel oil and natural gas combusted at the same time, hydrogen co-firing is too nascent to support a standard with such limited data and alternative mass limits are unlawful due to the capacity factor restrictions that would result.
APPA also said that:
• Low load operation is essential; therefore, low load, non-SCR operation should be allowed to support grid flexibility;
• The proposed exclusion for combustion control technologies with SCR under part load conditions should be implemented;
• Emissions limits for baseload units should not be set at 2 or 3 parts per million (ppm), and a longer emissions averaging period is necessary (e.g., 30-day rolling average). A compliance margin is needed, and consideration of the emissions profiles of different types of CTs is important;
• Startup, shutdown, and fuel transition periods should be excluded from the emissions average for compliance; and
• SCR costs should be recalculated to reflect the current market and use a typically sized CT.
