Q688. Does the 25,000 ton CO2e per year limit (threshold) apply to the compressors individually, or in aggregate (all such compressors or equipment at the mine)?

A688. The subpart C reporting threshold, as defined in 98.2(a)(3), is an aggregate threshold, so it would apply to the total stationary combustion emissions of the facility (and assumes 98.2(a)(1) and (2) do not apply to the facility). If the facility meets the subpart FF threshold, as defined in 98.2(a)(1), all onsite stationary combustion sources would be subject to the requirements of subpart C, regardless of emissions level.