See the review of the basic parameters for the new carbon standard.

 

THRESHOLDS

 

Environmental Protection Agency (EPA) Standards of Performance for Greenhouse Gas Emissions for New Stationary Sources: Electric Utility Generating Units (EGU) represents the first-ever limit on greenhouse gas emissions in the United States that would require new fossil fuel-fired EGUs greater than 25 megawatt electric (MWe) to meet an output-based standard of 1,000 pounds of CO2 per megawatt-hour (lb CO2/MWh), based on the performance of widely used natural gas combined cycle (NGCC) technology.

 

It may be useful to recall in this place that the average US natural gas plant, which emits 800 to 850 pounds of CO2 per megawatt, meets that standard; coal plants emit an average of 1,768 pounds of carbon dioxide per megawatt.

 

New coal-, coal refuse-, oil- and petroleum coke-fired boilers and IGCC units should also be able to meet the new standard, however, by employing carbon capture and storage (CCS) technology.

 

APPLICABILITY TO NEW SOURCES ONLY

 

The EPA new requirements are strictly limited to new sources and stopped short of imposing any restrictions on the US existing coal-fired fleet.

 

ALTERNATIVE OPTION FOR COMPLIANCE

 

New coal-fired or pet coke-fired units could meet the standard either by employing carbon capture and storage (CCS) of approximately 50% of the CO2 in the exhaust gas at startup, or through later application of more effective CCS to meet the standard on average over a 30-year period.

 

According to EPA the 30-year averaging option could provide flexibility for owners and operators of coal or pet coke units implementing CCS at the outset of the unit’s operation that were designed and operated to emit at less than 1,000 lb CO2/MWh to address startup concerns or short term interruptions in their ability to sequester captured carbon dioxide.

 

Coal- and pet coke-fired EGUs that use this compliance alternative must meet an immediate performance standard of 1,800 lb CO2/MWh (gross) on a 12-month annual average basis, which can be achieved by a “supercritical” efficiency level, during the period before installation of CCS.

 

By no later than the beginning of the 11th year, the facility would be required to meet a reduced CO2 emission limit of no more than 600 lb CO2/MWh (gross) on a 12-month annual average basis for the remaining 20 years of the 30-year period, such that the weighted average CO2 emissions rate from the facility over the 30-year time period would be equivalent to the proposed standard of performance of 1,000 lb CO2/MWh.

 

TRANSITIONAL RULES

 

EPA is not proposing standards of performance for existing EGUs whose CO2 emissions increase as a result of installation of pollution controls for conventional pollutants, or for proposed EGUs, which are referred to as transitional sources, that have acquired a complete preconstruction permit by the time of this proposal and that commence construction within 12 months of the EPA proposal.

As a result, those transitional sources would not be subject to the standards of performance proposed in the rules.

 

Approximately 15 proposed EGUs have received permitting authority approval for their preconstruction permits, but may not have “commenced construction” by the date of the proposed rulemaking.