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EPA Proposes Carbon Dioxide Standards for Existing, Modified, and Reconstructed Power Plants

Posted Wednesday, June 11th, 2014

In accordance with President Obama’s Climate Action Plan, the U.S. Environmental Protection Agency (EPA) has released two proposals regulating carbon dioxide (CO2) emissions from power plants. The first proposal provides CO2 “Emission Guidelines” for existing electric generating units (EGUs). The second proposal provides CO2 performance standards for modified and reconstructed EGUs. As reported by HGS here, EPA previously published CO2 standards for new EGUs in January 2014. This suite of proposals applies to the following types of EGUs: natural gas-fired stationary combustion turbines, fossil fuel-fired utility boilers, and integrated gasification combined cycle (IGCC) units, provided each has a heat input rate of at least 250 MMBtu/h, and supplies one-third or more of its potential electrical output and more than 219,000 megawatt hours net-electrical output to a utility distribution system, on a 3-year rolling average basis.

Proposed Emission Guidelines for Existing EGUs
The Emission Guidelines for existing EGUs consist of state-specific, rate-based “goals” and broad guidelines to help states develop plans to meet those goals. EPA’s proposal does not impose limits on individual EGUs, but rather establishes emission rates that must be achieved by the state as a whole, taking into account its various sources of power generation.

EPA’s proposal includes an “interim” goal that must be achieved from 2020-2029, and a “final” goal that must be achieved from 2030 onward. The interim goals range from 244 to 1,882 lb CO2/MWh among various states, with Florida’s proposed at 794 lb CO2/MWh. The final goals range from 215 to 1,783 lb CO2/MWh among various states, with Florida’s proposed at 740 lb CO2/MWh. In calculating these goals, EPA considered the unique characteristics of the state, and focused on four “building blocks”: (1) making fossil fuel-fired power plants more efficient, (2) using low-emitting power sources more, (3) using more zero- and low-emitting power sources, and (4) using electricity more efficiently.

Some of the measures EPA identified for states to rely on in achieving their goals include, but are not limited to:

  • Demand-side energy efficiency programs;
  • Renewable energy standards;
  • Efficiency improvements at plants;
  • Co-firing or switching to natural gas;
  • Transmission efficiency improvements;
  • Energy storage technology;
  • Retirements;
  • Expanding renewable or nuclear;
  • Market-based trading programs; and
  • Energy conservation programs.

Proposed Emission Standards for Modified and Reconstructed EGUs
EPA’s proposal for modified and reconstructed EGUs provides source-category specific emission standards.

Modified Utility Boilers and IGCC Units

For modified fossil fuel-fired utility boilers and IGCC units, EPA’s proposal provides two co-proposed alternative standards. Under the first alternative, the emission limit for each affected unit would be a 2% reduction from the unit’s best annual emission rate since 2002, but no more stringent than 1,900 lb CO2/MWh (net) if greater than 2,000 MMBtu/h, or 2,100 lb CO2/MWh (net) if less than or equal to 2,000 MMBtu/h. Under the second alternative, the emission limit depends on whether the unit was modified before or after becoming subject to an implementation plan for existing EGUs. For units modified before becoming subject to an existing unit implementation plan, the emission limit is the same as described under the first alternative above. For units modified after becoming subject to an existing unit implementation plan, the emission limit is determined by the implementing authority after taking into account energy efficiency improvement opportunities. These proposed standards are based on a combination of best operating practices and equipment upgrades, and are calculated on a rolling 12-operating-month period.

Reconstructed Utility Boilers and IGCC Units

For reconstructed fossil fuel-fired utility boilers and IGCC units, EPA’s proposal provides limits of 1,900 lb CO2/MWh (net) if greater than 2,000 MMBtu/h, and 2,100 lb CO2/MWh (net) if less than or equal to 2,000 MMBtu/h. These proposed emission limits are based on the use of the most efficient generating technology, and are calculated on a rolling 12-operating-month period.

Modified and Reconstructed Natural Gas-Fired Combustion Turbines

For both modified and reconstructed natural gas-fired combustion turbines, EPA’s proposal provides emission limits of 1,000 lb CO2/MWh (gross) if greater than 850 MMBtu/h, and 1,100 lb CO2/MWh (gross) if less than or equal to 850 MMBtu/h. These proposed emission limits are based on the use of natural gas combined cycle units, are the same as EPA’s proposed emission limits for new natural gas-fired combustion turbines, and are calculated on a rolling 12-operating-month period.

EPA will hold four public hearings on the proposals during the week of July 28, 2014, in the following cities: Denver, Colorado; Atlanta, Georgia; Washington, D.C.; and Pittsburgh, Pennsylvania. Comments on both proposals are due within 120 days of publication in the Federal Register, which is expected in the next few weeks.

 

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