Introduction
Coal has long been the major fossil fuel used to produce electricity. However, the Environmental Protection Agency (EPA) lists coal-fired electric power plants as one of the largest sources of air pollution in the United States, with greenhouse gas1 (GHG) emissions from burning fossil fuels believed to be the largest contributor to global climate change.
Regulations under development at EPA would impose new requirements on power plants to control GHG emissions. First, in September 2013 EPA proposed standards for the control of carbon dioxide (CO2) emissions from new electric generating units burning fossil fuels. EPA has suggested that utilization of carbon capture and storage (CCS) is a viable means for new coal- fired power plants to comply with the proposed standards.2 But higher efficiency components and processes are unlikely to be sufficient to meet the proposed new plant standards. As requirements for new sources (i.e., new power plants), EPA’s proposed standards do not directly apply to existing power plants currently producing electricity. EPA’s proposals for control of GHG emissions from existing power plants are expected by June 2014,3 with many options for reducing GHGs under consideration. EPA may target emissions on a state or plant-by-plant basis, with companies likely given choices for compliance, and increasing coal-fired power plant (CFPP) efficiency may be one of those choices.
Improving the efficiency of existing coal plants could potentially result in significant reductions
of CO2 emissions per unit of electricity produced. However, certain modifications to power plants to increase power output can potentially increase pollutant emissions, thus triggering new source review4 (NSR) requirements. Therefore, any modifications made must be shown to reduce pollutants if NSR is to be avoided. Expenditures to increase efficiency would likely be evaluated on a cost vs. benefits approach, with modifications to improve efficiency varying according tomany factors, including the type of fuel burned, and the age and the physical condition of the power plant.
Carbon capture and sequestration (CCS) will not be a focus of improvements discussed in this report, as there are no CCS technologies considered as commercially available for full-scale application to the broad majority of existing coal-fired power plants,5 and EPA has stated that it does not expect to require CCS at existing plants.
This report focuses on efficiency improvements to power plants, and discusses retrofits, technologies, and other modifications to facility operations which offer the potential to improve power plant efficiency and reduce CO2 emissions. Some in Congress have expressed concerns about the potential impacts on electricity reliability and fuel diversity from retirements of coal plants due to pending and new environmental regulations. Increasing efficiency of coal plants may help to address these concerns by reducing emissions without reducing output. Additionally, Congress may want to consider whether such efficiency improvements could be accelerated if
these were implemented in a program focused on increasing the efficiency of the coal-fired power plant sector.