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.