Improving the efficiency of existing coal plants could potentially result in large reductions of CO2 emissions per unit of electricity produced. Since GHG emissions from electricity generation are essentially composed of CO2 emissions, improvements in efficiency are a direct means of
reducing GHG emissions.
The performance of a power plant can be expressed by a number of measures, including heat rate (i.e., the efficiency of conversion from fuel energy input to electrical energy output), and thermal efficiency. In its simplest form, a plant’s heat rate (for a particular period) can be defined as follows: