Power Plants
Battelle has provided a well-written report that discusses power plant coal utilization in great detail. It gives
a thermal efficiency of 80-83% for steam generation plants and 37-38% thermal efficiency for power generating plants at base load (about 70%). A base load plant designed for about 400 MW and up will run at steam pressures of 2,400 or 3.600psi and 1,000”F with reheat to 1.000”F and regenerative heating of feedwater by steam extracted from the turbine. A thermal efficiency of 40% can be had from such a plant at full load and 38% at high annual load factor. The 3,600psi case is supercritical and is called a once-through boiler, because it has no steam drum. Plants designed folr about 100-350MW run around 1,800 psi and 1,000”F with reheat to 1,000”F. Below 100 MW a typical condition would be about 1,350psi and 950°F with no reheat. Below 60% load factor, efficiency falls off rapidly. The average efficiency for all steam power plants on an annual basis is about 33%.
