A power plant generates electricity. Most plants use a heat source to make steam, which spins a turbine connected to a generator. The heat can come from burning coal, gas, or oil, from nuclear fission, from concentrated sunlight, or from geothermal wells. Hydro and wind plants skip the steam step and spin turbines directly.

Plants vary in size and role. Baseload plants run continuously and produce cheap power. Peaking plants fire up only when demand spikes. Combined-cycle gas plants capture waste heat to boost efficiency above 60 percent. Solar and wind farms are often called plants too, though they generate without combustion.

Location matters. Plants need cooling water, fuel delivery, or transmission access. Coal and nuclear plants sit near rivers or lakes. Gas plants can be built closer to cities. Solar farms need open land and sun. Wind farms need steady breezes. Each choice involves trade-offs in cost, environment, and politics.

Common types

• Coal-fired
• Natural gas combined cycle
• Nuclear
• Hydroelectric
• Solar and wind farms