Plants, Poles and Plugs

Electric Companies Meet Peak Consumer Demand By Keeping Additional Generating Capacity Available.
Electricity must be produced when customers need it. Energy can neither be created nor destroyed — it can only be transformed (converted) from one form to another. Because electricity cannot be stored easily or economically, electric companies and other electricity suppliers must have enough generation facilities available to meet the maximum demand on their systems, whenever that occurs.

The electric load that electric companies and other electricity providers must supply is the sum of all customers’ demands. Because customer needs vary constantly, demand varies constantly, too. Heaviest demand usually occurs during the day from all sectors—industrial, commercial, residential, and transportation—and lowest demand during the night. Demand also varies with the seasons and with changes in the weather.

To ensure that there is enough electricity available to meet customer demand, some plants work around the clock, allowing electric companies and other power providers to generate a steady supply of electricity equal to the demand of their customers. Typically, companies use coal-based, hydro, or nuclear plants to provide this continuous service because they are cheaper to run for prolonged periods.

Pumped storage hydro, natural gas, or oil-based units are usually the units of choice for providing service for the hours of the day when demand hits its highest levels or peak. These peaker units may be started and stopped quickly, unlike coal- and nuclear-based plants.