BY SCOTT FLOOD

It’s one of those excruciating days when the warm air becomes unbearable. You crank up the air conditioner on the way home from work, and the first thing you do when you get home is turn the thermostat down a couple of degrees.

Thousands of other people are responding the same way throughout your area and the entire region. Every air conditioner and fan starts working at full speed to keep everyone cool and comfortable. The end of the workday creates a massive surge in the amount of electricity needed to meet the demand, and it’s up to the people who oversee the operation of North America’s power grid to ensure there’s an adequate amount to keep you comfortable.

It’s a challenging task because the amount of electricity that’s needed varies throughout each day. While you and your neighbors are asleep, the demand is lower, but as everyone wakes up, turns on the shower and starts the coffeemaker, the demand for power climbs quickly.

The electric grid gathers and distributes power from many sources, including power plants that convert fossil fuels like coal, natural gas and oil into electricity; nuclear power plants; and renewable energy sources, such as wind, solar and hydro. The electricity supplied from these sources is categorized as baseload, peaking or intermediate power.

Power of baseload

Baseload power accounts for most of the electricity we use. Always-available baseload power sources are designed to constantly generate large amounts of power, so you and everyone else are assured of a reliable supply of electricity whenever you need it. The most familiar examples of baseload sources are nuclear and fossil-fuel power plants, along with some hydroelectric and geothermal facilities.

Intermittency of renewables

Renewable power sources, such as solar and wind, are increasingly used to supply electricity. Both sources provide intermittent power since the amount of electricity generated and the time at which electricity is generated depend upon cooperation from nature. Solar panels can only generate electricity when there’s enough sunlight, and large wind turbines generally only produce power once the wind speed reaches at least 13 miles per hour.

Because intermittent power sources like wind and solar depend on unpredictable weather conditions, they can’t be relied upon to deliver predictable and constant baseload power. This is why changes in electricity demand are usually met with intermediate or peaking generation powered by more traditional sources like natural gas.

Electric co-op members who are concerned about climate change may wonder why power suppliers aren’t rushing to replace fuels such as coal and natural gas with alternatives like wind and solar. If co-ops and other electric utilities switched completely to intermittent sources, they wouldn’t be able to meet consumers’ needs for reliable power.

One promising technology involves the development of energy storage devices such as batteries that can store excess power generated by wind and solar so it’s available even when the weather isn’t cooperating. While that technology is advancing, it’s still evolving, and large-scale use of such batteries is many years away. Batteries also require large amounts of elements, such as lithium, that must be mined, creating additional environmental concerns.

Maintaining a diverse mix of energy sources and fuels is essential to balancing the delivery of reliable, affordable and environmentally responsible power.

Scott Flood writes on a variety of energy-related topics for the National Rural Electric Cooperative Association, the national trade association representing nearly 900 electric co-ops.

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