Hydro Power Still Works

Energy from flowing water has been used for more than 2,000 years; ancient Greeks thought up the first waterwheels for grinding wheat into flour. In the 1880s, converting a rush of water into electricity became a reality in the United States. Within a decade, 200 U.S. plants were using water power for generation.

Today, hydropower provides just under 7 percent of the nation’s electricity. In Kentucky, it’s about 3 percent, because coal produces nearly all of Kentucky’s electricity.

Hydropower converts the energy in moving water to mechanical energy. A waterwheel attached to a mill becomes a basic means to that end. If that waterwheel (or its modern equivalent, a turbine) is attached to a generator, electricity results.

Hydro turbines can produce electricity in a number of ways:

Impoundment
By plugging a river and amassing water in a reservoir, its flow can be controlled and electricity generated as needed.

Diversion
Water is channeled from a river, typically near natural falls, down to generators at the falls’ base. This kind of generation brought electricity to Buffalo, New York, from Niagara Falls in the late 1800s.

Pumped storage
This uses off-peak electricity to make electricity for times of high consumption. Two reservoirs are filled, one uphill from the other, by an electric pump/generator in between. At night, when demand is low and electricity is less expensive, water from the lower reservoir gets pumped uphill. During the day, when demand for power increases, water is released to make electricity.