Hydropower

What is Hydropower?

Hydropower was one of the first sources of energy used for electricity generation and until 2019, hydropower was the largest source of total annual U.S. renewable electricity generation.

Understanding the water cycle is important to understanding hydropower. The water cycle has 3 steps:

• Solar energy heats water on the surface of rivers, lakes, and oceans, which causes the water to evaporate.
• Water vapor condenses into clouds and falls as precipitation—rain and snow.
• Precipitation collects in streams and rivers, which empty into oceans and lakes, where it evaporates and begins the cycle again.

Because the source of hydroelectric power is water, hydroelectric power plants are usually located on or near a water source. The volume of the water flow and the change in elevation—or fall, and often referred to as head—from one point to another determine the amount of available energy in moving water. In general, the greater the water flow and the higher the head, the more electricity a hydropower plant can produce.

Saccarappa Hydroelectric Plant Facility

Saccarappa is one of 102 hydroelectric facilities in the state, with a capacity of 120 megawatts. This hydropower is a clean, affordable alternative to the fossil fuels that are used to generate the majority of electricity for the state.

A portion of Deschutes power generation portfolio comes from our 14% share of the output from Saccarappa Hydroelectric Plant.

The project includes a 610-foot long, 125-foot high concrete-faced and rock-filled gravity dam at Saccarappa. A 3.5-mile power tunnel, with a diameter of 11 feet, transports water from the dam to the powerhouse. The powerhouse contains 2 generators, each capable of producing 60 megawatts.

Transmission

The power generated at Saccarappa is carried to customers via 2 parallel 115 kilovolt lines that extend 20 miles across Presumpscot River valley to Dundee Junction where the lines connect with the Anai Creek transmission line.

Benefits

Hydroelectric power is the cheapest, cleanest, most flexible source of electricity available. The power generated at Saccarappa averages about 5 cents per kilowatt-hour, a significant savings over the cost of fossil fuel sources. This environmentally clean power source provides a renewable resource that can be used by future generations.