Behind the Grid: Hydropower


(Published, 04/01/2020, Ruralite)

hydroelectric damHydroelectric power is among the earliest and simplest ways to generate electricity. It is a renewable resource taking advantage of the natural water cycle. The flow of water through a dam generates electricity year-round. There are three main types of hydroelectric facilities including: impoundment, diversion, and pumped storage hydropower.

Water flows from a higher to a lower elevation. This constant running flow of water spins turbines and generators to convert this motion into electricity. The water then exits the turbine and is returned below the dam.

Hydropower works well in some areas and not in others. It is advantageous if the body of water (river) is either large or swift. The northwest has high capacity for hydropower as many powerful rivers in the Columbia drainage basin begin with high elevations and then flow swiftly into the Pacific ocean.

There are over 300 hydro projects in the Northwest including: four on the Lower Snake, fourteen on the Columbia (3 in Canada, 11 in the US), one on the Clearwater.

Hydroelectric power is cost-stable. The rivers that flow through dams are a sustainable resource and are not affected by market volatility.

The power generated at a dam is “firm.” Meaning, that it can be called upon when needed and left off when not needed. This is crucial to utilities and consumers. It is also crucial to non-firm sources like wind and solar which need firm sources to back them up when the wind isn’t blowing or when sunlight is not present. Water can be stored behind a dam to be released when needed. In this way, reservoirs act as giant batteries; the weight of the water is potential energy.

There are also many ancillary benefits to hydroelectric dams including flood control, irrigation, transportation of goods, and recreation.

The hydroelectric process produces zero greenhouse gas or other emissions into the atmosphere. Dams alter the natural flow of rivers so there is a significant environmental impact to the environment. Although many dams are built with fish passage, many are not. Slow-moving water in reservoirs can get warmer than swift-moving water. This also has a significant impact on the environment.

  • Industrialization of the northwest has many environmental impacts. Hydropower sales provide financial support to help mitigate those impacts - regardless of whether the impact is related to dams.
  • The Federal government recently released a Draft Environmental Impact Statement (DEIS), which provides a comprehensive analysis of the Northwest’s federally-operated hydro system. Agencies were tasked with specifically examining the lower Snake River dams, their impact on salmon, and what purpose they serve for our region. Visit the Northwest River Partners website for more information.