Hydropower and what it entails

Coulee Dam in Washington. Source: United States Geologic Survey (USGS)

Hydropower currently constitutes seven percent of America’s energy, and 66% of America’s renewable energy. These numbers show that hydropower has definitely earned its position as an important player in the field of energy production in the  United States. In fact, the United States comes in at second place in producing the most installed capacity of hydropower at approximately 100 GW. According to the National Hydropower Association, hydropower provides energy to over 30 million homes in America.

The benefits

Hydropower is a source of energy that does not produce carbon dioxide emissions and is usually available when other sources of energy are not. Rainfall and snowmelt accumulates at higher elevations and creates a significant amount of energy that can be harnessed  as it flows to lower elevations.  This form of power also has the lowest cost of all energy forms, and its equipment has fairly long lifespans (approximately 50 years).

Probable development

The possible expansion of hydropower deals primarily with adding hydroelectric facilities and infrastructure to pre-existing dams. Only 3% of America’s 80,000 damns currently generate electricity – that’s a lot of untapped power! Small installations in irrigation canals and streams are currently where hydroelectric action is expanding, often having low cost and low impact. The Federal Energy Regulation Committee (FERC), which is responsible for overseeing the safety of non-federal dams, issued 15 permits for small hydro in 2007, and over 50 permits in 2009! Other major sources of hydropower that are yet to be further tapped are wave, ocean current, and tidal in-stream.

Visualization of how hydroelectric power is produced. Source: Texas Comptroller

Challenges for hydropower expansion

Initiating hydroelectric development is no easy task considering it involves going through an approval process of the Federal Energy Regulatory Commission, federal and state, resource agencies, local governments, tribes, NGOs, and the public. Although in the long run hydropower is cheaper than other energy sources, up front costs are high and make the expansion of hydropower challenging. Incentives, primarily involving tax credit and Clean Renewable Energy Bonds (CERBs), offer a fair amount of support for hydro development.

Negative impacts

The primary negative impact of hydropower is that fish populations typically decline once a dam has been established. Fish are interrupted from being able to travel up stream and continue their reproduction process, sometimes impacting communities that rely on fish as a source of income. Hydroelectric plants have attempted to lessen the negative impact by building fish passages and fish ladders which have had some success, but migratory patterns are still disrupted.

Remnants of St. Francis Dam of Southern California. Source: Owens Valley History

Dams also impact river activity as a whole, often altering temperature, flow patterns, sediment transport, etc. These types of alterations can have considerable effect on the life and structure of the river, as well as native plants and animals that are located in or near the river.

Not to mention dam failure can pose serious threat to humans, wildlife, and the environment in the region as a whole.

Extra information:

  • 1882 – The first hyroelectric plant opened in Wisconsin
  • 1920 – Hydroelectric accounts for 25% of power in US
  • 1937 – Hoover Dam generates power
  • The largest hydroelectric plant is located at Coulee Dam on the Columbia River in northern Washington
  • States receiving the most hydropower are Idaho, Washington and Oregon

Cited sources:

National Hydropower Association (NHA)

“Hydropower: Going with the Flow”


NHA – pumped storage

Written by Lauren, Geology major and social activist based in Southern California

Official Enlighten Together project Click to enlarge.

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