What is Hydropower & Where Does it Come From?

What is Hydropower? (infographic) - High Tide Technologies


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Hydropower Explained

Hydropower is a renewable energy source that converts flowing water into electricity. Turbine rotors are connected to generators and when water flows through them, causing them to spin— the generators create electricity. There are three main sources of hydropower, which can often overlap:

1. Impoundment Facilities: This is the most common source. It uses a dam and relies on the gravitational pull of water to produce energy.


2. Pumped Storage Facilities:  This source is similar to impoundment facilities, but contains a second reservoir below the dam. Water can be pumped up from the lower reservoir to the upper reservoir to store energy.


Run-of-River Facilities: This method relies on natural water flow rates, sometimes without the use of a dam or reservoir.


Largest Hydropower Facilities in the US

Columbia River Power Stations: 5 out of 11 largest hydroelectric power plants

  • Grand Coulee Dam (Grand Coulee, Washington)
  • Chief Joseph Dam (Bridgeport, Washington)
  • John Day Dam (Goldendale, Washington)
  • The Dalles Dam (The Dalles, Oregon)
  • Rocky Reach Dam (Chelan & Douglas Counties, Washington)

Hoover Dam: 

  • Black Canyon, Colorado River (Nevada & Arizona)
  • Generates enough power to serve 1.3 million American homes


  • Pumped storage plant that draws from Lake Michigan (Ludington, Michigan)

Raccoon Mountain

  • Pumped storage plant that draws from Nickajack Lake (Chattanooga, Tennessee)

Glen Canyon Dam

  • Draws from the Colorado River (Nevada & Arizona)

Bath County

  • Pumped storage plant located in Bath County, Virginia


Hydropower Usage in the US

In 2017, the total installed capacity of hydropower was nearly 103,000 MW – that’s enough to power up to 103 million American homes.

  • Today, the US hydropower fleet contains 2,198 active power plants across 48 states
  • Half of U.S. hydropower capacity is located in three states: Washington, California, and Oregon
  • Only two states, Delaware and Mississippi, have NO utility-scale hydropower generating facilities
  • Four states—Washington, Idaho, Oregon, and Vermont—depend on hydropower facilities for at least half of their in-state utility-scale generating capacity


Hydroelectric Power is the Largest Source of Renewable Electricity

  • Hydroelectric power is currently the largest producer of renewable electricity in the country, generating around 6.4% of the nation’s total electricity in 2016 as well as 43.94% of the total renewable electricity generation
  • In 2017, the total installed capacity of hydropower was nearly 103,000 MW – that’s enough to power up to 103 million American homes

The Pros & Cons of Hydropower

Hydroelectric Power Pros

  • Cost competitive and a good long-term solution, despite a heavy upfront investment
  • Reliable in comparison to other renewable energy sources such as wind and solar
  • Compatible – can be used as based-load power
  • Flood control from dammed reservoirs


Hydroelectric Power Cons

  • Causes environmental change in local landscapes and ecosystems
  • Risk of dam failures or drought
  • Not entirely free of greenhouse gas emissions, due to the large amount of concrete used in building


How Can Hydropower Shape the Future?

The U.S. Department of Energy released a road map that aims to increase installed capacity by nearly 50 GW by 2050, a 49% increase from today’s installed capacity.

This report claims that investing in this increase of installed capacity can reduce greenhouse gas emissions by 5,600,000,000 metric tons by 2050. This would reduce greenhouse gas emissions by nearly 3% each year.

Reducing these emissions can help avoid the following:

  • $209 billion in global damages
  • Nearly 5 million cases of acute respiratory symptoms
  • Nearly 750,000 cases of childhood asthma

This investment would also establish 195,000 hydropower-related gross jobs spread across the nation in 2050