Storing Electricity the Old-Fashioned Way with New Technology – Pumped Storage Hydropower

Author:  Jean Stammeyer, Account Manager, Kinect Energy

An abundance of technology and research has been dedicated to developing ways to store electricity such as high tech batteries, mechanical flywheels and compressed air energy storage.

However, with the increased supply in wind and solar generation many utilities have turned to a much older, time-tested technology – pumped storage hydropower.  Hydropower has been around since the late 1800s and the origins of the technology reach back thousands of years.  The ancient cultures of Greece and China used water-powered mills for necessary activities such as grinding wheat.  In 1849, an engineer named James Francis developed the Francis Turbine.  This is the same type of turbine most widely used today.

Hydropower Milestones

1849: Invention of the Francis turbine.

1882: The world’s first hydropower plant begins operations in Appleton, Wisconsin, on the Fox River.

1887: The first hydroelectric plant opens in the West, in San Bernadino, California.

1907: Hydropower accounts for 15 percent of U.S. electrical generation.

1920: Hydropower accounts for 25 percent of U.S. electrical generation.

1931: Construction begins on the Hoover Dam, ultimately employing a total of more than 20,000 workers during the Great Depression.


1937: The Hoover Dam begins to generate power on the Colorado River.

1941-1945: Bureau of Reclamation dams ramped up power output to support America’s efforts in World War II, producing enough electricity to make 69,000 airplanes and 5,000 ships and tanks during a five year period.

1980: Conventional hydropower capacity is nearly triple compared with 1920 level.

Today: A vast expansion of hydropower’s potential is possible through new technologies for conventional, pumped storage and marine and hydrokinetic projects, modernizing existing hydropower facilities and adding generation to existing non-powered dams

Source; DOE

Pumped storage provides grid reliability on a large scale and is an affordable means of storing and deploying electricity.  Pumped storage projects store and generate electricity by moving water between two reservoirs at different elevations.  On nights and weekends when the demand for electricity is low, the surplus energy is used to pump the water to the upper reservoir.  During the work week and on hot summer days when demand for electricity is high, the stored water is released through the turbines in the same manner as a conventional hydro station, flowing downhill from the upper reservoir into the lower reservoir, generating electricity.  The turbine also acts as a pump, moving the water back uphill.


The U. S. has more than 20GW of pumped storage capacity today.  There are facilities in every region of the country with proposals to develop an additional 31 GW of capacity.  The majority of the projects are currently planned in the west region in support of the increasing amount of variable generation coming on line. Clean and renewable energy sources are constantly evolving creating the need for large scale storage.  New technologies are being developed to store and squeeze energy out of the approximately 80,000 U. S. dams that currently do not produce power.

As of 2015, pumped storage hydropower has provided 97% of the total utility-scale electricity storage in the United States.  Pumped storage hydropower has proven to be a reliable and commercially available, large scale, storage resource.


The majority of pumped storage hydropower facilities have been developed by utilities, both public and investor-owned.  Independent Power Producers have shown an increased interest in new pumped storage projects and have filed a number of applications for preliminary permits with FERC.  Approximately 80% of the active permits for pumped storage hydropower projects are held by IPPs.
These preliminary permits represent more than 15,000 MW of capacity.

Estimated 62% Growth – Pumped Storage Hydropower by 2050 (51GW)


Some of the challenges developers face for new pumped storage hydropower projects have to do with environmental issues.  Previously, most operating storage projects required the construction of at least one dam along main stream rivers altering the ecology of the river system and affecting the fish and other wildlife.   A relatively new approach is to locate the reservoirs in areas that are physically separate from existing river systems. These projects are termed “closed –looped” pumped storage and have minimal to no impact to the existing river system.  Once the reservoirs are filled, the additional water requirement is minimal operational make-up water to offset evaporation and seepage losses.

Another signification challenge is the long timeline for development of a new project.  Under the current FERC licensing process, obtaining a new project license to construct takes 3 to 5 years or longer before the developer can begin construction.  Currently the licensing process is the same for both open- looped and closed- looped projects.  At this time there is not an alternative licensing process for low-impact or close-looped projects to shorten the time frame.  In addition to the licensing process, a large scale project will take at a minimum 3 to 5 years or longer to construct depending on the environmental requirements.


Leave a Reply

Your email address will not be published. Required fields are marked *