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America’s first carbon-free renewable energy resource – hydropower

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Kent Knutson's picture
Energy Market Specialist, Hitachi Energy USA Inc.

Kent Knutson is a market specialist focusing on energy industry intelligence for Hitachi Energy.  He has more than 30 years of experience designing and developing intelligence products for some...

  • Member since 2018
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  • Feb 12, 2021

Often forgotten in the discussion of carbon-free power resources, America’s hydroelectric power plants have been consistent power producers for over fifty years. Since 1970, the country’s hydroelectric dams have produced more than 14.1 trillion MWh with an average annual output of 281 million MWh, which is an astounding statistic considering there has been little hydropower development during the past 30 years.  In 2019, hydro contributed 288 million MWh to America’s fuel mix – just behind wind’s record 295 million MWh contribution.     

With the right weather conditions, hydro can be a large carbon-free power contributor.  In 1997, driven by widespread high levels of winter snowfall and precipitation, hydro produced a record 356.4 million MWh which amounted to roughly 10.2% of total electricity generation across the country.  To put that in perspective, consider that in 2020, wind generated about 332 million MWh – about 8.3% of the total U.S. power supply.  Seventy years ago, in 1950, hydro accounted for around 30% of the total U.S. power supply, and a decade later, in 1960, water still accounted for about 20% of the overall power supply.

U.S. electricity production from hydro, wind, and solar resources, TWh

From data compiled by the Hitachi ABB Power Grids’ Velocity Suite research team, today there are over 2,000 (100 GW) operating hydroelectric plants in the U.S. made up of 79.1 GW of conventional hydroelectric capacity and 21.7 GW of hydro pumped storage (HPS) capacity.  The average age of the conventional fleet is nearly 65 years, while the average age of the HPS fleet is about 43 years.  

Though the majority of hydro capacity in the United States is owned and operated at federal agencies (49%), and public entities including utility districts, irrigation districts, states, and rural cooperatives (24%), there are a substantial number of investor-owned utilities (IOUs), independent power producers, and industrial companies (25%) owning hydropower capacity as well.

Hydropower’s long and storied history

Generating electricity by water was truly the first carbon-free power resource in America.  The world’s first hydroelectric project was used to power a single lamp at the Craigside Country House in Northumberland, England in 1878.  Though there were a handful of hydroelectric facilities introduced in the U.S. and Canada after Craigside, they served supply mills and a few small electric lighting installations.  The first commercial hydroelectric power plant opened in Appleton, Wisconsin, in September 1882.  The Vulcan Street plant, built along the Fox River, is now a National Historic Mechanical Engineering Landmark. 

Vulcan Street Hydropower Plant replica, Appleton, WI

Image: Courtesy of the Wisconsin Historical Society and the City of Appleton

H.J. Rogers, the President of the Appleton Paper and Pulp Company and the Appleton Gas Light Company, conceived the plant.  The development and construction of Vulcan occurred at about the same time Thomas Edison was building the first steam-driven electric power plant (12.4 MW) on Pearl Street in New York City.  The original dynamo (machine converting mechanical energy into direct-current electrical energy) constructed at Vulcan was 12.5 kW with the power used to illuminate sixteen candle lamps.  The success of Vulcan quickly led to the development of hydropower plants across the U.S.  By 1886, there were around 50 operating hydro plants, and by 1888, there were 200 plants in operation across the country.  Ten hydropower plants built in the 1800s are still operating today.  By 1907, more than 15% of all electricity produced in the U.S. was sourced from water. 

The first commercial alternating-current (AC) plant was built in Redlands, California in 1893, while the first hydro pumped storage facility was introduced in Connecticut in 1929.  

In the 1930s and 1940s several major hydropower milestones were achieved, including the completion of the iconic Hoover dam along the Colorado River in 1936, and the completion of the country’s largest power generating dam in 1942, Grand Coulee on the Colombia River in Washington.

The future is looking brighter

Most of the hydropower projects in development today center on life extension of the rapidly aging existing fleet, with additional interest in integrating power generating technology into the nation’s large number of non-power dams (NPDs), canals, and conduits built for flood control, water storage, irrigation, and other non-power producing purposes.

Additionally, driven by the rapid development of variable wind and solar projects, HPS is getting a strong look by grid managers as a potential grid balancing and long-duration storage resource.  Today HPS represents about 93% of all grid storage capacity in the country.  The 43 operating HPS projects account for about 99% of all-electric energy production among storage solutions. 

According to the Department of Energy’s (DOE), January 2021, U.S. Hydropower Market Report, there are about 50 GW of HPS projects currently under construction globally, most in China and Southeast Asia, while in the U.S., there are over 50 GW in various stages of development but currently, no significant projects have broken ground. 

Map of pumped hydro storage (PHS) project development pipeline by region and development stage as of December 31, 2019, GW

Source: The U.S. Department of Energy (DOE) U.S. Hydropower Market Report, January 2021, from data compiled by Oak Ridge National Laboratory from IIR and FERC

Despite the small number of hydro installations in recent years, with only 1.7 GW of capacity net increases reported between 2010 and 2019, there were 1.5 GW in development at the end of 2019.  More than half of those projects have federal licenses in-hand but are yet to start construction. 

Hydropower capacity changes by region and by type, MW values, and project count, 2010-2019

Source: The U.S. Department of Energy (DOE) U.S. Hydropower Market Report, January 2021, from EIA Form 860 (2010-18) and Form 860 Early Release (2019) Existing Hydropower Assets dataset, FERC eLibrary

There have been no large-scale hydro plants built in twenty-five years in the U.S.  The last projects that exceeded 250 MW were the Northern California Power Agency’s (NCPA) Collierville Powerhouse (253 MW) in 1990, and the expansion (478.8 MW) of Seattle City Light’s Boundary project in 1985 and 1986.

Hydroelectric projects in the news

About six years ago, Sioux Falls, South Dakota based, Missouri River Energy Services, with financing from Western Minnesota Municipal Power Agency (WMMPA), started construction on an ambitious hydro project designed to generate electricity from one of the nation’s non-powered dams (NPDs) near Pella, Iowa.  The Red Rock Hydroelectric Project (36 MW) dedicated in August 2020, is the second-largest hydroelectric dam in the state of Iowa.  The construction effort took place on the existing fifty-year-old U.S, Corp of Engineers (USCE) owned and operated Lake Red Rock Dam on the Des Moines River.   

According to statistics compiled by the National Hydropower Association, there are as many as 80,000 NPDs across America, representing a significant opportunity to develop dispatchable carbon-free power – the perfect complement to variable resources like wind and solar.  Additionally, the U.S. Department of Energy (DOE) estimates, that with only 3% development of NPDs and conduit type facilities, up to 12 GW of new electricity-producing capacity could be added to the nation’s grid rather quickly. 

The Red Rock power facility represents a successful private/public development project and serves as an indicator of the opportunity for other projects, especially with the current strong government support for carbon-free power across the U.S.        

In early January 2021, the non-profit Kauai Island Utility Cooperative (KIUC) signed a contract with energy-storage leader AES Corporation to build a solar-powered hydro pumped storage (HPS) system to provide power during nighttime hours across the island.  The KIUC contract involves two closed-loop HPS systems (4 MW and 20 MW) to be fully powered by a two-part solar framework involving 56 MW of direct current (DC) and 35 MW of alternating current (AC) – at full output, the 20 MW HPS would provide about 25% of the island’s current peak demand.  The system includes a small battery storage system next to the solar farm to provide backup power during times of cloud cover to keep the water pumping to the upper reservoirs.  Because the system is closed-loop, with only carbon-free solar power providing the energy to pump water, it qualifies for the federal investment tax credit (ITC).

In late January, Allegheny County in Pennsylvania announced they had entered into a 35-year power purchase agreement (PPA) with Rye Development for power generated at a 17.8 MW facility on the Ohio River.  The project is located at the existing U.S. Corps of Engineers operated Emsworth Main Channel Dam.  If all goes to plan, the project will begin construction later this year and is expected online by mid-2023.    

Projects like the NPD expansion at Red Rock and Allegheny County, and the Kauai Island hydro pumped storage plan, are indicative of America’s hydroelectric development potential as a carbon-free contributor in the years to come.

Supporting policy

The most significant problem facing hydro plant development is the long licensing process which, according to the DOE report, can take up to 10 years to complete. 

In support of hydro development, the American Water Infrastructure Act (AWIA) was enacted in 2018.  The policy directed the Federal Energy Regulatory Commission (FERC) to expedite the licensing process to no more than two-years from application filing to a final decision.  The policy supports the development of non-power dams and conduit structures, and qualifying hydro pumped storage facilities.

The 1978 Public Utilities Regulatory Policies Act (PURPA) supports renewable energy qualifying facilities (QFs), including small scale hydroelectric projects, by providing the right to interconnect to the grid and by guaranteeing a price for the electricity produced.  The power price is set at the ‘avoided cost’ of the buying company or organized market to contract or build an equivalent facility.  When the policy was established, more than 40 years ago, it resulted in a significant buildout of private hydro facilities across the country.

Global hydro market on the move

Global hydropower capacity increased by roughly 63 GW between 2017 and 2019 alone, and the pipeline is immense, with over 400 GW across more than 4,500 potential projects worldwide.  At the end of 2019, there were 53 GW of pumped hydro storage projects alone under construction around the globe. 

Map of hydropower project development pipeline by region and development stage as of December 31, 2019, GW

Source: The U.S. Department of Energy (DOE) U.S. Hydropower Market Report, January 2021, from data compiled by Oak Ridge National Laboratory from IIR and FERC

Hydropower provides tremendous benefits including black start performance, 1-hour ramps, frequency regulation, reserves, and can stand the test of time with life cycles potentially reaching 100 years.  With policy incentives and the need for carbon-free dispatchable power in the fuel mix, hydropower projects will increasingly look more attractive.

Hydropower in the United States will continue to play a significant and growing role in the transition to a cleaner power grid.  The long-duration storage of pumped hydro systems and the potential to convert existing non-power dams and conduits into electricity-producing assets makes hydropower in America a good bet. 

Matt Chester's picture
Matt Chester on Feb 12, 2021

Love the history lesson-- thanks Kent!

When people tend to not get excited about hydro, I imagine it's because it's still the same it's looked for quite some time and there's a ceiling naturally to where/how much it can grow. But are there any technologies (digital, AI, etc.) that might come along that help us extract more power more efficiently out of hydro resources? Is hydropower at all a part of the digital revolution / transformation? 

Dr. Amal Khashab's picture
Dr. Amal Khashab on Feb 12, 2021

Hi Matt

(1)There is a great potential of Non-Dam Hydro everywhere in the globe. They are much easier than other renewable sources. They can cover a wide spectrum from tens of KW to 5 MW as mini and small hydro projects , which make them very suitable to microgrid applications. 

(2) In Egypt , Electricity and Irrigation Authorities  studied carefully how to make use of the Nile River flow through branches and canals , and found that sum of about 200 MW capacities could be installed.

(3) Concerning digital and AI technologies , they are applied in monitoring and controlling applications of these new hydro plants.

Matt Chester's picture
Matt Chester on Feb 12, 2021

200 MW of new hydro isn't too shabby-- love to hear it! And thanks for the intel on the digital tech. 

Jim Stack's picture
Jim Stack on Feb 12, 2021

Kent, you are Clark Kent superman. Hydro is one of my favorite power systems. I live in a desert called  Phoenix Arizona area. We are in a 20 year Mega drought yet we have 7 large dams that produce 8% of our power 24/ 7 operated by SRP , a Government non profit.  I have Solar that adds energy during thr peak hours of the day. 

   These power plants are over 50 years old. I encourage the operators to upgrade them so they could make double or triple the power. They also provide flood control here in the desert. 

   This is a great resource. They even use some for pumped storage. The possibilities are limitless but many seem to forget about them.   

   Thanks for telling about this great clean low cost energy. I hope it becomes the top area for upgrades and innovation. It has been over looked for too long. 

Mark Silverstone's picture
Mark Silverstone on Feb 12, 2021

I concur that hydropower is a vital source of emissions free power and it is likely to increase in importance. But I find it disconcerting and, not a little disingenuous on the part of the author of the post, that no mention is made of the possible down sides of hydropower with respect to potential environmental and social damage from such projects. If the result of the American Water Infrastructure Act (AWIA) is

“to expedite the licensing process to no more than two-years from application filing to a final decision."

then it becomes highly unlikely that possible negative environmental and social impacts can be properly discovered, investigated and mitigated sufficiently.  That is not progress.  On the other hand, if the work necessary to address environmental and social concerns are put in ahead of application, it may be possible to meet that two year time horizon if the competent regulatory bodies exist, and if they  have workable processes in place to ensure compliance with an effective regulatory process. However, after the last four years, I doubt that such a system exists in the US, much less policies that are tried and tested or administered by competent authorities.

I suggest that the long lead times for new hydropower plants are partly the result of the complex, but valid environmental and social issues that need to be considered.   I further suggest that the process of reaching consensus on the environmental and social effects of hydro projects is still more complex. The issues are often difficult, if even possible, to resolve  in a short time.  So, the lengthy regulatory process is often frustrating, but nonetheless necessary.  The risks of improper environmental and social impacts are many.  One is the possible large scale emissions of greenhouse gases during construction as described here.

«...estimates for life-cycle global warming emissions from hydroelectric plants built in tropical areas or temperate peatlands are much higher. After the area is flooded, the vegetation and soil in these areas decomposes and releases both carbon dioxide and methane. The exact amount of emissions depends greatly on site-specific characteristics. However, current estimates suggest that life-cycle emissions can be over 0.5 pounds of carbon dioxide equivalent per kilowatt-hour.» 

«To put this into context, estimates of life-cycle global warming emissions for natural gas generated electricity are between 0.6 and 2 pounds of carbon dioxide equivalent per kilowatt-hour and estimates for coal-generated electricity are 1.4 and 3.6 pounds of carbon dioxide equivalent per kilowatt-hour.


«A dam and reservoir can also change natural water temperatures, water chemistry, river flow characteristics, and silt loads. All of these changes can affect the ecology and the physical characteristics of the river. These changes may have negative effects on native plants and on animals in and around the river. Reservoirs may cover important natural areas, agricultural land, or archeological sites. A reservoir and the operation of the dam may also result in the relocation of people. The physical impacts of a dam and reservoir, the operation of the dam, and the use of the water can change the environment over a much larger area than the area a reservoir covers.»

There are some peer reviewed,comparative experimental data on impacts of hydroprojects:

«…the objective of our study was to analyze the geomorphologic dynamics of the coast immediately adjacent to the estuaries of two dammed rivers and compare it with that of the region’s two nondammed rivers, describing the differences between the two systems.»

«The economic consequences of this dam-induced coastal erosion include loss of habitat for fisheries, loss of coastal protection, release of carbon sequestered in coastal sediments, loss of biodiversity, and the decline of estuarine livelihoods. We estimate that the cost of the environmental damages a dam can cause in the lower part of basin almost doubles the purported benefits of emission reductions from hydroelectric generation.»

However, some hydro projects have less environmental and social impact than others as reported here:

“…small Hydropower, i.e. plants with a capacity of less than 10 MW: they are often run-of-river hydro plants and, thanks to the absence of a storage basin, have a minor impact on the hydrological regime of the river, one of the most important sources of environmental impact. Secondly, the application of a careful and modern design based on the application of mitigation and compensation measures that can ameliorate integration of Small Hydro Plants (SHP) in the environment.»

That lesson has been learned in some places, but not, apparently, in others.

The European Investment Bank has published Environmental, Climate and Social Guidelines on Hydropower Development

I might be able to believe that the “two-years from application filing to a final decision» threshold may be approachable if there are policies and directives in place such as exist in Europe:

•SEA Directive 2001/42/EC.

•EIA Directive 2011/92/EU as amended by 2014/52/EU.

•Water Framework Directive 2000/60/EC (see Box 3).

•Habitats Directive 92/43/EC. •Birds Directive 2009/147/EC.

it is possible to develop plans that assessments such as these that can be included for consideration and compliance appraisal prior to official submittal of applications.

•Assessment and Management of Environmental and Social Impacts and Risks

•Pollution Prevention and Abatement

•Biodiversity and Ecosystems

•Climate Change related Standards

•Cultural Heritage

•Involuntary Resettlement - Rights and Interests of Vulnerable Groups

•Labour Standards

•Occupational and Public Health, Safety and Security

•Stakeholder Engagement

Again, however, as has become obvious,  the US EPA has been so reduced in skilled manpower, and the processes for using available expertise to determine environmental and social compliance with regulations may not even exist anymore.  To make it worse,  even in states where useful resources exist for managing permitting processes there are  "the EPA’s ongoing attempts to seize more and more environmental regulatory authority from the states."  Thus It seems unlikely that the permitting process can soon meet the goals of AWIA.  Maybe some time in the future.

Yes, hydropower has a great deal of potential for providing many benefits.  But it is fraught with danger and risk and few resources to mitigate that risk.  Please take this into consideration. 

John Miller's picture
John Miller on Feb 14, 2021

Mark, you have done a very good job in summarizing the complexities and pros-and-cons of possibly growing U.S. Hydropower Generation & Power Storage.  Yes, upstream and downstream ecosystems’ impacts are very important & complex, and, some of the most significant factors to why U.S. Hydropower generation capacities have basically stagnated over the past 50 years.  And, has thus far, failed to provide any significant increase in this ‘zero carbon’ power generation since the 1970’s. 

Unlike variable Wind & Solar Power generation, Hydropower generation and storage has the technical capability and advantage of directly displacing ‘baseload’ Coal Power Production.  Yes, U.S. Wind & Solar Power net generation has increased very substantially over the past decade, but has had insignificant impact on displacing baseload Coal Power generation and emissions.  The major displacement & shutdown of Coal Power generation/plants is overwhelmingly due to Natural Gas Power plants; which can operate continuously to provide required baseload power, and on-demand peaking/variable power generation as needed to continuously & reliability maintain Power Grids supply-and-demand balances, reliably 24-7.  This increasing variable Natural Gas Power generation has also enabled ‘maximizing’ variable Wind & Solar Power over the past decade.  Other than somewhat limited Hydropower Storage, developing Industrial scale power storage, such as enormous batteries, is far from developing and providing Industrial scale power storage as increasingly required by expanding variable Wind & Solar Power generation.

Possibly, although not if the same negative-potential ecosystem magnitudes as new Hydropower Plants, Wind & Solar still have significant ecosystems negative impacts also.  Besides the negative ecosystems’ impacts of the physical footprints of installing new and added Solar Power plants and Wind Power farms, both these centralized Renewable Power supplies systems also have very significant added-negative ecosystems impacts caused by new-expanded and required Power Lines/Distribution Systems.  The added-negative impacts of ‘offshore’ Wind Turbines are on marine-fish ecosystems, and, both on-land and marine Wind Turbines’ operations increasing-threatening the killing of many numerous current and future Birds’ populations.  And, the ‘full-lifecycle’ impacts of many physical ecosystems & carbon footprints of mining, fabricating-producing and installing & maintaining Wind Turbines Farms and Solar Panels Plants, and Power Lines & Distribution Systems, is and will be, increasingly significant throughout large parts of the U.S., and, Internationally.

Yes, both Wind & Solar Power generation projects, and Hydropower, should be fully evaluated to minimize negative ecosystems impacts of fabrications, installations, operations and maintenance of these ‘zero/minimal’ carbon Power Systems’ technologies.  And, optimize the costs and overall benefits.  The final decisions on issuing projects’ building permits need to address a reasonable balance between costs-and-benefits, and not be biased largely on Political Groups’ views/beliefs.

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Thank Kent for the Post!
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