Water rushes through part of a dam.
River water rushes through a dam. Credit: iStock.com/nkurtzman

In 2021, hydropower contributed 16% to total global electricity production, whereas in the United States it accounted for only about 6% of the total (although it was responsible for 31.5% of electricity generated domestically from renewable sources), according to the U.S. Energy Information Administration. That small share of U.S. production could be higher: The 2016 Hydropower Vision Report, published by the U.S. Department of Energy’s (DOE) Water Power Technologies Office (WPTO), stated that “U.S. hydropower could grow from 101 gigawatts (GW) of capacity to nearly 150 GW by 2050.”

Whether hydroelectric generation should be expanded is a point of contention, as it is not without downsides. Negative effects on waterways and associated ecosystems at and downstream of hydropower infrastructure are well documented. But hydropower operations can also provide clean and cost-effective energy, benefit flood control and irrigation efforts, help maintain water supplies, mitigate climate change, and increase the reliability of electricity production.

Despite hydropower being one of the oldest and largest sources of renewable energy in the country, there is very little publicly available or easily accessible data on the current fleet of U.S. hydropower plants.

Despite hydropower being one of the oldest and largest sources of renewable energy in the country, there is very little publicly available or easily accessible data on the current fleet of U.S. hydropower plants. Those data that are available are included in disparate data sets created by a multitude of private sources as well as by government agencies like WPTO. This limited access to data restricts the ability of stakeholders in industry, government, and research to plan, regulate, and study integrated energy-water systems, particularly at the river basin level. Such efforts require data characterizing the composition, performance, costs, market participation, and regulatory best practices of the hydropower fleet together with data covering flood regulation, hydrography, recreation, aquatic ecology, water quality, and water use.

Examining more fully the country’s potential for safe and sustainable hydropower generation requires broadening and strengthening the knowledge and engagement of the hydropower research and applications communities, which in turn requires improved access to existing data as well as new analytical capabilities. Such access and capabilities will help inform a well-designed, long-term research strategy to support the maintenance and possible expansion of the U.S. hydropower fleet; reduce its environmental impacts; and identify ways that hydropower can contribute to improved grid reliability, resilience, and integration.

In recent years, DOE’s WPTO and Oak Ridge National Laboratory (ORNL) have made significant efforts to improve the availability, accessibility, and usability of a variety of hydropower information and analytical tools by developing a novel online platform called HydroSource.

HydroSource’s Expanded Scope

HydroSource is primarily a resource for hydropower stakeholders: hydropower operators and developers; governmental (at federal, state, and local levels) and nongovernmental organizations; and academic researchers, policy leaders, and the public.

HydroSource was born out of the precursor National Hydropower Asset Assessment Program (NHAAP), which was founded in 2010, sponsored by WPTO, and located at ORNL. NHAAP’s goal was to provide data for the evaluation of existing and potential hydropower resources in the United States. It built and maintained a comprehensive database covering more than 2,000 plants nationwide. The database incorporated federal hydropower plants operated by the U.S. Bureau of Reclamation, U.S. Army Corps of Engineers, and Tennessee Valley Authority, as well as nonfederal hydropower plants regulated by the U.S. Federal Energy Regulatory Commission (FERC) and state agencies. NHAAP also produced estimates of hydroelectric potential from nonpowered dams and new stream reach developments and—as directed in the 2009 SECURE Water Act—the first report assessing impacts of climate change on federal hydropower generation.

As the nation’s energy and water systems become increasingly complex and interconnected, an expanded and more accessible data landscape helps enable robust new research and analytical capabilities.

As the scope of NHAAP expanded beyond just asset assessment, the program transitioned between 2017 and 2018 to become HydroSource. HydroSource is a comprehensive and unique national digital platform that provides dedicated stewardship and dissemination of a wide range of up-to-date scientific data (Figure 1), thus improving the “data landscape” for U.S. hydropower and river information for U.S. hydropower stakeholders.

As the nation’s energy and water systems become increasingly complex and interconnected, an expanded and more accessible data landscape helps enable robust new research and analytical capabilities. These capabilities support science-based and transparent analyses of existing hydropower projects and information (e.g., related to resource characterization and plant performance, costs, and maintenance); assessments of environmental and climate impacts and mitigation steps; and considerations surrounding the development of new projects, including permitting, hydropower market acceleration, and technology-to-market activities. They also support improved decisionmaking and policymaking for efficient and sustainable hydropower generation and for basin-wide water management of river resources for other uses as well.

Infographic showing main components of the HydroSource digital platform
Fig. 1. This infographic illustrates the main components of the HydroSource digital platform, including the types of hydropower-relevant data and tools it collects, its user-facing features (e.g., web portal), external outcomes of its use (e.g., product development), and efforts by the HydroSource team (e.g., stakeholder engagement). Click image for larger version. Credit: Adam Malin, ORNL

A Multifaceted Resource

The HydroSource data portal allows anyone to search and download published data produced by ORNL scientists and covering various spatiotemporal scales. The portal has been developed according to the FAIR (findable, accessible, interoperable, and reusable) principles, which enable data to be publicly disseminated along with standardized metadata and digital object identifiers. The HydroSource digital platform offers the following key features and benefits to users:

  • Authoritative, multidisciplinary science data on energy, water, and resource characterization and assessment, as well as on environmental, hydroclimatologic, and socioeconomic factors
  • Well-described data attributes and metadata that meet domain-relevant community standards and will aid in data discovery and reuse
  • Centralized access to integrated and derived products and tools that provide flexible and user-friendly data analysis to address scenario-specific objectives
  • Ongoing end-user engagement and coordination by the HydroSource team to support end user needs.

Data on existing hydropower plants and on future hydropower potential form the core resource of the HydroSource digital platform. The Existing Hydropower Assets (EHA) Plant database, used to develop the National Hydropower Map (Figure 2), consists of comprehensive details on the locations and key characteristics (e.g., generation or capacity) of currently operational U.S. hydropower plants. The EHA Unit database provides the locations and key characteristics of operational turbine units at U.S. hydropower plants. As demonstrated by WPTO’s Hydropower Market Report and its associated data, EHA resource assessments as well as data from external sources can be used to analyze the past, present, and projected future of the hydropower industry and trends in pumped storage development. Users often seek highly specific information about plants, so it’s important that EHA data in HydroSource can be filtered by location (hydrologic region or subregion, basin or subbasin, balancing authority) or ownership entity.

Map showing the geospatial distribution and characteristics of operational U.S. hydropower plants
Fig. 2. The 2022 National Hydropower Map provides a visualization of the geospatial distribution and characteristics (e.g., size, type, ownership) of operational U.S. hydropower plants. Click image for larger version. Credit: ORNL/U.S. DOE

Hydropower Infrastructure–Lakes, Reservoirs, and Rivers (HILARRI) is a database linking major data sets of operational hydropower dams and power plants and inland water bodies. For example, data on dams from the National Inventory of Dams and the Global Reservoir and Dam Database and on hydropower plants from the EHA data set are linked to information on water bodies from the National Hydrography Dataset and the HydroLAKES database, providing hydrologic and hydraulic information relevant for analysis of hydropower systems.

HydroSource also provides multiple resources useful for assessing new hydropower developments by way of cost-effective conversions of existing nonpowered dams (NPDs) into hydropower dams. Among these are the U.S. Hydropower Potential from Existing Non-powered Dams data set, which estimates untapped hydropower capacity and generation potentials greater than 1 megawatt for nonpowered dams, and the U.S. Non-Powered Dam Characteristics Inventory. HydroSource also provides data identifying untapped U.S. streams that could potentially generate hydropower through the Hydropower Potential from New Stream-Reach Development data set. The New Stream-Reach data differentiate stream reaches with high (>1 megawatt) or low (<1 megawatt) energy potential, and currently identify more than 100 reaches with at least 100 megawatts of potential capacity.

Ensuring that hydropower projects are designed to mitigate negative effects is essential.

Along with hydropower’s benefits, it can also have detrimental effects on human and environmental health and safety. For example, hydropower generation may obstruct fish migration and may change water temperatures, water chemistry, sediment loads, the composition of ecological communities, and river flow characteristics. Ensuring that hydropower projects are designed to mitigate such negative effects is essential. HydroSource provides data and data-based tools that can help in identifying and minimizing hydropower’s impacts. The U.S. Hydropower Mitigation Database, for example, details mitigation measures associated with hydropower plants licensed by FERC (Figure 3), and the Cost of Mitigating the Environmental Impacts of Hydropower Projects data set compiles data on mitigation costs for 182 projects from FERC documents. The Environmental Metrics for Hydropower Database further compiles 3,000 metrics used to characterize ecological effects related to water quality, biodiversity, geomorphology, and land cover and use at 231 hydropower-generating locations across the country. This resource illuminates how different metrics have previously been used across regions and different types of hydropower projects, and it can help determine metrics useful in assessing current and future projects.

Map showing environmental mitigations associated with U.S. hydropower plants.
Fig. 3. This map shows environmental mitigations associated with hydropower plants aggregated to hydrologic regions and mapped by the highest-level category from the mitigation database. Click image for larger version.

Also available in HydroSource is a data set from the 2022 Third Assessment of the Effects of Climate Change on Federal Hydropower—the follow-up to the first assessment in 2012 and the second in 2016—which reported potential effects of climate change on water availability for hydropower at federal facilities and on the marketing of power from those facilities. This data set presents high-resolution downscaled hydroclimate projections for the conterminous United States from an ensemble of general climate models from the Coupled Model Intercomparison Project phase 6. The data set provides future seasonal and monthly hydropower projections at 132 federal hydropower plants, supporting long-term planning for hydropower marketing.

Helping make sense of the large amount of data in HydroSource are various available analytic tools, as well as rich metadata collections—indexed for search and retrieval—associated with each data set, visualization, and tool. The HydroSource Data Explorer is a digital platform for integrated energy, water, and ecosystem analysis that allows exploration and downloading of all HydroSource data. Users can, for example, estimate hydropower generation and capacity by region, visualize the future hydropower potential of a basin, or analyze existing facilities and hydrology around a new development site. The U.S. Stream Classification System, which organizes 2.6 million stream reaches in the conterminous United States into groups with similar physical properties, allows users to explore and visualize streams on the basis of hydrologic and thermal regimes, size, gradient, and valley geomorphology. The Standard Modular Hydropower Explorer similarly allows for geovisual analysis useful for siting, design, development, and operation of small, low-cost, modular, and replicable hydropower facilities that preserve or enhance river function. Other tools allow exploration of data related to NPDs and potential environmental impacts of hydropower projects.

Another major benefit of the HydroSource digital platform is that it allows users to traverse multiple data sets at once, allowing for richer multidimensional analyses. Integration of the data sets through the HydroSource Data Model, which informs users on how different data mesh together and how they can be used with geographic information system (GIS) and visualization software, makes this a seamless process, adding value to the data in HydroSource.

Serving the Water Data Community

The HydroSource team proactively engages with our diverse base of hydropower end users and potential stakeholders in the water data community to understand and support their needs. For example, we regularly solicit input on their experiences, preferences, and challenges during searching, downloading, and using hydropower data products from the HydroSource digital platform. And we build partnerships with user communities—in the National Hydropower Association, national laboratories and federal agencies, nongovernmental organizations, universities, and the public—through webinars and workshops.

These capabilities will enable innovative analyses and visualizations, information exchange with other databases and repositories, and data integration into modeling and simulation efforts.

HydroSource will continue its efforts to serve a diverse user base by adding more hydropower-related data and tools. These capabilities will allow for more vigorous data mining and enable innovative analyses and visualizations, information exchange with other databases and repositories, and data integration into modeling and simulation efforts. In particular, HydroSource will support management and analysis of complex hydrology data by developing, beginning next year, a model-data integration platform to better understand the risks of long-term variations in water availability to hydropower generation and the resiliency of existing and new hydropower assets.

Furthermore, HydroSource will continue developing partnerships to expand the use of open data, promote open science, and increase the use of data across multidisciplinary, multiagency organizations. We are collaborating, for example, with the Internet of Water (IoW) Coalition, a group of independent organizations and public agencies with the shared goal of modernizing U.S. water data infrastructure, to facilitate sharing and integration of data related to hydropower resources, development, and operations. In this collaborative endeavor, HydroSource will serve as a water data hub of IoW, helping enable sustainable water resources management and stewardship.

Updating the HydroSource platform to achieve this goal will involve building cyberinfrastructure that stores well-documented and structured data and metadata; makes those data and metadata discoverable through traditional web searches and via upstream/downstream hydrologic searches using the U.S. Geological Survey’s Hydro Network-Linked Data Index; and makes those data and metadata accessible through both well-designed user interfaces and machine-consumable application programming interfaces compliant with open standards.

In sum, the advances, collaborations, and engagement initiated through the HydroSource program should greatly expand the data landscape with respect to hydropower operations, fostering robust decisionmaking for further research and for maintenance, planning, and regulation efforts toward a safe and sustainable energy security.


This article was authored by UT-Battelle LLC, under contract DE-AC05-00OR22725 with the U.S. DOE. The publisher acknowledges the U.S. government license to provide public access under the DOE Public Access Plan. The author thanks Corey Vezina from the Water Power Technologies Office for his support, input, and review on this article.

Author Information

Debjani Singh (debd@ornl.gov), Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tenn.

Citation: Singh, D. (2023), A holistic approach to hydropower data, Eos, 104, https://doi.org/10.1029/2023EO230290. Published on 21 August 2023.
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