Power can be generated from the flow of water in river currents, tides, and ocean waves.
Technology for in-stream hydropower is still developing to operate in varying conditions.
In the U.S., one currently operating hydrokinetic energy project powers an Alaskan village, and two test sites will come online in the next year.
While conventional hydropower relies on the movement of water from higher to lower elevations to generate electricity, energy can also be harnessed from the movement of water alone. This type of energy, known as hydrokinetic energy, has three sources: rivers, tides, and ocean waves (VanZwieten et al. 2014).
Compared to conventional hydropower, hydrokinetic power has lower infrastructure requirements and is less environmentally intrusive (Gutenson et al. 2023). Power is generated by placing a turbine in the path of the natural flow of water, either anchored to the river or ocean bed or mounted on a floating platform (VanZwieten et al. 2014). Hydrokinetic energy also has a more stable and predictable availability compared to other renewable resources. This can be useful for low, consistent power generation in remote areas (Awandu et al. 2024, Zhang et al. 2021).
Hydrokinetic energy technology emerged in the 1990s, and the first U.S. project was installed in 2009 (Ibrahim et al. 2021, VanZwieten et al. 2014, Tethys n.d.a). While some designs are fully developed, many are still prototypes and under development (Malali et al. 2025). Researchers must account for economic feasibility and varying real-world operating conditions when designing hydrokinetic energy devices.
Local river conditions present a challenge for deploying hydrokinetic turbines. These devices typically require at least 6 feet of water depth, limiting installation locations (Kirke 2024). Because faster water currents create more power, lower flow velocities present challenges for turbines to efficiently generate power (Ibrahim et al. 2021). Other factors that impact turbine placement and function include the amount of sediment and debris, temperature, and turbulence (Kirke 2024, Neary et al. 2011). Geographic information systems and modeling of river conditions can take these factors into account to analyze where hydrokinetic energy is feasible (Gutenson et al. 2023, Kirby et al. 2021).
In the U.S., the Federal Energy Regulatory Commission (FERC) authorizes and regulates hydropower projects. FERC issues preliminary permits for collecting data and studying the feasibility of a proposed project, and licenses for constructing and operating new projects (FERC 2016). As of December 2025, FERC has issued eleven active permits and licensed three hydrokinetic energy projects (Figure 1, FERC 2025).
The Igiugig project in Alaska is the oldest continuously operating hydrokinetic energy project in the U.S. (FERC 2025, Tethys n.d.b). Installed in 2019, the system is located on the Kvichak River and supplies power to the indigenous village of Igiugig, lowering the local demand for diesel-fueled power (Hill 2023, Tethys n.d.b). Although the region has a large salmon population, several years of monitoring found the power system had no impact on the fish.
The other two projects with active licenses are currently in development. Both are intended as test sites for new turbine designs in real marine conditions (Rogers 2025):
Most hydrokinetic projects with preliminary FERC permits are focused on tidal energy and are located along the coasts in Alaska, Washington, or the Northeast. However, three projects focused on inland river currents have been permitted: one on the Niagara River in New York and two along the lower Mississippi River.
See the Hydropower and Small Scale Hydropower Science Notes for more information.
Figure 1. Hydrokinetic energy projects with permits or licenses from the Federal Energy Regulatory Commission (FERC). These projects focus on generating power from the movement of rivers, tides, and ocean waves. Permits are granted to research and plan a project at the location, while licenses are granted to build and operate a hydropower project. Note that there are two overlapping projects in both New York and Maine. Figure adapted from FERC 2025.
References
Awandu W, Wiesemann J-U, Lehmann B (2025) Application of low-cost hydrokinetic technology for accelerating electricity access to rural areas in developing economies: Field experiment in Kenya. Environmental Research Communications. 7: 015024. https://iopscience.iop.org/article/10.1088/2515-7620/ada8fe/meta
Federal Energy Regulatory Commission (FERC) (2025) Hydrokinetic Projects. https://www.ferc.gov/licensing/hydrokinetic-projects
Federal Energy Regulatory Commission (FERC) (2016) Hydropower Licensing – Get Involved: A Guide for the Public. https://www.ferc.gov/sites/default/files/2020-04/hydro-guide.pdf
Gutenson JL, Staebell KA, Wahl MD, Petri AC, Duczynski M (2023) A practical evaluation of micro-hydrokinetic power potential for the Continental United States. Journal of Hydrology: Regional Studies. 47: 101402. https://doi.org/10.1016/j.ejrh.2023.101402
Hill K (2023) A resilient and autonomous microgrid powered by marine renewable energy. U.S. Department of Energy. https://www.energy.gov/sites/default/files/2023-12/Village-of-Igiugig-Alaska-2023.pdf
Ibrahim WI, Mohamed MR, Ismail RMTR, Leung PK, Xing WW, et al. (2021) Hydrokinetic energy harnessing technologies: A review. Energy Reports. 7: 2021-2042. https://doi.org/10.1016/j.egyr.2021.04.003
Kirby K, Ferguson S, Rennie C, Nistor I, Cousineau J (2021) Assessments of available riverine hydrokinetic energy: A review. Canadian Journal of Civil Engineering. 49(6): 839-854. https://doi.org/10.1139/cjce-2021-0178
Kirke B (2024) Towards more cost-effective river hydrokinetic turbines. Energy for Sustainable Development. 78: 101370. https://doi.org/10.1016/j.esd.2023.101370
Malali P, Ding Z, Villavicencio MA (2025) Technology readiness level assessment of hydrokinetic energy converters. Energy Reports. 14: 1240-1250. https://doi.org/10.1016/j.egyr.2025.06.055
Marine Renewable Energy Collaborative (2021) Bourne Tidal Test Site. https://www.mreconewengland.org/marine_renewable_energy/wp-content/uploads/2022/01/BTTS-Flyer-2021.pdf
Neary VS, Gunawan B, Richmond MC, Durgesh V, Polagye B, et al. (2011) Field measurements at river and tidal current sites for hydrokinetic energy development: Best Practices Manual. Oak Ridge National Laboratory. https://doi.org/10.2172/1034380
Ridgill M, Lewis MJ, Robins PE, Patil SD, Neill SP (2022) Hydrokinetic energy conversion: A global riverine perspective. Journal of Renewable and Sustainable Energy. 14: 044501. https://doi.org/10.1063/5.0092215
Rogers K (2025) How U.S. marine energy test sites are driving innovation. National Hydropower Association. https://www.hydro.org/powerhouse/article/how-u-s-marine-energy-test-sites-are-driving-innovation/
Tethys n.d.a Lock and Dam No. 2 Hydroelectric Project. https://tethys.pnnl.gov/project-sites/lock-dam-no-2-hydroelectric-project
Tethys n.d.b Igiugig RivGen Power System. https://tethys.pnnl.gov/project-sites/rivgen-power-system
VanZwieten J, McAnally W, Ahmad J, Davis T, Martin J, et al. (2014) In-stream hydrokinetic power: Review and Appraisal. Journal of Energy Engineering. 141(3). https://www.osti.gov/pages/biblio/1263861
Zhang L, Pang M, Bahaj AS, Yang Y, Wang C (2021) Small hydropower development in China: growing challenges and transition strategy. Renewable and Sustainable Energy Reviews. 137: 110653. https://doi.org/10.1016/j.rser.2020.110653
