Tidal Power From Ocean Currents: The Most Reliable Renewable?
December 16, 2025
A rig tests the waters for tidal power off Alderney in the English Channel. Credit: Neil Howard, FlickrCC.
Dear EarthTalk: Where do we stand with generating energy from ocean currents? Is this a feasible option in the future? —Maisie Connors, Somerville, MA
As climate change and growing electricity demand spark the search for new renewable energy, researchers have been recently looking at the ocean for answers. Among many promising marine energy solutions lies ocean currents, which are under exploration to hopefully supply renewable electricity on a grand scale.
Driven by wind, temperature, and salinity changes, ocean currents are vast, continuous movements of seawater. Unlike other popular renewable sources such as wind and solar, ocean currents are extremely consistent and predictable, providing a more stable flow of energy. In addition, since water is about 800 times denser than air, even slow-moving currents contain enormous amounts of kinetic energy, making them a particularly attractive resource for energy generation.
Recent research led by Florida Atlantic University (FAU) has identified the east coast of Florida and the waters off South Africa as two of the world’s most promising regions for ocean current energy. Due to their high power densities above 2,500 watts per square meter, ocean current energy could be both technically and economically viable, suggesting that this method is feasible in the right places.
The technology usually involves large underwater turbines anchored to the seafloor, which generate electricity as the current turns their blades. Currently, most projects still lie in the demonstration and pilot stages, and only a few ongoing initiatives supply energy to local grids.
The main obstacles are economic. Building, deploying, and maintaining underwater infrastructure can be very costly, especially when dealing with deep or turbulent waters. Moreover, transmitting electricity from the ocean to land power grids can be costly, making the energy source less cost-competitive than its more mature wind and solar alternatives.
Nonetheless, ocean currents hold high potential. Dr. Mahsan Sadoughipour, lead author of the FAU study, notes, “About 75% of the total high-power density areas, covering around 490,000 square kilometers of the ocean, have energy levels between 500 and 1,000 watts per square meter. This suggests there’s a lot of potential for harvesting energy from ocean currents, especially in regions where power densities are moderate yet significant for sustainable energy production.”
Many countries around the globe are beginning to explore and create new innovations to harness ocean currents. In Japan, a 330-ton prototype turbine in the Kuroshio Current produces 100 kilowatts of power and is expected to be commercially deployed by the 2030s. To help usher in ocean current energy, individuals can play an important role by staying informed about promising sustainable ocean usage support and advocating for supportive policies on a local, state, and federal level.
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