Oceans cover more than 70% of Earth’s surface, yet for decades no one had mapped their energy potential at a truly global scale. Regional studies existed, but a comprehensive picture built on real-world measurements was missing — leaving one of the planet’s largest clean energy resources largely uncharted.
Now, a study drawing on more than 30 years of satellite-tracked buoy data has begun to fill that gap. As electricity demand climbs worldwide and pressure mounts on conventional energy sources, researchers set out to answer a question that had never been fully resolved: where, exactly, does the ocean generate enough force to produce meaningful power?
A 30-year dataset finally fills a global gap
Before this study, researchers had to rely on regional snapshots — isolated assessments that could not be stitched together into a coherent global picture. No single evaluation had used real, measured ocean data to rank current energy potential worldwide, leaving engineers and policymakers without a reliable foundation for investment or planning.
Florida Atlantic University researchers turned to NOAA’s Global Drifter Program to address that. The program operates roughly 1,250 satellite-tracked buoys that continuously record current speed and position across the world’s oceans. More than 43 million data points were extracted from measurements collected between March 1988 and September 2021 — three decades of continuous data from instruments spread across every major ocean basin.
Published in the journal Renewable Energy, the resulting study is described as the most comprehensive global assessment of ocean current energy to date. Researchers focused specifically on kinetic energy — the force generated by moving water — calculating power density and tracking how it shifts by location and season. Nothing attempted before matched this combination of scale and data quality.
Florida and South Africa rise to the top
The headline result is striking. Waters off Florida’s East Coast and South Africa consistently registered power densities above 2,500 watts per square meter. A resource is classified as “excellent” for wind energy at around 1,000 watts per square meter — these ocean currents deliver roughly 2.5 times that benchmark.
The strongest zones extend well beyond a single point on the map. Along the U.S. coastline, a corridor from Florida up to North Carolina showed persistently high densities. Along Africa, the high-performing band runs from Somalia and Kenya in the east, down through Tanzania and Madagascar, into South Africa’s southeastern waters.
Shallow water depth adds another advantage. In the most promising areas, the seafloor sits at roughly 300 meters — manageable for turbine installation compared to the abyssal depths found elsewhere. That pairing of strong currents and accessible depth makes these regions particularly attractive for developers weighing where to deploy ocean current turbines.
Where the ocean underdelivers — and why
Not every region with visible surface currents translates into a practical energy resource. The Eastern Pacific — including waters off Japan, Vietnam, and the Philippines — shows lower power densities at comparable depths, and northern South America and the eastern coast of Australia follow a similar pattern.
Depth is a recurring obstacle. Where strong currents exist but water plunges to 1,000 meters or more, engineering challenges multiply fast. Turbines require advanced mooring systems to stay stable, and installation and maintenance costs rise sharply with depth. Parts of Japan and South Africa combine high surface power densities with exactly these deeper, more demanding conditions — making them harder to develop despite their apparent promise.
The moderate middle ground still warrants attention. About 75% of high-power-density ocean areas — covering roughly 490,000 square kilometers — fall in the 500 to 1,000 watts per square meter range. Below the exceptional levels seen off Florida and South Africa, yes, but still significant for sustainable energy production at scale.
Seasonal rhythms that match peak demand
One of the study’s more practically useful findings involves timing. In the Northern Hemisphere, power densities off Florida, Japan, and northern Brazil tend to peak between June and August — a window that aligns directly with summer months, when air-conditioning demand drives electricity consumption to its highest levels of the year.
South Africa’s pattern mirrors the same logic from the opposite hemisphere, with peak densities arriving during December through February, the region’s warmest months, when local demand climbs accordingly.
This seasonal alignment matters more than it might first appear. Many renewable sources generate power when the grid does not need it most. A resource that naturally intensifies alongside demand peaks offers a genuine grid integration advantage — and researchers highlight this quality as a meaningful argument for treating ocean current energy as a reliable complement to other renewables, rather than an intermittent source requiring heavy storage backup.
Data gaps and the road to reliable ocean power
The study is comprehensive, but not complete. Energy estimates for North America and Japan carried high reliability, supported by dense data and confirmed against independent measurements. South Africa and parts of northern South America — particularly off Brazil and French Guiana — presented more uncertainty, a result of sparser data and highly variable water conditions.
Researchers recommend targeted follow-up work using acoustic Doppler current profilers, instruments capable of measuring current velocity at multiple depths simultaneously. Region-specific data of that kind would sharpen energy production estimates and give turbine designers the detail needed to move from concept to deployment.
Expanding data collection in under-assessed regions is now a clear next step. The study was supported by the National Science Foundation, the U.S. Department of Energy, and FPL InETech at FAU — backing that signals real institutional appetite for advancing this research.
As ocean turbine technology matures and pressure to diversify clean energy sources grows, the locations this study identified will likely become the focus of serious feasibility work. The global map now exists. The next question is who builds first.
Carlos is an engineer with strong expertise in technical and industrial topics. He previously worked at international companies such as Siemens and speaks Spanish, German, English, and Italian.
