Recent studies have unveiled significant potential for harnessing renewable energy from ocean currents, presenting a viable but long-term solution to meet the increasing global electricity demands. As traditional energy sources face mounting pressure, the vast and largely unexplored potential of ocean currents offers a new avenue for sustainable power generation.
Oceans dominate over 70% of the Earth’s surface, serving as reservoirs for clean energy generation through continuous and predictable ocean currents. Unlike the more variable nature of wind or solar energy, ocean currents provide a consistent flow of energy, yet the technology to effectively harness this resource is still in its infancy.
A groundbreaking study, published in the journal Renewable Energy, was led by a team of scientists who utilised over 30 years of data collected from drifting buoys stationed globally. This analysis, comprising more than 43 million data points, has provided a clearer picture of where the strongest and most reliable ocean currents are located. The study identifies particularly promising regions, notably off Southeast Florida and South Africa, where ocean currents exhibit power densities exceeding 2,500 watts per square metre—approximately 2.5 times stronger than the best wind energy sites.
Researcher Mahsan Sadoughipour, Ph.D., commented, “Our study revealed that about 75% of high-power density areas cover around 490,000 square kilometres of ocean. Most have energy levels between 500 and 1,000 watts per square metre.” These findings suggest substantial potential for energy generation from ocean currents, especially in areas where moderate power densities are prevalent.
However, the process of capturing energy from ocean currents presents its own set of challenges. The deep waters and strong currents introduce complexities in engineering, particularly in locations such as Japan, Brazil, and parts of South Africa, where powerful currents exist but at depths that exceed 1,000 metres. James H. VanZwieten Jr., Ph.D., an assistant professor involved in the study, explained, “The depth and strength of ocean currents greatly affect how turbines must be placed.”
Variability in ocean currents also poses difficulties, as seasonal changes affect timing for optimal energy production. For example, stronger currents off the U.S. East Coast typically occur during warmer months, coinciding with increased energy demands for cooling. Similarly, South Africa experiences peak current strength in its summer months, further complicating energy planning.
The study highlights the necessity for accurate measurements to enhance the reliability of predictions regarding energy output from ocean currents. Yufei Tang, Ph.D., noted, “Regions like Brazil and South Africa have limited measurements, making predictions less certain.” Expanding data collection efforts, possibly through techniques like acoustic Doppler current profilers, could unlock more of their energy potential.
As technology advances and more data becomes available, ocean currents could significantly contribute to future energy needs. Gabriel Alsenas, director of a marine renewable energy centre involved in the study, said, “This groundbreaking research further solidifies Southeast Florida as one of the premier locations for harnessing ocean current power.” The backing of major institutions, such as the National Science Foundation and the U.S. Department of Energy, underscores the importance of developing this clean energy resource.
The study indicates that while the potential for ocean current energy is vast, realising it will require substantial investment and innovation. There is a clear call for advancements in turbine technology and equipment that can resist harsh oceanic conditions, along with careful planning to address environmental impacts that could arise from turbine installation.
As global electricity needs continue to rise, tapping into ocean energy could represent a promising and sustainable option, especially for coastal communities and islands where reliance on imported fuels remains high. But there are many hurdles to overcome.
