Scholars discuss pathways to scalable ocean-based energy sources.
Global electricity consumption in 2024 rose by more than twice the average annual amount over the last decade, and experts expect this trend only to increase with the development of artificial intelligence (AI). Because energy production already accounts for roughly 75 percent of global greenhouse gas emissions, the incoming boom in energy demand could have devastating effects on the climate if sustainable solutions are not found.
One potential route for increasing the supply of sustainable energy would be to scale up marine-based renewable energy, argues Enwei Tang of China’s Dongguan University of Technology and several coauthors in a recent article.
Scientists use “marine renewable energy” as a catchall phrase to refer to renewable energy sources that are either built at sea or use an aspect of the ocean to produce energy.
Offshore wind energy is the most common and well-developed marine renewable energy source, but other examples include offshore solar, tidal, wave, ocean current, ocean thermal, marine biomass, and salinity gradient energy. Tang and her coauthors contend that marine-based energy sources have several inherent advantages over terrestrial-based energy that could make marine renewable energy the future of sustainable energy.
They argue that the primary advantage of marine renewable energy is that it falls outside the scope of national land-use regulations. They claim that land scarcity drastically slows and limits the development of terrestrial renewable energy, whereas the marine environment offers exceptionally vast development spaces for large-scale projects.
Tang and her coauthors estimate that, if all types of marine renewable energy were operating at full projected capacity, they would produce a combined 112,000 terawatt hours of energy in a year—approximately 427 percent of the global energy demand in 2024.
They note, however, that despite the advantages of these various technologies, most of them are still in the early stages of development. In 2024, offshore wind accounted for 90 percent of marine renewable energy only produced 75.2 gigawatt hours.
Tang and her coauthors found four major roadblocks that account for the slow development of marine renewable energy.
Most marine renewable energy sources produce energy at inconsistent rates. This variability results in large fluctuations between energy shortages and surpluses that make marine renewable energy sources risky investments until reliable battery technology is developed.
The harsh natural environment of the ocean adds another layer of difficulty to building marine renewable energy projects by increasing the installation, operation, and maintenance costs of the infrastructure to account for the corrosion caused by the sea water.
Development is further constrained by the lack of high-quality meteorological data, which is necessary for predictive models to determine the best locations for marine renewable energy projects to be built.
Finally, the potential for negative environmental impacts, such as disturbing the local marine ecosystems, underlies any proposed infrastructure development. Adverse effects from marine renewable energy sources need to be researched at length before any projects can be deployed.
Tang and her coauthors provide several recommendations for how marine renewable energy could be pursued and scaled up while addressing these roadblocks.
To mitigate fluctuations in energy production without relying on battery technology, they recommend that governments focus on developing hybrid renewable energy systems. A hybrid system is a single development that integrates multiple methods of renewable energy generation, such as combining offshore wind with tidal energy. This would reduce the fluctuations in energy output and increase the total amount of output per unit of offshore space.
Alongside the hybrid energy systems, they propose combining energy developments with other marine-based technologies so surplus energy can be used more productively. Excess energy could be used in electricity-to-gas conversion technology to store the excess energy as hydrogen for future energy production, or the excess energy could power desalination plants to create freshwater. Turning any excess energy into an additional product increases the economic viability of the project, which makes investments into these projects less risky.
Environmental concerns can be partially addressed by coupling marine renewable energy infrastructure with marine aquaculture projects. They contend that the infrastructure developments could function as artificial reefs to support aquatic life or could be used as macroalgae farms to grow biofuels.
Finally, they advocate the integration of artificial intelligence into marine renewable energy planning for regional energy potential assessments and for power generation forecasting. These tools could reduce the need for better meteorological data while improving the allocation of resources to help lower costs and encourage the development of larger marine renewable projects.
Marine renewable energy might well be able to help solve the global energy crisis, but Tang and her coauthors argue that it is not getting the support it needs from the public or private sectors. By adopting the strategies that they recommend, marine renewable energy might become a strong enough economic investment to support large-scale deployment and reach its full potential.
