Oceans are a vast reservoir of energy, and with the progression of technology, waves and tides have emerged as promising sources of renewable power in the global effort to move away from fossil fuels. Water covers over two-thirds of the Earth’s surface, with the oceans holding 96.5% of it. Although patents for water-powered devices date back over 200 years, recent energy and climate crises have renewed interest in water power generation, opening new avenues for its development.
The vast energy potential stored in ocean waves and tides is now the target of innovative projects aiming to efficiently harness and convert this power for widespread use. The proximity of most of the world’s population to coastlines makes ocean energy an attractive alternative to traditional, polluting forms of energy. According to the European Commission’s Maritime Affairs and Fisheries division, wave energy is the planet’s largest untapped renewable resource, with the potential to generate around 30,000 terawatt hours of energy annually—more than enough to meet current global electricity demand. However, only a fraction of this energy can be realistically converted due to technological and geographic limitations.
Accurately measuring the energy potential in the oceans is a complex task. Extreme natural events, like hurricanes, provide a glimpse of the immense power contained within ocean waters. For instance, a typical hurricane can release energy far exceeding the world’s annual electricity production. To assist in planning large-scale wave and tidal projects, the U.S. Department of Energy is developing more refined methods for calculating ocean energy potential. A 2023 study revealed biases in earlier estimates, suggesting they may have been inflated by 25% to 40%. Despite this, the available energy is still considerable, even if only a small percentage is feasible for conversion.
Efforts to tap into wave and tidal energy are aligning with global initiatives for renewable energy expansion. The United Nations recognises clean energy as vital to combating climate change, and with current trends, a significant portion of the global population will still lack access to electricity by 2030. Meanwhile, the energy sector is responsible for the majority of greenhouse gas emissions in the EU, which is pushing for ambitious climate targets. By 2030, the EU aims for 42.5% of its energy to come from renewable sources, including ocean energy, which is projected to generate 1 gigawatt of power by that time and expand to 40 GW by 2050.
Countries like Portugal, with its extensive coastline, are particularly well-positioned to exploit ocean energy. In fact, the country has set an ambitious goal to produce 85% of its energy from renewable sources by 2030. Portugal has already made strides in ocean energy with the installation of Finland-based AW-Energy’s WaveRoller technology, which generates electricity from panels anchored offshore. Similarly, Eco Wave Power is constructing a wave energy capture facility in Porto, which will eventually produce up to 20 megawatts of power and feature an underwater energy museum.
Globally, tidal energy projects are also expanding. The MeyGen project, located in Scotland’s Pentland Firth, is a prominent example, with its first phase producing 6 gigawatt hours of electricity in 2018, and subsequent phases increasing output. As the project expands, its environmental impact is closely monitored. In early 2023, MeyGen reached a significant milestone by generating 50 gigawatt hours of energy from tidal streams, the first array in the world to do so. With a power price guarantee secured for future expansion, the next phase of the project is set to generate another 50 MW by 2028.
However, ocean energy faces hurdles, primarily due to the high costs of equipment and construction. Achieving economies of scale requires substantial investment, and only a few companies and governments are currently equipped to take on these risks. Nevertheless, the immense potential of the oceans makes them a promising investment for sustainable energy, as demonstrated by the growing belief in projects like MeyGen, which is poised to nearly double its capacity.
While challenges remain, the ocean’s energy potential offers a promising future for renewable energy. With continued investment and technological advances, wave and tidal power could become a crucial component of the world’s energy mix.
SAE Renewables Limited (LON:SAE) was founded in 2005 as a supplier of tidal stream turbines, SAE quickly grew to include development of tidal stream projects and is the majority owner of MeyGen, the world’s largest tidal stream energy project.
