For a technology that has been at the receiving end of copious government funding in various countries since the 1950s, wave power has made little progress towards financial viability compared with wind turbines and solar PV. Harnessing the might of the wind when concentrated into heaving masses of water requires such a colossal weight of hardware that the financial reward in electricity generated struggles to justify the investment required

There have been many attempts to develop wave energy technology and just as many failures. Its proneness to break down in tough weather conditions was one major issue and if it survived a storm, it did not produce enough electricity to justify its size, weight and costs, says Patrik Möller, CEO at Sweden’s CorPower Ocean, a developer of wave energy converters. The lack of agreement over any kind of standardisation also didn’t help. Unlike wind energy technology, where the industry agreed that a wind turbine consisted of a tower, a nacelle and mainly three blades, wave technology has taken on various guises. Many of these issues remain, but several of the technologies being tested at the moment look “more promising” with the potential to reap energy from the waves and be robust enough to survive a big storm, says Jens Peter Kofoed from Aalborg University, Denmark. He cites CorPower Ocean and Weptos, a Danish developer, as two companies addressing these challenges “without the use of extreme amounts of materials”. CorPower Ocean is preparing a full-scale test of its technology, which it says can survive the toughest weather conditions and produce enough energy to make it profitable. “Structural efficiency in terms of how much energy our customers can produce compared with the tonnes of equipment they need, has improved fivefold,” compared with previous best practice says Möller. A function that forces strong waves during a storm to bypass the energy buoy, leaving it intact and not ripping it apart as happened in the past is a step forward. Corrosion and damage over the longer term, however, remain sticking points, though Kofoed is confident lessons can be learned from the oil and gas industry, which has worked with these challenges for decades. CorPower Ocean has tested its technology at three different stages since 2012. First in Portugal, then in France and over the past 18 months it has tested a half-scale model in Scotland. The next step will be a full-scale test of the device, starting with one single buoy, then with another three full-scale buoys in the same location, connected with one cable. The full-scale device will then be tested for five years. The company believes it will have a bankable project by 2023 including warranties for its customers. Kofoed believes CorPower Ocean has chosen the right approach by developing the device step-by-step and testing it at every stage. Diego Pavia, CEO of InnoEnergy, an EU funded initiative supporting sustainable energy innovation, and an investor in the company’s wave technology, says this approach is vital. In the past, the tendency was to move rapidly to testing a full-scale model, losing vast amounts of money when it failed.

Less variability

Kofoed is reluctant to back 2023 as the date for commercial development, suggesting the industry has been here before, but he believes wave technology has its place in the energy transition. The density of energy in water is roughly a thousand times higher than that of air, says Daniel Kammen, a professor at Berkeley, University of California, US. “You get a thousand times more power out of your wave system.” He sees wave power “not as a dominant technology, but an ideal complement to other renewables” and forecasts that it could account for a “very important” 4-5% of global energy. Pavia agrees wave energy will not be as big as wind and solar energy in terms of produced kilowatt hours, but in terms of new installed capacity it will be a significant part of the mix by 2030, he says. In addition to its significant power, Kammen highlights the importance of wave power being less variable than wind. Areas such as California and Portugal, located on the western coasts of their continents, are challenged because there is more wind during the night than during the day, he says. “But night time demand is lower than day time demand, so finding other sources such as solar and tidal energy may be good complements.” Kofoed forecasts a palette of different renewable energy technologies working together. “Some combinations will be better in some places than in others,” he says. “Waves are not entirely correlated with wind and that is why these two energy forms can supplement each other well and together make better use of some offshore sites than if wind stood alone.” He and Kammen both see potential for combining wave energy with floating wind turbine foundations. “Wind turbines above water and wave energy technology below water, providing a ballast for the balance of the wind turbine,” says Kammen.

Financial worries

But more investment will be needed if the potential of wave is ever to become reality and private investors are still scarred by the failures of the past. Kofoed would like to see more public funding to fill the gap. “I think the commercialisation of wave technology is absolutely realistic and I think you can do it at the same cost-level as offshore wind, but there is still a lot of development work and this will not happen with just private investment. Public funding is required too,” he says. CorPower Ocean is looking to raise €24 million to fund the first stage of its full-scale testing. In 2021 it will need to raise the same amount again for the second leg. Both funding rounds will be primarily financed through public funds with private investors expected to provide approximately €6-7 million for each round, Möller says. And the need for the technology to prove its cost competitiveness is ever more challenging as prices for solar and wind installations fall rapidly. This creates a conflict, says Kofoed. The focus on time and costs mean that some developers are tempted to design smaller plants with modest capacity. “Looking to the future, big plants are needed to keep installation, operation and maintenance costs at bay, but they are expensive to test in the first place.” All this is limiting the size of the portfolio of wave technologies. “We need it to grow,” says Kammen, who hopes larger companies from the marine and boating industry will enter the wave industry and boost its growth.

Writer: Karin Jensen