The Seabased solution produces energy even when waves are small.

The Seabased solution produces energy even when waves are small.

Renewable energy advocates have long eyed the possibility of capturing the power of ocean swells and breaking waves, but finding practical technologies at the right price has been an elusive pursuit. Until now.

Among the technical hinders are that swells move relatively slowly and the size of breaks varies dramatically according to weather, season and other factors. Making wave power a feasible economic proposition requires efficiency under widely and rapidly changing conditions.

The Swedish company Seabased approaches the problem with a unique permanent magnet, linear generator attached to the ocean floor, driven by a buoy on the surface that rises and falls with the waves.

“I received a phone call from Professor Mats Leijon about six years ago,” says Seabased CEO Billy Johansson. “He asked if I was interested in joining the board of a start-up he was planning. I was immediately interested, because I’d worked with Mats at [the Swedish-Swiss engineering conglomerate] ABB, and I knew that he had great ideas for technical solutions.”

But that enthusiasm was quickly dampened when Billy heard that the new company was working on wave energy. “My initial reaction was, ‘Forget it’,” he says. “Wave energy will never work.” But because it was Mats Leijon asking, Billy agreed to listen, and he liked what he heard. “I went for a visit the following week, and when I heard how this technology would work, I signed on to the board and took over as CEO in 2005.”

Wave energy parks are constructed in modules, and power is produced as soon as the first generator is in place.

Wave energy parks are constructed in modules, and power is produced as soon as the first generator is in place.

Energy supply is probably the central topic of the modern environmental debate. The widespread increase in living standards that has flowed from globalisation in recent decades is generally a positive development, but at the same time it means more demand for electricity. And if we’re to avoid a climate catastrophe, that new power has to come from sources that don’t cause carbon dioxide emissions

Wave power can be an important piece of the renewable energy puzzle, especially in combination with wind power. Placing the two types together in parks at sea partially solves one of the big limitations of wind generators: that electricity is generated only when the wind is blowing. Waves are of course created by wind, but swells keep rolling long after the wind dies down. In effect, waves are a storage system for wind power.

The potential total capacity for wind power worldwide is estimated at 10,000 to 15,000 TWh per year. With more efficient generators of the type developed by Seabed, that number could be raised dramatically, because power can be generated even when waves are small.

Published in February 2009