Marine energy projects pick up momentum

www.nytimes.com
1 Oct 2012

LONDON--Hopes of harnessing the churn and flow of the seas to generate power are pushing forward work in the small but growing tidal and wave energy industry. Despite a tough investment climate, proponents expect the technologies to begin contributing significant amounts of clean energy to power grids around the world within a decade. Tidal energy technology harvests power from the rise and fall of the sea caused by the gravitational forces of the Moon and the Sun and the rotation of the Earth. Wave power systems harness the energy of surface waves.

The immense force of the tides has long tantalized those hoping to harvest energy from them, but although a few small projects are operational, the technical barriers are high. Two distinct technologies exist--traditional dam-based plants and more recent "tidal stream" generators, built like underwater windmills. But tidal dams can be ecologically harmful while in places suitable for tidal stream plants, currents can sometimes be so strong that they risk destroying the generating turbines.

Capturing energy from waves may be even trickier. But proponents say that if wave projects are successful, the energy available for harvest would be even greater than with tidal stream power, which requires particular physical conditions, like a narrows where water runs quickly. While not as predictable as the tides, waves can be anticipated several days in advance as they move across the sea, and they tend to be strong in winter, when demand for electricity is high.

Most tidal stream power projects are still in the testing phase--the first to deliver energy to the U.S, grid went on line last month--and wave energy is even further behind. Costs are far higher than for more-established renewable sources like wind and solar, largely because equipment must be strong enough to withstand the force of the seas, and maintenance workers have to brave tough marine conditions. But "there is a huge prize, and therefore it is worth going for", said Tim Yeo, a Conservative lawmaker in the British Parliament who heads the Commons' Energy and Climate Change Committee.

The predictability and power of tides makes them a potentially valuable complement to the uncertainty of wind and solar generation, and the amount of energy available is enormous, said Mr. Yeo. His committee reported in February that wave and tidal power could eventually meet 20% of Britain's current electricity demand.

For the industry, the biggest obstacle is cost. Small projects already in existence are generating energy at five to six times the price of onshore wind power, and seven times the price of natural gas power plants, said Joe Salvatore, a renewable-power analyst at Bloomberg New Energy Finance. And the cost of installing devices has gone up, not down, as companies have learned from experience how tough their devices must be, he said.

"I'm optimistic in the medium term, I'm not necessarily optimistic in the short term", said Angus McCrone, chief editor at Bloomberg New Energy Finance. "There will be a shakeout and there will be casualties, and because of that, there will be negative publicity before there's positive publicity".

Still, costs should come down as technologies improve and equipment is manufactured on a larger scale, he said. Some big players, particularly engineering groups, are jumping into the sector. Rolls Royce bought the British company Tidal Generation in 2009 and Siemens bought Marine Current Turbines of Britain this year. The French firm DCNS has grabbed a stake in OpenHydro of Ireland.

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