World energy: Tapping the power of the sea
THE ECONOMIST, 14 May 2007
An effort to harvest electricity from tides and waves is gathering pace
IF ONLY a few little problems, to do with politics, government regulation and technology, could be solved, then the remedy for the world's fossil-fuel dependence would be wonderfully simple: just look to the ocean. A fraction of the energy locked up in the oceans could, in theory, meet the world's entire electricity needs.
In practice, of course, things are nothing like that simple. Extracting hydropower from dammed-up rivers is comparatively easy compared with harvesting energy from offshore tides and waves, and then putting it into the grid via underwater cables. Only 14 countries now operate tidal or wave-power stations, and most are tiny, experimental and expensive.
But with governments all over the world thinking about climate change, and under pressure from voters to show their green colours, the tide may be turning, politically at least. Australian scientists fantasise about the day when they could get enough power from the surf-friendly waves along the southern coast to meet the whole country's electricity needs. Politicians in Oregon dream of generating all the state's power from the Pacific. Britain's Carbon Trust, a government-funded company that proffers help with cutting greenhouse emissions, says 20% of national energy could come from the sea.
Compared with those dreams, anything that is really happening, or likely to happen in the near future, sounds puny. Technology piloted at the European Marine Energy Centre, a testing ground in the storm-tossed Orkney islands off northern Scotland, will soon be used to supply the Portuguese national grid. But the device that will be set up by Ocean Power Delivery, a Scottish company, off Portugal's coast is not (or not yet) going to change the world; initially it will provide 2.25MW of electricity, enough for around 1,500 homes, and later ten times as much. A "wave farm" off Cornwall will soon supply 7,500 English homes.
Meanwhile, America's first tidal project became operational last December, when two underwater turbines were installed in New York's East River. It took Verdant Power, a Canadian-American company, five years to get the necessary permits--in part because this tiny project faces as big a regulatory burden from federal authorities as a giant conventional power station.
But the climate may be shifting. A legislator from Washington state this week urged Congress to spend at least $50m on ocean-power research: not world-beating, but potentially the first federal funding in decades for sea-based renewables.With its fossil-fuel culture, the United States is a laggard in marine energy. Tidal power projects have been in place for more than 40 years in China, Russia and also in France, where a tidal unit on the Rance river claims to produce energy more cheaply than nuclear power stations.
Canada established a tidal-research station in its eastern Bay of Fundy, said to have some of the best tidal resources in the world, in 1984. This uses an old technology, called barrage (blocking the tide), but the Nova Scotia government hopes to have new machines in place by 2009.Many other governments are interested in marine power but want to see whether other states shoulder the financial risks, says Michael Hay, of Britain's Wind Energy Association: he mentions Ireland, Spain, South Africa, Australia, New Zealand, China and South Korea.Hunter Lovins, an energy economics pundit, says the financial obstacles to widespread marine power may trump the political attractions. "Absent a global recognition of the extreme seriousness of climate change, tidal's not really a player." she says. But is there such an absence?