Watts from the sea

Off the western coast of Scotland, on the Isle of Islay, science teacher Ray Husthwaite turns on the light in his classroom.

The electricity comes from a power cable that runs to the mainland.

But it also comes from the ocean.

A few miles from the school, wave action compresses and decompresses air in a chamber. The moving air powers a turbine, which generates electricity.

"It is pleasant, on a choppy but sunny day, to sit beside the gray, concrete structure and listen to the rising and falling of the waves, driving air through the turbines like the breath of a great sea monster," Husthwaite said. "It seems insane to me to be investing in nuclear power stations and gas turbines when there are endless, free energy resources in the rivers, oceans and the wind."

In a world addicted to fossil fuel, turning waves into watts might seem far-fetched. But as the U.S. and other countries look for alternatives to oil, natural gas and coal and try to curb global warming, ocean power gradually is joining the ranks of wind and solar power as a source of renewable energy.

Pacific Gas & Electric Co. caught the wave last month when it became the first California utility to file for permits to study the promise of sea power, a non-polluting but expensive and mostly untested way to take energy from the ocean.

PG&E's proposed projects could provide electricity for tens of thousands of homes, said Keely Wachs, spokesman for the San Francisco-based utility. "More importantly, it's clean and totally renewable."

PG&E joins a global list of organizations experimenting with harnessing ocean power. In less than three years, U.S. energy regulators have received nearly five dozen applications for water-related energy projects from South Florida to Washington state.

Islay's wave-power converter, the Limpet 500, has been operating since 2000. In Hawaii, the Navy has been churning up electrons with the help of a floating buoy. And in Portugal, engineers are installing snakelike tubes designed to convert the sea's motion into electricity.

"We're going to decide one way or another to displace the use of fossil fuel by clean fuel," said Roger Bedard, ocean energy leader at the Electric Power Research Institute, a utility industry think tank in Palo Alto. "And our grandchildren are going to understand the consequences of that decision."