Oceans of Opportunity

September 8, 2008

Ken Silverstein, EnergyBiz Insider
Editor-in-Chief

Ocean Renewable Power Co. says that the waters off Maine's coastline will provide the foundation by which it can spawn a new generation of electricity. Its project there will start small and build over time. In the long term they say that the plant, to be placed in the Passamaquoddy Bay, would produce as much as 20 megawatts.

As the world's largest solar collectors, oceans generate thermal energy. The motion is unending and can therefore be more predictable than other renewable energy forms. Moreover, seawater is 832 times as dense as air, providing a six mile-per-hour ocean current with more kinetic energy than a 217 mile per hour wind, say experts. To bring the idea into the mainstream, however, scientists and engineers must still show that their work can be done on a large-scale basis.

"A relatively minor investment today can stimulate a West Coast industry generating billions of dollars of economic output and employing thousands of people while using an abundant and clean natural resource," says Roger Bedard, ocean energy leader with Palo Alto-based EPRI. "Surely, it's worth taking a look at what can be achieved."

Indeed, the California, Oregon and Washington State coastlines are potentially rich sources of ocean power. Alaska may be the plushest area in this country while Canada is also a plentiful spot. EPRI, the research arm of the electric utility industry, has said that ocean power in Maine has the possibility of producing electricity that does not emit harmful pollutants at a cost that is potentially on par with wind and solar energy.

EPRI goes on to say that unlike hydropower, ocean energy does not require the permanent impediment of water flow and the subsequent harm to aquatic life. Existing wave and tidal plants, it adds, impound the water before releasing it into generators.

Newer tools are even more progressive and use underwater turbines that ultimately connect to cables to transport the power. While the technology has arrived, the costs must come down and reliability must improve. Right now, a number of prototypes are being tested not just in this country but also overseas in the British Isles, Italy and Portugal. Existing tidal power plants include a 240 megawatt facility in France, a 20 megawatt plant in Nova Scotia and a 0.5 megawatt one in Russia.

According to Erik Swenson, partner in the law office of Fulbright & Jaworski, there are at least three distinct types of kinetic energy that can be harnessed in the ocean: waves, tides and currents. Waves are powered by the wind. Tides are powered by gravitational forces exerted by the sun and moon. Currents are powered by solar energy, transporting heat from the earth's equatorial regions to the colder polar regions.

"None of these sources of power are, in fact, 'constant,'" says Swenson. "Wave energy is the least so, with storms having been responsible for the failure of many an effort to harness such energy."

Don't Oversell

The key point that Swenson and other experts in this area make is that ocean power may have its place in the overall energy mix. It's just that it cannot be oversold and that its shortcomings must be analyzed upfront. That is, it's an intermittent fuel source and must be backed up with other more conventional energy forms.

That realization, in turn, leads to separate questions about whether the electrical grid should be maintained so that an expensive and spotty fuel should take priority over proven energy sources. None of this is to say that ocean power does not have its advantages: the fuel is clean, cheap and plentiful while the actual plants are underwater, although they can impede sea life.

For their part, marine power developers smell opportunity. The Federal Energy Regulatory Commission, in fact, is considering a streamlined permitting process for units that would not be placed in sensitive areas. Along those lines, it has issued dozens of permits to build such facilities in recent years. Developers tell regulators that their equipment needs to be tested in the waters where it will reside -- all to expedite commercialization of this nascent technology.

Pacific Gas and Electric is the first major utility to file a permit. It is considering a tidal plant underneath the Golden Gate Bridge. Meanwhile, Con Edison is providing power to a grocery store and parking garage from underwater turbines in New York's East River. Others are working hard to bring their projects on line, leading EPRI to predict that one day ocean power may provide 10 percent of the energy needs for those residents in the higher latitudes where it can be most effectively utilized.

"The development of this new type of energy resource, which generates electricity from the movement of water near the surface of the ocean, is one of the many sources of clean, non-polluting, renewable energy that PG&E is aggressively pursuing," says Fong Wan, PG&E's vice president of energy procurement.

The energy world awaits its conclusions. Researchers already know that ocean energy is more predictable than wind or solar power. But they are still grappling with how much those facilities will actually cost to build and maintain as well as to configure them with the electrical grid. If the current tests, though, are proven successful then some wide-scale projects may not be far off.

More information is available from Energy Central:

• Generation Technologies Topic Center

• The Power of the Tides, EnergyBiz, March/April 2007

• The Promise of Wave Power, EnergyBiz, March/April 2005