Science News Review

Not Just Sun and Wind:

Oct 6 at 10:10pm by Aileen

Power from the seas

In this era of “peak oil” and ever more environmentally damaging methods of extracting (and using) coal, innovative R&D on alternatives and renewables have been moving forward with vigor even without massive subsidies or continued contributions to global warming.

We already know that our planet receives more energy from the sun every day than all the life forms (and human industries) could ever use, but humans haven’t yet figured out how to harvest those electrons efficiently enough to even begin to compete with green plants and their direct conversion via photosynthesis. We also know that the sun powers our atmospheric wind patterns, and have developed means of extracting electricity from that source as well. Though again, not enough.

There’s another source of power that nature provides to our planet, and which entrepreneurs and engineers have developed and are still developing. This is the immense power of gravity, and it manifests itself in regular cycles in all the oceans and seas that cover the majority of our planet. These are the tides. Tidal generators are located beneath the surface of the water, and have to deal with both the corrosive effects of salt and other minerals in the water as well as various other contaminates, including forms of sea life. Still, the French have been generating about 600 million kilowatt hours of tidal power annually at Rance for more than 30 years. So far the moon hasn’t stopped exerting its gravitational energy on the earth!

Even as those issues are being addressed with ever more clever designs, there’s yet another ocean-born form of energy to be tapped for generating electricity – waves. Energy COOL: Swell Electricity from the Sea talks about how inventors are harnessing the waves in ways that could represent world-changing applications.

These wave-power inventions – some are generating electricity as we speak – are starting to get mainstream press attention. The Washington Post reported on a technology called AquaBuOY from Finavera Renewables in September, quoting its CEO as saying:

Finavera’s chief executive, Jason Bak, believes he knows how. The equipment his company designed, called AquaBuOY, aims to generate electricity from the vertical motion of waves. The buoy, anchored in an array two to three miles offshore, will convert the waves’ motion into pressurized water using large, reinforced-rubber hose pumps. As the buoy goes up the peak of a wave and down into its trough, it forces a piston in the bottom of the buoy to stretch and contract the hose pumps, pushing water through. This drives a turbine that powers a generator producing electricity, which would be shipped to shore through an undersea transmission line.

“This is the new source of power,” Bak said. “It’s the highest-energy-density renewable out there. Wind is like light crude oil, and water is like gasoline.”

Perhaps that’s a little overboard, but Finavera’s not the only development company out there…

• Pelamis Wave Power has a snake-like device moving from test-level to commercial production of the Iberian Peninsula and in the UK.
• Verdant Power is testing its systems off coast of Manhattan. There are some new-technology problems, but they’re being addressed.
• Ocean Power Technologies has another buoy power system design. They are testing projects in Hawaii, Spain and New Jersey.
• Swell Fuel has the ‘Ocean Energy Converter’ float device that generates electricity from the swell flow in any direction, and is setting up test projects off El Salvador, Guatemala, Honduras, Nicaragua and Belize.

Check out some of the links below to get the latest on what’s what with various forms of renewable power sources and developing technologies to tap them.

Links:

Energy Cool

Energize America

Energy Smart