Focus On: Tidal Energy

Tidal power has always been one of our favorite ideas, and now it’s starting to evolve from cool theoretical concept to a practical source of energy.

Ocean Power Technologies is one of the front-runners here, with ongoing projects in Australia, Spain, two in the United Kingdom, Hawaii, New Jersey and two in Oregon.

Most of these are small deployments, mainly to test the technology, but the Oregon projects are noteworthy because they are slated to be full-scale, commercial power wave parks. In Coos Bay, OPT has proposed installing up to 200 of its PowerBuoys about 2.7 miles offshore, enough to generate up to 100 MW – the company says this will be the largest wave-power plant in the world.

Not far up the coast, in Reedsport, OPT expects 10 PowerBuoys offshore. It’s currently waiting for all the necessary federal permits; if it actually happens, it will be the first such commercial wave power site on the West Coast.

OPT has been testing the PowerBuoy near Atlantic City for more than two years, but the energy produced is simply dissipated. (These are big machines – see the pic above.)

Wave power is simple, in theory, but really hard to pull off. Like windmills, these systems convert kinetic energy into electricity. As the tide and waves move, the PowerBuoys move up and down, generating power.

Tide power has some key advantages over other green energy concepts. The tides, they never stop, so there’s a seemingly infinite supply here, and it could be more consistent than wind power. Plus, the tide is everywhere, so tidal power systems could be installed in a wide variety of sites.

But the sea is a very tough environment. Water and salt don’t mix well with electricity, metal and electronics, and it’s tough to send out a maintenance crew. But OPT’s systems seem to be holding up over time, so maybe we’ll see more of these. In fact, despite these not-so-trivial challenges, the main hurdle may not be the technology, but the regulatory process (see Cape Wind).