Last Updated Mar 26, 2010 12:47 PM EDT
So it's something of a surprise that Scotland is willing to pour money into 10 wave and tide power projects that will cost $4 billion and generate a whopping 1.2 gigawatts of electricity -- if everything goes right.
Which it's almost guaranteed not to. Pulling energy from the ocean isn't comparable to solar power or even wind turbines, which have to deal with buffeting, unpredictable breezes. Waves are immensely powerful, they tend to destroy heavy machinery; salt water is corrosive, and marine organisms can gum up moving parts.
Even if a wave generator is tough enough to survive, there's still the challenge of generating energy cheaply. Sure, there's plenty of energy to harvest in the waves; but bulky, tough generators can become too expensive to return on investments, especially when maintenance is factored in.
The early stage the industry's in means that there are still vast differences between the various devices. Here's a cross-section of three that will be used in Scotland:
Aquamarine Power -- The company calls its machine the Oyster because of its vague resemblance to the crustacean. Instead of floating, the Oyster is moored to the seabed with its "back" to the waves, which then push the upper portion back and forth. That movement pumps water to the shore, where the pressure generates electricity. The Oyster is durable, but can't be placed in deep water.
OpenHydro -- No fancy name; OpenHydro calls its device what it is, an Open-Centre Turbine. Like a wind turbine, this is a simple device that turns as pressure is applied; the difference is that what's pushing is sea water, not air. The difference between OpenHydro and other water turbine makers is that there's a hole in the center, leaving fish and other sea critters free to pass through.
Pelamis Wave Power -- Medieval sailors were terrified of giant sea serpents; Pelamis wants to use them to generate electricity. The Pelamis Wave Energy Converter is a 180 meter long hinged tube that looks like a giant snake. It floats partially submerged. As waves cause the machine to writhe, internal pistons drive fluid through generators, generating electricity. The PWEC has been tested off Scotland and Portugal.
All 10 ideas seem good -- at least to me, but I don't have the right engineering background. The trouble is, very few people do. So chances are good that the United Kingdom government has funded at least a few duds. It's not inconceivable that a large majority of the technologies just won't perform well enough.
But if the UK doesn't do it, who will? The rest of us should count ourselves lucky that the island country is willing to shoulder the risk. Hopefully the product will be a proven wave technology that the rest of the world can use.