Offshore wind turbines are placed to take advantage of strong, steady coastal winds. Their placement is in one way ideal – dependable energy, and lots of it – but it’s also not exactly easy to build a turbine tower in several feet of moving water. The current standard solution is to build big solid platforms that “trick” the turbine into thinking it’s still on land, but it’s not a perfect solution.
Floating Wind Turbines?
Enter Clear Path Energy, the collaborative effort between six to eight engineers. Clear Path Energy’s plan is to fill the gaps in offshore turbine technology, according to founder Geoff Sharples (previously of both Clipper Windpower and Google). The company hopes to build turbines to function in water depths of 35-100 meters — much too deep for current platform-based technology.
The Clear Path turbine is designed to have an integrated design from the single articulated joint at the ocean floor to the tiltable turbines at the top. A rigid truss leads from the joint to the buoyancy element, which is below the surface of the water, to prevent the turbine from simply tipping over. The tower can then lean at angles up to 30 degrees without actually falling over. Sharples explained that:
“[The turbine is] a bit like a flexible reed that bends rather than breaks. But under normal operation conditions it’s stiff and stable enough that it keeps the rotor oriented such that it’s capturing maximum wind.”
Developing The Technology
Clear Path Energy is currently funded by a three-year $500,000 grant from the U.S. Department of Energy (DOE), which was awarded last fall. Clear Path will be able to complete its conceptual design and test it against computer wave models with the grant, but without further sponsorship or partnership, the design won’t go beyond the paper stage.
Sharples says that, while there are many potential benefits of wind power generation at depths of 35-100 meters, there’s very little technological development that can take advantage of them.
“Now, there’s sort of a Catch-22, where there’s no [proven] technology, so there’s few projects and that’s sort of a cycle in the US.”
Just Keep Going
Still, Clear Path Energy is pushing ahead. In addition to the innovative tower base, the company also needs to have a light and robust generator. It’s designing a direct-drive ring generator, which has a higher flux cutting speed (needs fewer magnets and therefore less weight). According to Sharples, the real difficulty is in controlling the 5-10mm gap between the magnets and copper coils, but the generator will be more robust once that’s accomplished.
Even the turbines aren’t standard — instead of the usual three-bladed design, the Clear Path turbines may use two blades. The blades are wider, compared to three-bladed models, which allows for a larger I-beam inside the blade, more stability, and a larger diameter. The traditionally perceived negatives of two-bladed models (they’re louder and not as pretty) matter less when the machines are way off-shore and out of sight, according to Sharples.
Clear Path also believes that its turbine will be capable of producing energy for 25% less than current offshore wind prices — one more compelling argument for the new technology, or is it still too risky? You tell me, in the comments below.
Source: Recharge News | Image: Wikimedia Commons
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