Floating, Over the Horizon, Wind Energy

June 14, 2008 – Vol.13 No.12

FLOATING, OVER THE HORIZON, WIND ENERGY.

If the United States is to tap its significant offshore wind resources for electric energy it’s likely that it will have to go far offshore, over the horizon and out of sight of land, to install wind turbines.

The nation is wealthy. Its ocean view landowners are the wealthiest. They’ll spend considerable sums to keep turbines out of their vistas. The wealthy know the power of the courts. They know the value of lawyers. They’ll keep offshore turbines at bay. They may be concerned about oceans rising from global warming and want clean energy, they just don’t want it in view, in their front yards.

But far offshore, where wind resources are best and bird flyways aren’t as likely, wind turbines could float. Deep water offshore oil platforms do. Why not wind turbines? In a decade or so it may just be a matter of economics. As prices for conventional energy rise, the price for non-conventional energy will become more competitive and appealing, even if it is seemingly expensive wind energy from the high seas.

The significant expense for far offshore wind might not be in the floating turbines themselves but in the miles of high voltage power cables needed to connect them to shore. Offshore oil and gas facilities use undersea pipes to bring gas and liquids to ocean front terminals. Laying cables should be easier, less expensive. Can electricity generated from over-the-horizon wind make enough money to justify the cost of the cables? Likely. Especially if the cost of oil and gas rise further.

There are other costs associated with floating wind turbines that need to be considered as well. Maintenance will be high. Working in the high seas won’t be easy.

The loss rate of turbines to storms might be a factor as well. Will far offshore turbines be able to survive hurricanes? Of the 2900 oil rigs and drilling platforms in the path of Hurricanes Katrina and Rita in 2005, only 109 were lost. Aerodynamic wind turbines might have an even better survival rate.

There’s an additional economic factor that will determine whether offshore wind will be feasible. Can offshore wind compete with onshore wind planted far from the heavily populated (and heavily energy consuming) coastlines? The nation’s midsection – largely the expanse between the western mountains and Mississippi – is prime territory for wind development. (And that huge area IS being developed.) Including line losses from electrical resistance in the cables will it be cheaper to send power to populated areas over land hundreds of miles away than take it from relatively near sources on the ocean?

Beginning in 2009 the answers to the technical and economic feasibility of floating offshore wind turbines will begin to be answered as Siemens and StatoilHydro anchor the world’s first floating wind turbine in waters off the coast of Norway.

In the Hywind project StatoilHydro will supply the buoy on which the turbine from Siemens will be mounted. The Spar-buoy – the key player in the prototype – will be made of concrete and steel with ballast tanks. Sinking 120 meters (nearly 400 feet) below the surface, its low center of gravity will keep the turbine on its tower upright. The device will be anchored to the sea bed with flexible cables. Siemens says the floating turbine could be used at depths up to 700 meters (2300 feet).

It will take two years to test and develop the Hywind turbine, but Siemens is already dreaming of a floating offshore wind farm with 200 turbines that would power a million households.

Links:

StatoilHydro
http://www.statoilhydro.com

Hywind
http://www.statoilhydro.com/en/NewsAndMedia/
News/2008/Pages/hywind_fullscale.aspx

Siemens Power Generation
http://www.powergeneration.siemens.com

--- Wide Open Spaces for Wind.

--- Price Hike for Offshore Wind? Floating Deep Water Wind Turbines Could Come to the Rescue.