By Keith Johnson
The Department of the Interior’s new report on offshore energy potential in the U.S. makes much ado about little new.
Part of the Obama administration’s push to revise offshore energy development, the new report (available so far only in summary form) says that the U.S. continental shelf has loads of energy potential—both in oil and gas and in renewable energy. The headline finding in the report says that offshore wind farms could provide 20% of electricity for coastal states, which would mean 16% of U.S. electricity.
But just as the report’s look at offshore oil and gas resources is plagued by “information gaps”—most seismic surveys are 25 years old, making them all but useless for planning oil and gas leases—its rosy appraisal of U.S. offshore wind potential doesn’t take into account all the economic challenges.
There’s a simple reason that offshore wind still makes up less than 1% of global wind installations: The greater cost of offshore wind outweighs the benefits of stronger and steadier ocean breezes.
The economics of offshore wind are different than in the still fast-growing onshore wind sector, where it all boils down to how much the wind turbine costs. Offshore, turbines only make up one-third of the project cost, says the U.S. National Renewable Energy Laboratory. About 25% of the cost comes from the platform to hold the turbine up, 24% from increased maintenance costs, and fully 15% from building new undersea transmission lines.
Which means that building cheaper platforms is a huge priority if offshore wind is to be economically viable. Given that the oil and gas industry has decades of experience sinking big, expensive pieces of equipment into the ocean floor or building floating production platforms, hopes abound that Big Oil can come to Big Wind’s rescue. On paper at least, a union between the oil and the wind industries could spur the development of 50 gigawatts of offshore wind power by 2025 (still a far cry from the Interior Department’s latest projection.)
But that won’t happen anytime soon, warns the NREL: “The offshore oil and gas industry has proven that the technical challenges can be overcome but the economics of implementing this industry’s solution would prohibit any deployment of machines in a competitive wind energy market.”
One possible solution? Aim higher—or deeper, as the case may be. Since the big cost hurdle is sinking platforms into relatively shallow water, pushing wind farms even farther out into the ocean, where breezes are stronger, might be the answer. In deep water, turbines would need floating platforms.
There are still all kinds of problems getting turbines to behave on pitching, unsteady floating platforms. But if those engineering challenges are overcome, the NREL says, “As the technology is advanced into deeper water, floating wind turbine platforms may be the most economical means for deploying offshore wind turbines at some sites.”