Wave power: worth another look. And another, and another…

Much like nuclear fusion, wave power always seems to be at least ten years away.

The basic idea of using ocean waves to produce electricity may be simple, but the execution isn’t. The sea has a tendency to thrash the devices we stick in it, including tethered buoys that generate electricity as they bob up and down.

But a study released Thursday by the U.S. Department of Energy suggests wave power remains a dream worth pursuing. Especially in California.

Wave power devices stationed along California’s long coastline could generate up to 166 terawatt hours of electricity per year, according to the study, if those devices were placed in the water above the outer continental shelf. Wave power buoys would generate a little less, about 129 terawatt hours, if stationed above the inner continental shelf, in waters no more than 50 meters deep.

For comparison, the United States as a whole uses 4,000 terawatt hours of electricity each year, according to the Energy Department. The California Independent System Operator, which manages the electricity grid for 80 percent of California, says its territory uses about 225 terawatt hours per year.

“The takeaway message here is, it is a resource worth considering and worth doing more work on,” said Hoyt Battey, with the Energy Department’s water power program. “For the West Coast in particular — for those states — it could be a significant contribution.”

Tidal power too could benefit the state, although not to the same degree.

A related study released by the Energy Department on Thursday looked at the energy-generating potential of harnessing ocean tides at key “hotspots” across the United States, including the Bay Area’s Golden Gate. Using underwater turbines to tap the Gate’s strong tidal currents was a pet project of former Mayor Gavin Newsom. It went nowhere.

The Energy Department estimates that Golden Gate tides could generate a maximum of 178 megawatts of energy. A megawatt is a snapshot figure, roughly equal to the amount of electricity used by 750 typical homes at any given moment.

While it isn’t trivial, 178 megawatts is far less electricity than many of the large solar power plants under construction in California will be able to generate.  It also pales in comparison to the 18,239 megawatts of tidal power that Alaska’s Cook Inlet could produce, according to the Energy Department study.

“What we have heard from developers and experts who’ve looked at the Golden Gate is it’s somewhat marginal — on the fence — in terms of development,” Battey said. “That’s not to say it couldn’t be developed at some point.”