The great renewable energy myth is that it's more expensive than obsolete sources of power. While that's arguably true for solar -- although less so all the time -- it's definitely not the case for wind. And, as it turns out, it's not the case for wave power, either. Built in the right locations, wave power generation can be as inexpensive as wind -- that is, competitive with more traditional power technologies (and, I would argue, even cheaper when externalities are added in). This comes from EPRI, the Electric Power Research Institute, following a multi-year study of the economics of wave energy.
Conceptual designs for 300,000 megawatt-hour (MWh) plants (nominally 120 MW plants operating at 40% capacity factor) were performed for five sites: Waimanalo Beach, Oahu, Hawaii; Old Orchard Beach, Cumberland County, Maine; WellFleet, Cape Cod, Massachusetts; Gardiner, Douglas County, Oregon; and Ocean Beach, San Francisco County, California.The study determined that wave energy conversion may be economically feasible within the territorial waters of the United States as soon as investments are made to enable wave technology to reach a cumulative production volume of 10,000 - 20,000 MW. (Land-based wind turbines, in comparison, generate 40,000 MW.) [...]
There are several compelling arguments for investing in offshore wave energy technology. First, with proper siting, conversion of ocean wave energy to electricity is believed to be one of the most environmentally benign ways to generate electricity. Second, offshore wave energy offers a way to minimize the 'Not in my backyard' (NIMBY) issues that plague many energy infrastructure projects. Wave energy conversion devices have a very low profile and are located far enough away from the shore that they are generally not visible. Third, wave energy is more predictable than solar and wind energy, offering a better possibility of being dispatchable by an electrical grid systems operator and possibly earning a capacity payment.
The final report can be downloaded here (PDF); the individual reports for the five location studies are also available. The final report gives a good breakdown of how competing wave energy technologies work, and how they compare to other renewable sources. Ocean power has outstanding potential: the report claims that "the total U.S. available incident wave energy flux is about 2,300 TWh/yr. The DOE Energy Information Agency (EIA) estimates 2003 hydroelectric generation to be about 270 TWh, which is a little more than a tenth of the yearly offshore wave energy flux into the U.S."
While wind and solar tend to get a lot of attention, ocean power is quietly becoming a winning pathway to renewable energy. The first ocean power system connected to the grid opened in Orkney, Scotland, in August; it's a test system producing 750kW. Orkney will eventually be home to 40 such systems in a "wave farm," producing 30MW of power. Orkney won't be alone for long: a program is underway to test wave power systems off the coast of Spain, a 254 megawatt tidal power system (a similar technology) is underway in South Korea, and a smaller tidal power system is planned for New York's East River.
[EPRI is one of those organizations which you probably haven't heard of but is actually rather influential. The Electric Power Research Institute is a think tank of sorts, largely funded by work for power companies but nonetheless independent of them. (Disclosure: I have worked on several scenario projects for EPRI and EPRI subsidiary organizations over the past decade.) They aren't a green or sustainability-focused group, but they've been pushing for greater emphasis on renewables and concern about climate disruption for as long as I've known them.]
Though its not realestate in the the most conventional sense, the near-shore waters where one would have to deploy wave power generation systems are still some very valuable acres of this earth's surface. Recreational use, fishing, wildlife habitat...all the other uses of these waters would be disrupted by a flotilla of wave energy capturing devices of any design...the amount of energy they can intercept form waves is proportional to the area they take up and decreases the more you submerge them. These systems would have to have a far greater negative impact on human and animal life than smaller foot print of wind powered towers, ugly though those towers might be. The economics may be favorable but I don't see an honest assessment of the total cost to the environment or even just to the humans that will be affected.