The departments of Energy and Interior are planning a joint effort to support offshore wind farms over the next five years, a move aimed at reducing cost and development risks and easing the regulatory constraints that have hindered construction to date, according to a statement Friday.

There’s enough potential wind power off U.S. coastlines, 2 terawatts, to almost double the nation’s total installed capacity, yet the high cost of turbines at sea have prevented development. Increasing the scale of the industry would help offshore wind become competitive in some areas by 2025, with a cost of less than $100 a megawatt-hour, according to a report issued Friday by the two agencies.

“The first offshore wind farm has now finished construction, and we have gone from zero offshore wind areas leased before this administration to 11 areas that total the size of Rhode Island,” Energy Secretary Ernest Moniz said in the statement.

The agencies have set 30 objectives over the next five years to help encourage development, building on a 2011 plan that led to an allocation of $200 million for three demonstration projects in Maine, New Jersey and Ohio, in Lake Erie.

Adding 86,000 megawatts of wind power would almost match the 96,000 megawatts of installed capacity in the U.K. It would support 160,000 jobs, reduce the amount of water consumed by U.S. power plants by 5 percent and cut greenhouse gas emissions by 1.8 percent, the Energy Department said.