ELLSWORTH, Maine — The waves and tidal currents off the coast of Maine represent a vast, largely untapped energy resource capable of producing more than 15 trillion watts of electricity per year, according to two federal reports.

Maine’s turbulent oceans and surging tidal rivers have long been regarded as enormous pools of renewable energy. Two recent reports from the U.S. Department of Energy attempt to attach a figure to that potential in Maine and across the country as both policymakers and energy developers seek new, more environmentally friendly ways to meet the nation’s energy demands.

The two separate assessments of potential wave energy and tidal energy sources in Maine determined that if developed to their maximum potential those sources could contribute more than 15 terawatt-hours of electricity annually. Nationwide, the total theoretical generation capacity was more than 1,400 terawatt-hours per year, which is roughly one-third of the nation’s annual electricity use.

Federal officials acknowledged that those are theoretical figures and that not all the potential resources could realistically be tapped. But they said the reports showed the potential for expanding the nation’s use of hydropower of all types to generate electricity — and that Maine could play a major role in that expansion.

“Maine’s wave and tidal current resources offer real opportunities to generate renewable energy using water power technologies in the future,” Energy Secretary Steven Chu said in a statement. “Together with new advances and innovations in water power technologies, these resource assessments can help to further develop the country’s significant ocean energy resources, create new industries and new jobs in America, and secure U.S. leadership in an emerging global market.”

For tidal energy, Maine had the third-highest potential behind Alaska and Washington in terms of the total theoretical generation capacity and the number of tidal “hot spots.”

Topping Maine’s list of potential hot spots were areas of Down East Maine, specifically the Western Passage near Eastport, Cobscook Bay, Lubec Channel and Grand Manan Channel. But the Kennebec River, Knubble Bay and Hockomock Bay near Woolwich as well as the Piscataqua River on the Maine/New Hampshire border also were highly rated.

Residents of far Down East Maine soon may see some of that potential energy turn into actual electricity.

Later this spring, Ocean Renewable Power Co. plans to install underwater turbines similar to giant paddle wheels in the waters near Eastport and Lubec to capture the world’s largest tidal range — the vertical distance between high and low tides — flowing from the Bay of Fundy. That range is sometimes as much as 50 feet in the area.

John Ferland, vice president of development at Ocean Renewable Power Co., said the Federal Energy Regulatory Commission has recommended approval of the project although the agency’s environmental assessment for the project remains open to public comment. Ferland said Friday that Ocean Renewable hopes to be connected to the grid and generating electricity by June or July.

“The tidal energy business is all about location and you need to go where the resources are best,” Ferland said. “In our opinion, the best resources in the world are in the Bay of Fundy and Cook Inlet in Alaska. We are operating in both places.”

The Maine projects will be relatively small — probably generating about 60 kilowatts. But Ferland said this initial project should lead to bigger projects and additional jobs in an area well suited to develop tidal power technology, given the region’s fishing and maritime history.

“This is a modest project that gets us started and one that we can build on,” he said.

Maine also is regarded as a promising location for offshore wind projects and researchers from the University of Maine and private companies are working to design turbines that can be deployed in deep waters.

But development of renewable energy projects — especially those using new technology — requires substantial investment. And Dylan Voorhees, the clean energy project director for the Natural Resources Council of Maine, said he is hearing from potential developers that they are uneasy about investing in Maine because of the political climate.

The Natural Resources Council of Maine and other groups have publicly clashed with the LePage administration over several issues involving renewable energy. LePage has made lowering Maine’s energy costs a top priority and has suggested that the referendum campaign to mandate that utilities increase the percentage of power from renewable sources would drive up costs. The administration also has targeted the current renewable energy mandate, arguing that consumers who want “green power” should be given the choice to buy it at a higher cost.

Voorhees suggested that developers may be uncomfortable with the messages they are getting from the LePage administration.

“We have huge opportunities,” Voorhees said. “But the question is are businesses and developers going to put their money here?”

Kenneth Fletcher, head of the governor’s Office of Energy Independence and Security, could not be reached for comment on Friday on the federal reports.