PORTLAND — A Maine-based tidal power company has made the cover of Popular Science.

The cover of the June issue features one of Ocean Renewable Power Co.’s underwater turbines, which uses rotating foils that spin in the same direction, regardless whether the tide is coming in or out.

Last year, the company installed one of the units in Cobscook Bay and connected it to the power grid, providing enough electricity for about 25 homes. The pilot program calls for more units to be installed off eastern Maine, providing enough power for more than 1,000 homes.

The Popular Science issue focuses on five technologies that could help the nation reach energy independence. Ocean Renewable sees an international market for its system.