Abstract :
Capricious air currents and passing clouds may thwart wind and solar power, but the tides, governed by the gravitational pull of the moon and the sun, might prove a more dependable energy source. In certain spots, the tides have already proved a good source of electricity. La Rance Tidal Power Station-a barrage on the Rance River´s estuary in Brittany, France-has converted the tides´ movements into as much as 240 megawatts of electricity since 1966. But support for new projects is less predictable: Backing has ebbed for some designs, while for others it´s just starting to flow.
