The Search for Energy Takes a Turn Underwater

The fearsome tides that sweep out from the easternmost shores of the United States have for more than 80 years teased engineers and presidents like Franklin D. Roosevelt, who have dreamed of harnessing their force to make electricity.

Soon, a device that looks a bit like an eggbeater turned sideways will be lowered into the water here to catch the energy of the rushing water, spinning a generator that, come September, is scheduled to begin sending power to the grid. It is an experimental, expensive and promising project, fueled by the knowledge -- shared by Roosevelt, who spent summers across the bay on Campobello Island, and modern engineers -- that the tides here are both powerful and predictable.