The constantly churning oceans that cover most of the Earth offer an inexhaustible source of clean energy. The amount of recoverable energy embedded along the continental shelf of the United States, for example, amounts to almost a third of all the electricity the country uses in one year, according to estimates from the Electric Power Research Institute,

"It's emission-free power and it's located close to where most of the population lives," said Sean O'Neill, president of the Gaithersburg, M-based Ocean Renewable Energy Coalition (OREC).

But the process of harnessing all of that energy, still in its infancy, isn't an easy one. "At this stage, putting equipment in the sea and getting it to work reliably, consistently, during severe storms, is