Power from the oceans: Blue energy

Several kilometres off the coast near Perth in Western Australia, hidden beneath the waves and out of sight of watchful boaters, three giant buoys will soon begin producing electricity as they bob to the rhythm of the Indian Ocean. At 11 metres wide and 5 metres tall, the squat orange floats look a bit like giant pumpkins. As waves pass by, the tethered buoys will drive hydraulic pumps on the sea bottom, converting the motion of the ocean into 720 kilowatts of electricity to power a nearby naval base.

Carnegie Wave Energy of North Fremantle, Australia, plans to have the system — the latest attempt at harvesting power from the sea — up and running by June. The pilot project will generate a lot of press, but veterans of the marine-energy field will watch warily to see how it fares. This industry has taken a slow road: none of the myriad devices designed thus far has proved its worth in the highly competitive energy market, and few have survived prolonged exposure to the harsh conditions in the sea. Despite an overall investment of around US$735 million over the past decade by a dozen leading companies, marine power from tide and waves has yet to take off. In fact, it remains the most expensive form of power on Earth.