The concept of harvesting the ocean as an energy source is nothing new, but in practice it's rarely utilized. That's beginning to change, though. This week, the first major underwater turbine was installed in Northern Ireland's Strangford Narrows—a body of water known for its fierce currents. SeaGen's twin blades measure 52 feet wide, and instead of intermittent winds, this green electricity generator will rely on the ever-changing tide to produce power for around 1,000 homes. Built by Marine Current Turbines, it will be operational this summer.

A new player has stepped into the middle of the Cape Cod offshore wind farm debate, proposing a technological solution that may finally bring the long-running fight to an end. Blue H, a subsidiary of a Dutch company, has proposed the installation of 120 floating wind turbines that would be anchored far from shore and, more importantly, out of sight. Cape Wind, the company that first proposed an offshore wind farm in the area, wants to use standard turbines. But those with beachfront property in the area don’t want their lovely views of the seascape ruined by the spinning blades.

One common complaint about wind turbines is that they blemish the scenic countrysides and coastlines where they perch. Now an architect in London has an attractive solution. The “wind dam,” a giant swath of fabric connected to a turbine, looks more like a Christo art installation than a power generator.

Wind power is the world’s fastest-growing energy source. Existing capacity worldwide is approaching 50,000 megawatts—roughly equivalent to that of 50 nuclear power plants. But there are problems with this seemingly benign wellspring of pollution-free electricity. Aside from being noisy, the whirling turbines interfere with television reception and are generally considered terrestrial eyesores rendered useless when the wind stops.