On the West Coast of the United States and in Japan, it could be offshore wind power’s best hope. On the U.S. Atlantic Seaboard, some see it as the likely second generation of an industry that’s just getting going. And in Europe, where offshore wind is a significant but expensive source of energy, there’s optimism that it could offer a long-sought price breakthrough by taking advantage of cheaper installation costs and superior wind resources.

We’re talking about floating wind turbine technology, which has been suffering the ups and downs common to cutting-edge renewables, but seems to be maintaining enough momentum to make it worth watching.

Just this week Alstom, the company behind the world’s largest installed offshore wind turbine, announced a partnership with DCNS Group, a big French naval defense contractor that’s been dabbling in marine renewables. Together, they aim to place Alstom’s 6-megawatt Haliade turbine on a floating platform, instead of putting it on pillars driven into the seabed.

“By combining the technology of our Haliade offshore wind turbine with DCNS’ unique expertise in the maritime field, we are merging our respective know-hows as early as possible in the process so we can work together at developing an innovative, competitive energy solution,” Alstom Renewable Power Chairman Jérôme Pécresse said in a statement.

DCNS had for several years been part of the Windflo consortium that intended to test a 1 MW demo turbine at France’s SEM-REV center. That plan unraveled, only to be quickly replaced by a project called Floatgen, using a ring-shaped platform technology from Ideol. In July, SEM-REV said Floatgen was now fully permitted and “ready for testing.”

If and when that happens, it won’t be the first such demo project in European waters – the world’s first floating turbine test was Statoil’s Hywind in 2009 in Norway, followed by the 2012 launch of WindFloat, an Energias de Portugal project off Portugal that used technology by the Seattle-based company Principle Power.

Trimming the stubbornly high cost of offshore wind power has driven European interest in floating wind turbines, but there’s no other option off the West Coast of the United States. Beach-side turbines wouldn’t be tolerated, and the continental shelf quickly drops off to deep water.

Principle Power is the designated standard bearer for giving the technology a shot in the United States – in 2012 it received $4 million from the U.S. Department of Energy in a competition of sorts with several other advanced offshore technologies. The company’s Windfloat technology emerged a winner, and Principle is set to receive federal funding of $47 million toward a five-turbine, 30 MW project in 1,400-foot-deep water about 18 miles off Coos Bay, Oregon. The project, with a total price tag north of $200 million, aims to be in operation by 2017.

Deepwater Wind – the company behind what could be the first U.S. offshore wind farm, in Rhode Island waters – is actually developing Windfloat Pacific, using the semi-submersible platform technology that Principle pioneered off Portugal.

“It’s been performing flawlessly off Portugal for two and a half years,” said Kevin Bannister, the company’s vice president for business development Americas & Asia. Three major questions have been answered in Portugal, Bannister said. First, it was built onshore and towed out to its mooring site without issue. Second, on survivability, the turbine has withstood waves over 50 feet. Third, the tripod platform, which uses an active ballast system, can keep the mast stable enough such that a standard turbine can operate on it without loss of efficiency.

“That means that we can fully take advantage of an excellent wind resource,” Bannister said, achieving a capacity factor over 40 percent off Oregon, much higher than land-based wind power in the Pacific Northwest.

The University of Maine floating turbine project called VolturnUS, which got a small-scale device in the water last year, lost out to Principle’s Oregon project for a big DOE prize, but a nearly $4 million cooperative research agreement signed last month has given VolturnUS continued life.

Meanwhile, in Japan the Fukushima Floating Offshore Wine Farm Demonstration Project is poised to make floating wind’s biggest leap: The consortium behind that effort said in June that it will begin mounting a 7 MW turbine on a platform this December, following up on trial run of a 2 MW turbine that began last November. (A second 2 MW floating turbine demo went into service last fall in Japan, off Nagasaki.)

These different projects all use similar and familiar turbine designs, and are distinguished by their platforms. But there is one wild card: the DeepWind Project, an EU-backed effort to explore the possibilities of using a vertical-axis turbine – starting at 5 MW but possibly going up to 20 MW. The research team recently concluded its work with the wind-tunnel test of a 1 kilowatt model, and now hopes to see industry take the concept forward.