(Adds detail on project, potential of floating offshore)
PARIS, Nov 16 (Reuters) - Europe's second-ever floating windfarm will be built off the coast of Portugal under plans set out on Monday by a group of energy utilities and engineering companies.
Floating offshore windfarms hold huge potential as the technology opens up large parts of the oceans, which would otherwise be too deep for traditional structures that can only be built in seas with maximum depths of about 50 metres.
French gas and power group Engie, Portugal's EDP Renewables, Japan's Mitsubishi Corp and Chiyoda Corp, along with Spanish energy group Repsol , are teaming up to build the windfarm, which will comprise three or four turbines.
The 25 megawatt (MW) facility is planned to be operational in 2018.
The project will be the second floating offshore windfarm pilot in Europe, after Norway's Statoil said this month it would invest about $236 million in a 30 MW, five-turbine floating windfarm off Scotland.
Engie said the aim of its project is to further demonstrate the economic potential and reliability of the floating offshore technology. It gave no financial details of the operation.
EDPR has already tested a semi-submersible wind generator carrying a 2 megawatt Vestas turbine and which has produced more than 16 gigawatt-hours over almost four years of operation, having withstood extreme weather conditions. (Reporting by Geert De Clercq; Editing by David Goodman and David Holmes)