* GE to build 12 MW, 260 metre high offshore turbines
* Aims to deliver first jumbo turbines in 2021
* Current biggest turbines have 187 metre tip height
By Geert De Clercq
PARIS, March 1 (Reuters) - General Electric plans to invest more than $400 million over the next three to five years to develop the world's biggest offshore wind turbine, which will have a capacity of 12 megawatts and stand 260 metres (853 feet) tall.
With 107-metre blades, longer than a soccer field, the Haliade-X turbine will produce enough power for up to 16,000 households, GE said in a statement.
"We want to lead in the technologies that are driving the global energy transition," CEO John Flannery said.
GE Renewable Energy will develop and manufacture the new turbine largely in France and aims to supply its first nacelle, - or power generating unit - for demonstration in 2019 and ship the first turbines in 2021.
The firm will invest close to $100 million in a new blade manufacturing plant in Cherbourg, western France, which will open in 2018. It will also invest close to $60 million over the next five years to modernise its Saint-Nazaire factory, where the nacelles for the Haliade-X will be built.
GE, already a major global player in onshore wind, entered the offshore wind turbine market through its takeover of France's Alstom in 2015.
GE said the new turbine - which will have a direct-drive power generator rather than a gearbox - will be 30 percent bigger than its nearest competitors.
In June 2017, MHI Vestas, a joint venture between Vestas and Mitsubishi Heavy Industries, launched a 9.5 MW offshore turbine, currently the world's most powerful wind turbine.
Standing 187 metres tall and with 80-metre blades, it is an upgrade of MHI Vestas' 8 MW V164 turbine, which is already in operation at the Burbo Bank Extension and Blyth offshore wind farms in Britain.
MHI Vestas has also been named preferred supplier for Britain's Triton Knoll and Moray East offshore wind farms for a total of 190 of the 9.5 MW turbines.
An MHI Vestas spokesman declined to comment on future turbine development.
The size of offshore wind turbines - which unlike onshore turbines is not limited by overland truck transport - has grown rapidly in recent years as bigger turbines capture more wind and reduce maintenance costs and capital spending.
Onshore wind turbines in Europe have average capacities of about 2.7 megawatt, less than half the 6 MW average capacity of offshore turbines, according to trade group Wind Europe.
1 euro = $1.2188 Reporting by Geert De Clercq Editing by Mark Potter