Controversial GE wind turbine patent set to expire

UNITED STATES: After 20 years, GE’s landmark variable-speed patent quietly expires in the US on February 1, 2011.

The GEvMHI patent row has centred around MHI's 2.4MW turbine
The patent –number 5,083,039 -- has been at the heart of some of wind power’s largest intellectual property fights, most recently between GE and Mitsubishi Heavy Industries (MHI).

The expiration of ‘039, as it is commonly known, is already having an impact.

It was behind a recent federal court decision to dismiss part of GE’s appeal of the January 2010 decision by the US International Trade Commission (ITC) favouring MHI.

GE had alleged that MHI’s 2.4MW turbine violates ‘039 and two other patents and had unsuccessfully asked the ITC to ban imports of the Japanese turbine.

GE has also sued MHI in a Texas court over the same three patents, seeking damages and an injunction. After February 1, GE will only be able to seek past damages -- and it cannot seek an injunction -- for any ‘039 violation.

In a $1 billion anti-trust suit, Mitsubishi has accused GE of trying to monopolise the variable-speed wind turbine market in the US.

"The '039 patent was a fairly broad patent, yet its validity had been upheld in prior litigation," notes Larry Kass, a patent lawyer with Milbank who is following the case.  "It seems it may have been one of the stronger patents in GE's portfolio and its expiration may somewhat embolden MHI and [other GE] competitors."

Originally owned by now-defunct US Windpower, ‘039 has been among a suite of GE patents licensed by at least 10 wind companies.

The fight over the intellectual property traces its roots to 1995, when Kenetech Windpower—then owner of the ‘039—sued German company Enercon for alleged patent infringement. The dispute led to the ITC banning Enercon turbines from the US.

Variable-speed technology, which is standard for modern wind turbines, allows turbines to maximise energy capture.