GE in wind patent battle with Mitsubishi

The battle between two of the world’s largest wind turbine manufacturers heated up yesterday, when engineering General Electric (GE) filed a lawsuit against Mitsubishi Heavy Industries (MHI) accusing its arch rival of infringing two patents covering technologies used in variable speed wind turbines.

The suit, filed in Dallas, Texas, alleges Mitsubishi’s wind turbines infringe on GE patents for systems that help wind turbines remain connected to the grid when voltage drops and provide a frame that supports the weight of a turbine’s rotor, gearbox and drive shaft.

GE cited 2.4MW Mitsubishi wind turbines installed at the Goat Mountain wind farm in San Angelo, Texas as evidence of the alleged infringements.

One of the patents is related to the base frame supporting the weight of the rotor and the other covers a way to keep the wind turbine connected to the electricity grid even when the voltage drops.

“GE has 148 issued U.S. patents related to wind energy,” Dan Nelson, a spokesman for the Fairfield, Connecticut-based company, said in a statement. Mitsubishi “has substantially less. We believe that there are multiple areas where MHI’s 2.4-megawatt wind turbines infringe on GE’s existing patents.” GE sought to block imports of wind turbines made by Mitsubishi Heavy.

The dispute is part of a larger legal effort by GE against Mitsubishi Heavy, which is seeking a bigger foothold in the U.S. market, now dominated by GE and Denmark’s Vestas Wind Systems A/S.

In 2009, wind farms almost matched the additions of natural-gas fueled plants for a second year, together accounting for 80 percent of all new generating capacity in the U.S., the American Wind Energy Association said.

GE, the largest wind power supplier to the U.S., built 2,633 wind turbines last year, down from more than 3,323 wind turbines in 2008. Wind speeds change all the time, so the wind turbines must be built to provide a constant source of power.

GE, in a lawsuit filed in September against Mitsubishi Heavy, is seeking cash compensation for past infringement of the five patents in the ITC case. That case was put on hold until the ITC completed its investigation.

The new case is General Electric CO. v. Mitsubishi Heavy Industries Ltd., 10-cv-00276, U.S. District Court, Northern District of Texas (Dallas).

The ITC case is In the Matter of Certain Variable Speed Wind Turbines and Components Thereof, 337-641, U.S. International Trade Commission (Washington). The previous civil case is General Electric Co. v. Mitsubishi Heavy Industries Ltd., 09cv229, U.S. District Court, Southern District of Texas (Corpus Christi).