While that legal battle spans multiple venues, encompasses several different patents, and includes many patent and antitrust issues, the heart of the dispute is the allegation that Mitsubishi’s 2.4 MW turbine infringes GE’s patented technologies.
More particularly, GE has asserted infringement of its patented variable speed technology, particularly as claimed in U.S. Patent No. 5,083,039, a seminal patent relating to methods for enabling turbines to efficiently feed power from wind of variable speeds into the utility grid.
Another key patent asserted by GE is U.S. Patent No. 7,321,221, relating to low voltage ride through technology for stabilizing the supply voltage to a wind turbine after voltage drops without jeopardizing the electrical components of the turbine.
In its antitrust case against GE, Mitsubishi has alleged that GE’s patent infringement claims are baseless and are intended to intimidate Mitsubishi’s potential customers.
According to Mitsubishi, its $2 billion in annual U.S. sales of variable speed wind turbines has dropped to zero since initiation of the first patent infringement suit in early 2008.
In a glimmer of good news for Mitsubishi, Windpower Monthly recently reported that at least one customer is undeterred by the cloud over Mitsubishi’s 2.4 MW turbine.
According to the article, the utility Duke Energy has ordered 202 MW of the controversial turbines for its Los Vientos II wind project in Texas. The article says it is the first order since the advent of the patent dispute with GE.
It will be interesting to see if this vote of confidence by Duke clears away the cloud over Mitsubishi’s 2.4 MW turbine and leads to more orders.
Eric Lane is a patent attorney at Luce, Forward, Hamilton & Scripps in San Diego and the author of Green Patent Blog. Mr. Lane can be reached at firstname.lastname@example.org.