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Europe patent office rules on prior art -- Variable speed patent withdrawn but GE considers appeal

The disputed European patent on variable speed wind turbine electronics held by General Electric Power Systems has been withdrawn following a two day oral hearing at the European Patent Office (EPO) on June 16-17. "All points of the patent were withdrawn because prior art existed," says Aloys Wobben, owner of turbine manufacturer Enercon, one of ten companies that appealed the patent directly after it was granted at the end of 1998.

General Electric has the option of appealing the EPO decision. It must lodge its appeal within two months of publication of the opposition division's written decision, expected after the summer. The indication from GE Wind's Steve Zwolinski is that company strategy will be to exploit the appeals process to the bitter end to make the most of the competitive advantage the patent provides. "This is part of a long process. We have only heard the oral judgement," says Zwolinski. "When we receive the written judgement, our lawyers will be looking into it."

An appeal will be handled by the EPO's Technical Board of Appeal in a procedure that could take up to three-and-a-half years. "During that time, the patent would remain at the grant procedure stage but at the same time technically enforceable. In practice, it would be very weak," according to the EPO. If the appeal board revoked the patent "it would then be finally dead," adds the EPO.

Defence strategy

Enercon was particularly concerned about the outcome of the opposition division oral hearing appeal after GE Wind filed law suits six months ago for breach of patent against Enercon's sales agents in the UK and Canada (Windpower Monthly, May 2003). The opposition division's decision is likely to have an impact on these court cases.

As part of its defence strategy, Enercon has filed a law suit in Germany against GE over infringement of Enercon patents. Wobben declines to reveal further details of the progress of this action. His fury at being forced to spend time and money on lawyers was evident last month at the European Wind Energy Conference in Madrid. Seated close to Zwolinski on a panel of wind company bosses he bitterly decried GE's action in front of several hundred delegates, using language that left no room for misunderstanding. The outburst was met with sporadic applause.

Vestas' challenge

The existence of the GE patent has had considerable impact on wind industry technology development, limiting the use of variable speed turbines, which are described by UK consultant Andrew Garrad as "probably the technically preferred solution for most manufacturers." Garrad, boss of UK wind consultancy Garrad Hassan, is one of the most respected engineers in the business. An American version of the patent led to Enercon being banned from the US and for the past many years has required other European companies to "optimise turbines for the North American market," an oft-heard euphemism for technology adapted to steer clear of patent infringement. In America, Vestas markets a 1.8 MW adapted version of its popular 2 MW turbine.

But in a bold change of strategy, Vestas has now launched its newest and largest turbine -- a 3 MW variable speed model -- directly into the US market. It chose the occasion of the American Wind Energy Association's annual conference and exhibition, held in May in Austin, Texas, to unveil the new turbine right under GE's nose.

Vestas' boss Svend Sigaard says the 3 MW model, which uses Vestas' "Optislip" technology, "only partially" operates with variable speed revolution and does not have the same mechanical control system as the 2 MW unit. For this reason, says Sigaard, Vestas is not in danger of breaching the GE patent.

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