A decision by the High Court of Justice in the UK has handed Enercon a blow in the enforcement of their patent related to power ramp down after the 'traditional' cut out wind speed (EP0847496). Enercon sued Germany’s Siemens AG, Dong Energy A/S and A2Sea A/S for patent infringement, claiming that those companies respectively used, purchased and installed wind turbines comprising the Enercon patented technology.
Enercon first filed their patent in 1995 in Germany and has been commercially offering their ‘Storm Control’ technology on their own turbines for many years since. The above image representing the power output control strategy is taken from the Enercon patent.
In invalidating the Enercon patent, the UK court seems to have taken an interesting interpretation of a paper from EA Bossanyi published in 1982 which dealt with an evaluation of performance on the Boeing built MOD-2 wind turbine which was contracted by NASA and erected in 1980. Essentially, the Bossanyi paper contemplates a method for power ramp-down specially adapted to the variable speed, constant frequency (VSCF) MOD-2 wind turbine. Siemens relied upon expert testimony in arguing that this approach could be applied to variable speed, variable pitch (VSVP) machines being developed around the time of the Enercon patent filing. The UK court agreed.
Siemens also referenced a 1980 patent filing by Toshiba Corp in their attempt to invalidate the Enercon patent. The Toshiba patent describes technology which ramps down after the ‘conventional’ cut-out wind speed, but does not ramp all the way down to null output power, instead cutting out in a full-speed, partial-load condition. Nevertheless, the UK court did not favor the Siemens interpretation of the Toshiba patent by disagreeing that it teaches what Enercon claimed in their own very similar patent.
Interestingly, Danish wind turbine maker Vestas Wind Systems A/S had previously filed an opposition against the European version of the Enercon patent in a time-frame that would have allowed them to present new and potentially invalidating prior art. However, their opposition was rejected in November 2002 without citing either the Toshiba patent or the Bossanyi paper.
Nevertheless, a new opposition period against the Enercon patent filing was made possible as of January 2015 by the European Patent Office (EPO) based upon an amendment to the Enercon patent triggered by the UK court matter. The prior art references and precedent set in the UK will likely influence a decision by the EPO on the validity of the Enercon patent.
However, invalidity of the European patent is not for certain and Enercon still has the opportunity to appeal the UK ruling. The EPO does not have to accept the same conclusion as the UK court, so it will be very noteworthy if the EPO takes the same approach regarding the Bossanyi reference in their review of the Enercon patent.
Since Enercon is likely to appeal the UK ruling, the Siemens matter is far from over yet.
This European patent filing from Enercon serves as the parent to both the UK as well as the Spanish patent which is the subject of the ongoing litigation with Spanish turbine manufacturer Gamesa. The precedent set in the UK is likely to have repercussions on the litigation in Spain if the UK court position on invalidity holds.
An invalidation of the European patent would likely negate the damage award against Gamesa in Spain, but there is still potentially room for Enercon to argue their position here, so the outcome is not guaranteed for anyone involved either.
In the meantime, Gamesa should at least be able to leverage off the non-infringement arguments in their appeal in the Spanish court.
The UK court potentially establishes another interesting precedent here, because there are certainly other patents held by companies in the wind industry which attempt to deal with component loading and fatigue which could also potentially be argued as obvious in light of the UK court’s interpretation of the technology developed for VSCF being applicable to VSVP based turbines.
The UK court judge refers to adjustment of the torque and pitch control “knobs” as a means to control generator rotor rpm as an obvious method in light of the Bossanyi paper, but also acknowledges other methods of implementing such technology.
"…it required no inventive activity at all for a skilled person given Bossanyi in 1995 to think seriously about how to implement the power ramp down proposal in VSVP turbines. They would consider how to put that into practice and, in terms of controls, it was obvious to think about “turning” the electric torque “knob” and the pitch control “knob”. Reducing rotor speed as the wind speed increased as a way of reducing power accordingly is not the only way of putting Bossanyi into practice but it is an obvious approach. Reducing the speed this way has an obvious advantage in terms of loading and fatigue."
Over the past 10 years we have seen Enercon attempt to enforce patents on frequency and voltage regulation against Vestas unsuccessfully, with the result being an invalidation of those patents in Ireland and the UK. We have also seen Japan’s Mitsubishi Heavy Industries (MHI) successfully challenge the validity of the General Electric (GE) zero voltage ride-through patent in the US leading to an overturning of the USD-169-million judgement and a settlement of their other ongoing litigation matters.
The past history of the wind industry’s capitulation to licenses is likely at an end as companies arm themselves with information to defend against the onslaught of IP challenges they face. This new level of intelligence gained as well as a better understanding of the commercial implications of IP infringement risks are providing companies with the opportunity to invalidate competitor patents with greater rigor and frequency than ever before in the industry’s history.
Nevertheless, the implications of all these proceedings introduces some potentially substantial commercial risks into the project development process. Now that companies are willing to target the turbine OEMs, project developers and even the EPC contractors for patent infringement liability, the proactive companies are already arming themselves with information to ensure they can proceed smoothly.
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