Vestas Challenge to Invalidate GE Wind Tech Patent is Denied

  • The Patent Trial and Appeal Board denied a challenge brought by Vestas Wind Systems A/S against a General Electric patent directed to technology for connecting wind turbines to the electric grid.
  • GE and Vestas remain locked in a long-running patent battle over “Zero Voltage Ride Through” or “ZVRT” technology. Each party has brought challenges against the validity of the other party’s patents to the Patent Trial and Appeal Board, which is expected to hear those challenges over roughly the next 12 months.

The Patent Trial and Appeal Board denied a challenge brought by Vestas Wind Systems A/S in the year-long patent feud with General Electric.  The Board, an adjudicatory body within the U.S. Patent and Trademark Office, determined that the challenge brought by Vestas against GE’s U.S. Patent No. 6,921,985 was nearly identical to an earlier challenge heard by the Patent Office.  Since re-hearing similar challenges is considered an inefficient use of the limited resources of the Patent Office, the Board decided to deny the Vestas challenge.

The parties began their patent dispute in July 2017 when GE sued Vestas in federal court for allegedly infringing a pair of GE patents directed to technology for safely connecting wind turbines to the electrical grid.  Later that year, Vestas countersued, alleging that GE infringed two Vestas patents in the same technological field.  The parties then challenged the validity of each other’s patents at the Patent Trial and Appeal Board, and the federal court litigation was stayed pending the outcome of these challenges.  To date, GE has seen both of its challenges to a Vestas patent “instituted,” or accepted for trial before the Board.  In contrast, Vestas has had only one of its two challenges instituted, with a third challenge to be decided in the coming months.

For the Vestas challenge against the 985 Patent, Vestas argued that the claimed invention of the patent was obvious – and thus unpatentable – when compared against what was already known in the wind turbine industry circa 2003 (when GE filed a patent application that became the 985 Patent).  The 985 Patent is directed to technology that allows a wind turbine to stay connected to the electrical grid during a low voltage transient; GE has named this technology “Zero Voltage Ride Through” or ZVRT.

To demonstrate the state of wind turbine technology in 2003, Vestas used a requirements document made by E.ON in 2001 called the Supplemental Network Connection Rules for Wind Energy Systems.  Vestas argued that this E.ON document, when considered with additional documents and knowledge available at the time, would have rendered the claimed ZVRT technology obvious to a typical wind turbine designer.  If that was true, then the 985 Patent should not have been issued by the Patent Office and would be subject to cancellation.

GE fought back against the Vestas challenge by noting to the Board that the E.ON document had already been extensively reviewed and considered by the Patent Office during a previous challenge to the 985 Patent by another party.  The Board has rules that allow it to end any challenge that is based on “the same or substantially the same” documents and arguments that were already considered by the Patent Office.  The E.ON document was considered by the Patent Office years ago during a challenge brought by Mitsubishi Heavy Industries while Mitsubishi and GE were engaged in patent litigation.  The 985 Patent survived that earlier challenge that was based in part on the E.ON document.

In its decision issued in late October, the Board ultimately agreed with GE that the Vestas challenge to the 985 Patent was too similar to Mitsubishi’s earlier challenge.  Due to the similarity between the documents and arguments presented, the Board determined that moving forward with the Vestas challenge by instituting a trial would be a waste of Board resources.  As a result, the Board denied Vestas’s challenge to the 985 Patent.

Although denial of this challenge is a negative development for Vestas, it has another challenge against the 985 Patent that remains pending at the Board.  That second challenge was filed a few months after the recently-denied first challenge, and provides alternatives to the E.ON document as a basis for unpatentability.  A decision on whether to institute that case is expected by the end of February.