Guy was speaking at a panel debate of business leaders at RenewableUK's Global Offshore Wind Conference in Manchester (21-22 June).
"We've just seen the merger of Siemens and Gamesa. I think it is definitely a concern for us that we don't want to end up with a duopoly in offshore of Siemens and MHI Vestas," he said.
"We want GE Renewable Energy to step up more. That would be great. And, ideally, there is a future for Adwen in some form or another.
"For us, competitive pressure is really critical, and that's not only in terms of the contracting side, but obviously in terms of how companies drive forward with innovation.
"Of course, the European market is limited, so how much room is there for four major suppliers? But if you just end up with two that becomes a real concern for the industry."