Monday 30 September 2013

EWTEC - Inore group discussion session

After the INORE workshop panel discussion, the panel joined the audience, and we broke into several discussion circles. The most interesting point that came out of the group that I joined was a discussion of a point Peter Frigaard had made in the panel session. Peter had mentioned that for wave power, the extreme loads are much greater than the operational design loads – he estimated a factor of 30. I've heard this concern voiced by several people, including Peter Fraenkel. Peter Frigaard pointed out that wind turbines shed loads by pitching their blades once they reach rated wind speed. They also have the option of yawing to reduce loads. In the break-out discussions, Prof Falcão emphasised Peter's point. He spelled out Peter's implicit suggestion: that wave power needs to have some element of adaptable geometry to reduce this gap between operational and extreme loads.

Most of the discussion session focussed on options for overcoming the barrier presented by the first prototypes being capital intensive and high risk. There was some discussion of combining offshore wind and wave power; the extreme extent of which is a platform that provides a reaction point for a wind turbine and one or more WECs. In particular, this was seen as a way for development of wave power to piggy-back on existing offshore wind farm developments. There were arguments both for and against this idea. The 'for' arguments were the cost savings due to shared infrastructure, the lower percentage of time that no power was generated, and the potential for the WECs to act as breakwaters to ease marine operations. The 'against' argument was that there was a disincentive for an existing offshore wind part to add wave to the array, as this would increase the project risk (particularly given the track record of wave power to date in terms of catastrophic failures). I offered my opinion that the additional capital required to add WECs would probably give a better return on the investment if it were spent on additional wind capacity – yet another disincentive. Enrique Vidal Sánchez suggested that once wave power was 'a valid option' on its own, that there might be some benefit in having combined wave and offshore wind parks.

Another niche market that was suggested as a developmental stepping stone was the replacement of marine diesel. I had presumed that oil platforms generated their power from incidental gas or raw crude just pumped from the ground. However, the consensus was that the oil is processed onshore and shipped back to the oil platform. So perhaps there is a niche opportunity for WECs to produce power for consumption on oil platforms? Technically, by reducing the costs incurred by the oil platform, wave power would be contributing to making oil cheaper. I imagine that the benefit for wave power would be more significant than the benefit to the oil industry – the challenge might be finding an oil company that does not see wave power as a future competitor for oil.

Another suggestion was the possibility of using decommissioned oil platforms as stable reaction points for WECs. In some countries, a power-line to shore is required as a back-up to the on-board generators. This might present an opportunity for wave power to get some beta-testing done without paying for all the infrastructure up-front.

Image credits:

Bow wake: bloggers own photo – a mosaic above a doorway, near the river in Aalborg.

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