Energy is an essential commodity for every sophisticated society. The UK has revelled in the "energy windfall" of North Sea oil for four decades and in coal combustion for over two centuries. Climate responsibility is one reason why we must stop burning oil and coal rather suddenly but it is not the main one. The UK has an extraordinary resource in the form of offshore wind. We could meet all of our present demands at least twice over and still export some. We are importing large amounts of energy at present (including coal and oil) and we would do well to stop doing so - not least in view of Brexit. Historically, offshore wind has been thought to be expensive but recent estimates are now pointing to costs between €30/MWh and €40/MWh for offshore wind by 2025! It is useful to compare this with the Hinkley Point C nuclear power station for which we are committed to paying £92.50/MWh for every single MWh that comes out of the station for 35 years - and even that is index-linked back to 2012.

 Windpower opponents will point out that the wind does not blow all the time and of course they are right. The conventional view of a wind turbine is that it is a device that generates electricity when the wind blows. It does not have to be so. A wind turbine could be a device that collects energy when the wind blows and dispatches electricity when that is required. If you could equip a wind turbine with energy storage equivalent to about 100hours of rated output power, that system would as good as a coal/oil/gas fired power station for all practical purposes in terms of its ability to deliver power on demand. Conceptually this is simple. You could achieve it with batteries but the batteries would cost about 50 times as much as the wind turbines and €40/MWh would turn into an unaffordable €2000/MWh. Alternatively you could do some really slick mechanical engineering ...

Further reading:

Two papers mentioned in the presentation:

https://journals.sagepub.com/doi/abs/10.1260/0309-524x.39.2.149

https://www.sciencedirect.com/science/article/pii/S0301421515300458

This, below, is a copy of a paper specifically about Body-Yawing Semi-Submersibles: 

https://www.tetrafloat.com/FileStore/Body_Yawing_SemiSubs_Paper.docx

This next paper summarised early-days thoughts concerning how to integrate storage with wind. This one won the Arthur Charles main prize for best paper from the IMechE Power Industries division.

https://journals.sagepub.com/doi/pdf/10.1243/09576509JPE973

There is a lot of relevant information available from the one-day conference on March 23rd: www.era.ac.uk/Medium-Duration-Energy-Storage