Orkney

Two new publications

I’ve had two publications appear online in the last few weeks, in the opposite order to that in which I actually did the work. They have a lot in common, using similar methods in different locations, so I thought I’d write about them together.

The most recent is my second journal article as lead author, and one that I’m quite proud of. It covers the work that I did in Japan last year, and in the months after returning, on the tidal energy resource of the Goto Islands of Nagasaki Prefecture. We produced estimates of the amount of power that could be obtained – which is mostly of interest for the people planning tidal development in that archipelago – but of more general interest are the findings about inter-channel interactions. The Goto Islands have several parallel channels that could contain turbines. ¬†When this arrangement has been studied in other places, it has usually been found that putting tidal turbines in one channel causes flow to divert into the others, and hence that to reach the full potential for power we would have to put turbines in every channel. Goto doesn’t behave like that – instead, the channels have very little effect on each other – and in the paper we looked a little into why that is. My thanks are due, of course, to my co-authors on this work, both in Scotland and Japan.

 

Plot showing the mean power produced by different numbers of turbines in the Goto Islands.

Plot showing the mean power available from various numbers of turbines in the channels of the Goto Islands, using simplified M2 tides.

Just a few weeks ago I attended the EWTEC conference in Cork and presented this paper on Lashy Sound, which is a channel with strong tides in the Northern part of Orkney. In this work, I used very similar methods to those that were developed in Japan to look at the tidal resource – in this case, not for realistic turbine developments but in terms of the theoretical maximum available power if we didn’t care about things like environmental impact, or allowing ships through. Unsurprisingly, it looks like achieving this maximum yield would have some significant impacts. I also considered the more plausible scenario of a smaller tidal farm, similar to the 30MW one that has been planned for the area, and was able to show that its effects would be small and confined to Lashy Sound itself – something that’s important when other potential tidal energy sites are just a few km away in neighbouring channels.

Both of these papers are available for free at the links above, or at the publications page on this site.

Posted by simon in Explaining my work, Publications, Working in Japan

Farewell to Pelamis

One of the perks of living in Stromness, just a few minutes walk from EMEC‘s offices, is that I get to see some of what’s going on behind the headlines. Right now, something that’s going on is the decommissioning of one of the Pelamis P2 machines (the one belonging to Highlands & Islands Enterprise).

This most famous of wave energy machines was divided into its five sections, and each section lifted onto a barge. They were then cut into small enough pieces for road transport, and taken from barge to workboat and workboat to truck. I was able to grab a few photos of the last part of this process.

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I perceived Pelamis as the “poster boy” for marine renewables, and I think many others did too. It was the machine that my friends, and sometimes even my mum’s friends, had heard of. The industry was always going to have to deal, at some point, with one of the big companies failing, and there’s no reason to extrapolate from this to the fate of wave energy as a whole. However, it did feel very poignant.

Posted by simon in The wider world