| Archive for Downsizer For an ethical approach to consumption |
| Behemoth |
Orkney to get 'biggest' wave farmhttp://news.bbc.co.uk/1/hi/scotland/6377423.stm |
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| Green Man |
Looks good to me. I have sailed here and know the energy in the water. On a simmilar note, the Scottish Government have announced a new £1bn Forth road crossing. Why could this not incorpotate a tidal generation plant also? | ||||
| Northern_Lad |
Ah, but wait 'til they want to set up a farm and all the NIMBYs complain that it's ruining their view.
Don't get me wrong, I'm all for it - just about the most reliable form of energy production (I think tidal and geo-thermal win that one) - it's just that some people won't like it as it will 'cost' them. |
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| Penny Outskirts |
You've sailed in the Pentland Firth 
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| Green Man |
Yes, I've sailed as far as Whalsey in the Shetland Isles to the North, St Kilda to the West, Campbelltown to the South West, and down to the Farne Islands on the East and been through the Gulf of Corryvreckan all in our 21ft, 35year old yacht. I want to go to Norway and the Faroes  but my wife won't let me. 
(Once when we arrived at Stornoway Harbour we got a round of applause for being the smallest boat to cross the Minch that year) |
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| Penny Outskirts |
Very impressed! That's one very very rough stretch of water And I don't blame your wife at all....
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| Green Man |
Both times we crossed the Pentland it was in the month of June,about a westerly force 3. We timed it just right and went with the flow. It would be a different story if it was stormy winter with wind and tide against you.
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| Penny Outskirts |
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| dougal |
There's a connection here. Tidal barrages get their energy from delaying the tide and then letting it through in a rush. The energy you get out depends on the 'head' (water level difference) that you produce for the turbines. The result is flow rates (and potentially turbulence) that make even the fearsome Corryvreckan seem tame. Oh and the water level has to change faster than it would naturally, as a result of compressing the time for the tidal cycle. Not a good idea for a water body in a populated area that is used by shipping, let alone small boats... |
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| Green Man |
Can't the turbines gently turn as the tide passes through them. Almost like underwater windmills, without the need to hold back the flow? | ||||
| dougal |
Well, they *could* {barely hold back the flow}. But they wouldn't produce much power, turning 'gently' in a gentle flow which is unbounded and free to flow around them. Such 'underwater windmills' have been proposed for some of those narrow tidal races in the Western Isles - where the water is, not least, much faster flowing. One important consideration to bear in mind is that water is not just more dense than air, but that its much more viscous too (so the drag losses are higher). Efficient designs of wind and water turbines are rather different. And lets remember that "efficiency" comes down to watts per £. |