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World's Largest Tidal-powered Energy Farm


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Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)

'Three sites are under investigation - two off Scotland and one off the coast of Northern Ireland - for up to 60 underwater turbines, generating 60 mega watts of power for 40,000 homes'

I think this is great news and a positive step forward for alternative energy sources - but then it's not in my back yard! (no I'm not a NIMBY really :( ) how do you feel?

ukpress.google.com news.bbc.co.uk

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Guest Shetland Coastie
'Three sites are under investigation - two off Scotland and one off the coast of Northern Ireland - for up to 60 underwater turbines, generating 60 mega watts of power for 40,000 homes'

I think this is great news and a positive step forward for alternative energy sources - but then it's not in my back yard! (no I'm not a NIMBY really :( ) how do you feel?

ukpress.google.com news.bbc.co.uk

I think its an excellent idea and far better than those eye-sore wind farms! We already have these undergoing testing down at the Falls of Warness in Westray Sound, Orkney, so obviously they have proven to be successful. We have to look at alternatives and start to wean ourselves off of fossil fuels. Absent any impact Global Warming-wise, there are a whole load of othger reasons why this is so, not least of all that most of the worlds fossil fuels come from unstable parts of the world and the sooner we can tell the Arabs and the Russians where to stuff their oil the better we will be IMHO.

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Posted
  • Location: Aberdeen, Scotland
  • Location: Aberdeen, Scotland

Can't help wondering how the sounds (and there will be some) from those underwater turbines will affect sealife - especially the cetaceans. They're finding out now that the sudden air pressure changes around wind turbines cause bats to die - will there be a similar affect with sudden water pressure changes? Any studies done on this sort of thing?

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Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
Can't help wondering how the sounds (and there will be some) from those underwater turbines will affect sealife - especially the cetaceans. They're finding out now that the sudden air pressure changes around wind turbines cause bats to die - will there be a similar affect with sudden water pressure changes? Any studies done on this sort of thing?

According to Wki, potential environmental impacts are likely to be (for basin systems):

Turbidity

Turbidity (the amount of matter in suspension in the water) decreases as a result of smaller volume of water being exchanged between the basin and the sea. This lets light from the Sun to penetrate the water further, improving conditions for the phytoplankton. The changes propagate up the food chain, causing a general change in the ecosystem.

Salinity

As a result of less water exchange with the sea, the average salinity inside the basin decreases, also affecting the ecosystem "Tidal Lagoons" do not suffer from this problem.

Sediment movements

Estuaries often have high volume of sediments moving through them, from the rivers to the sea. The introduction of a barrage into an estuary may result in sediment accumulation within the barrage, affecting the ecosystem and also the operation of the barrage.

Fish

Fish may move through sluices safely, but when these are closed, fish will seek out turbines and attempt to swim through them. Also, some fish will be unable to escape the water speed near a turbine and will be sucked through. Even with the most fish-friendly turbine design, fish mortality per pass is approximately 15% (from pressure drop, contact with blades, cavitation, etc.). Alternative passage technologies (fish ladders, fish lifts, etc.) have so far failed to solve this problem for tidal barrages, either offering extremely expensive solutions, or ones which are used by a small fraction of fish only. Research in sonic guidance of fish is ongoing. The Open-Centre turbine reduces this problem allowing fish to pass through the open centre of the turbine.

Recently a run of the river type turbine has been developed in France. This basically is a very large slow rotating Kaplan type turbine mounted on an angle. Testing for fish mortality has indicated much lower mortality figures, less than 5%. This concept seems very suitable for adaption to marine current/tidal turbines also.

Also: http://jrscience.wcp.muohio.edu/fieldcourses04/

Another environmental impact on aquatic ecosystems by building barrages is how will tidal stations affect plants and animals living in the basins. The barrages will restrict these aquatic organisms movements and no longer allow them to move with the tides. The only way to leave these areas is through the flow of water through a turbine, which will destroy most organisms.

Open water turbines have environmental impacts as well; figure 3 shows that there is no protection for organisms crossing these turbines. It looks like there will be a lot of organisms harmed by the blades of the turbine if there is no protection from them.

I can't find any current, specific reports on other negative effects of the technology on marine life. I suspect it is far less than what Scottish trawlermen have to throw back at the moment.

Edited by Coast
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Guest Shetland Coastie

If it were sited in the Pentland Firth for example some of what you mention would be mitigated by the fact that the Firth has an extremely fast flowing tidal stream which at times can approach 15 knots. So much so that even modern vessels will have difficulty navigating the Pentland Firth and will avoid doing so in such conditions. Furthermore the Pentland Firth is also one of the roughest stretches of water around the UK, particularly in the area between the southern tip of Hoy and the mainland, an area known as the Merry Men of Mey. The Pentland Firth therefore, is already well stirred up by the action of sea and tide so adding turbines to an already highly turbid stretch of water shouldnt be a problem and, as there is a rapid throughput of water, maintaining the salinity shouldn't be a problem.

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

In 1974 13 'scientists' were given the brief to investigate alternative energies at the height of the then energy crisis. It has taken all of this time to arrive back at the same spot. Back then 11 of the 13 were in the employ of UKAEA so you can guess which option proved most 'popular'. Sadly the most competitive technologies did far worse than they ought by the crafty shifting of a few decimal places in some of the viability studies..........how naughty was that???? Up until the late 90's the mainly conservative opposition to alternative energies held up the same study as 'proof positive' that the technologies were uncompetitive. The Severn barrage, though with sedimentation issues, could provide a fair whack of SW U.K.'s energy needs as could the geothermal to be gained from the Batholiths under the SW/Derbyshire/lots of Scotland esp. with the advances in drilling technology since th 70's.

Does anyone wonder why the most visually intrusive method of producing energy was the one favoured by the then conservative govt. in the late 80's early 90's?????

Geothermal,wave,tidal and hydro get my votes.

In so far as wildlife impacts are concerned...what fate for them if we do nowt but find new ways of extracting coal, gas and oil and further compound the changes the plant is undergoing???? better a few casualties than extinction I say.

Edited by Gray-Wolf
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Posted
  • Location: Orleton, 6 miles south of Ludlow
  • Location: Orleton, 6 miles south of Ludlow

Great idea — anything to get away from oil and nuclear, especially nuclear which comes with all the horrendous issues regarding what to do with the waste.

No matter which energy route we choose there will always be animal/bird/insect casualties either short or long-term, or in some cases, both. There is no perfect solution I expect, but at least "green" energy does not pollute the environment.

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Posted
  • Location: Aberdeen, Scotland
  • Location: Aberdeen, Scotland
Better a few casualties than extinction I say.

As we are probably the worst thing that ever happened to this planet, maybe we should not be so flippant about a 15% mortality rate from an already threatened piscine ecosystem.

On a not-quite-serious note, I think we should hook up all of the treadmills & stationary cycles, used in the multitudes of gyms around the country, and generate power from them. Maybe everyone should be made to do a daily 1/2 hour inside a large 'hamster wheel' (put them on every street corner), which could be used to generate electricity. This would also solve some of the general weight/lack of exercise/health issues we have as well. Maybe those who cycle about can have a device that charges AA batteries up while they cycle - as well as their lamps. There are enough people on this planet so maybe we should harness the energy from their general daily activity. Make them earn the CO2 they exhale.

Great idea — anything to get away from oil and nuclear, especially nuclear which comes with all the horrendous issues regarding what to do with the waste.

Re: nuclear - just popping this in - saw it during my troll of various websites this morning and this post brought it to mind. The current views of a longtime Green party member.

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Posted
  • Location: Portlethen - Aberdeenshire
  • Location: Portlethen - Aberdeenshire
'Three sites are under investigation - two off Scotland and one off the coast of Northern Ireland - for up to 60 underwater turbines, generating 60 mega watts of power for 40,000 homes'

I think this is great news and a positive step forward for alternative energy sources - but then it's not in my back yard! (no I'm not a NIMBY really ;) ) how do you feel?

ukpress.google.com news.bbc.co.uk

I'm all for saving the planet etc but it doesnt really seem worth while...40,000 homes (666) per turbine, i'd shudder the thought at the expense it will cost to make these and install them!!!

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Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
If it were sited in the Pentland Firth for example some of what you mention would be mitigated by the fact that the Firth has an extremely fast flowing tidal stream which at times can approach 15 knots.

Something looks likely acording to the Crown Estate:

news.bbc.co.uk

'The Crown Estate has outlined the process and timetable for granting approval for wave and tidal energy projects in the Pentland Firth'

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Posted
  • Location: Warminster, Wiltshire
  • Location: Warminster, Wiltshire

There are similar ideas to harness tidal power in the Severn Estuary, but the plans for a 'Severn Barrage' are not exclusively to do with power with flood prevention in there too.

The below links are the first three on a Google results page searching for 'Severn Barrage'...

http://en.wikipedia.org/wiki/Severn_Barrage

http://www.reuk.co.uk/Severn-Barrage-Tidal-Power.htm

http://www.telegraph.co.uk/earth/main.jhtm...easevern101.xml

As far as harnessing natural power for the good of us all I would be all for it, however the area is an amazing natural site for wildlife of all varieties as well as a big player in weather that moves in from the NW/W/SW - I would wonder if building the barrage would effect the development/distribution of showers and storms.

However I am all for wind turbines and wish the go ahead would be given for some on Salisbury Plain, it's just so exposed and wild up there that they wouldn't need to be seen by those who think them an eyesore - I originally thought they could be an eyesore, but in 2006 I saw the ones off the Norfolk coast which look just like yachts on the water!

Edited by Andy Bown
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