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Author Topic: Tidal Power  (Read 8124 times)
Big Wal
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« Reply #15 on: August 17, 2011, 09:57:46 AM »

Sorry Martin about the reading matter, surrender but I was unable to get the Tim---s or Nud words, so I take whats left on the returns heap thats going back 1/3rd of price on mondays. M I do agree.
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martin
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« Reply #16 on: August 17, 2011, 10:08:50 AM »

No worries! Grin
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Unpaid volunteer administrator and moderator (not employed by Navitron) - Views expressed are my own - curmudgeonly babyboomer! - http://www.farmco.co.uk
HalcyonRichard
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« Reply #17 on: August 17, 2011, 10:34:38 AM »

Hi all,
       Quite fascinating. But I always take any information with a rather large pinch of salt. Any system will have losses and downtimes. Oil and gas waste vast amounts of fuel because of flare offs and innefficient fuel pipelines and transport - not to mention refining oil to give diesel and petrol.

If you worked out the percentage loss for this it would be incredibly small. It's a bit like saying I waste energy when I go out of the living room for  5 minutes and leave the television on. Every time a car is stuck at traffic lights when there are no other cars around a teaspoon of fuel is wasted small for the individual but a massive waste if taken for all cars for a year. Intelligent traffic lights would save time and money and fuel.

There is no doubt a grid desigend in the 1950's and 1960's is totally inappropriate for todays needs. Shutting down a whole windfarm (if it is true) is a nonsense capping output at a level could be done very easily. Use of a smart grid could cope with all output with no problem.

Also we pay a massive amount of money for standby reserve and "spinning" reserve with the current non renewable fuels no one seems concerned about this enormous cost and waste.

The term well thought out and  informative  should not be used for this type of article.

Regards Richard
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« Reply #18 on: August 17, 2011, 01:41:29 PM »

Here's my calculation on the tidal-range resource available to English estuaries (and those England shares with Wales or Scotland). The long and short of it is 5.57GW of electricity, mean power. That's about 2.8% of our current final energy demand, so it's significant enough to be worth doing.

It's the most predictable form of power we've got. Most of the infrastructure, built well, should last for more than a century; and as sea levels rise, we'll be building flood defences anyway, so we may as well get on with it and build them now, and build them for generation as well as flood defence. It's uncorrelated with wind, with wave and with solar, so it complements them very well and adds a lot of security through diversity to the grid.

If built right, with over-pumping, you can build an hour or two's effective storage into them as well, to provide some really valuable balancing services into the grid twice a day.

And, rather elegantly, high tide takes about a full day to travel around the entire British coastline, which means that the generation gets reasonably spread out across the day. Of course, they all follow the moon's cycle, but at least the diurnal cycle is somewhat smoothed (not completely, because the Severn is so much more powerful than the others).
« Last Edit: August 17, 2011, 02:13:50 PM by azps » Logged

tz0c0s
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« Reply #19 on: August 17, 2011, 01:56:27 PM »

Quote
Possible storage of excess wind!

Documentary on renewables a few years ago, and one portion of the program featured an American bod (ex NASA or aeronautical engineer, something like that) he has built his own fuel cells for his house and car. He has too much solar on his property, and when it produces an excess he uses it to produce hydrogen, which he stores in large, low pressure tanks. When he needs extra leccy he runs the house fuel cell. He converted his car himself!

No idea what the efficiency of this is, but surely anything is better than nothing rather than switching the wind off, so to speak.

Martyn

For anyone that is interested, Mike Strizki & the Hydrogen Home. Google & YouTube are your friends.

Regards Andy
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stuartiannaylor
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« Reply #20 on: August 18, 2011, 02:47:51 AM »

The 900,000 payment was true but it was due to the national grid not being able to redirect through lack of infrastructure in that area. Basically the grid was maxed out and yes the wind farm was paid because the fault wasn't theirs.

Tidal has taken a back seat as perfectly safe and cheap nuclear power is so much better, just ask a freind from Japan.
http://www.guardian.co.uk/environment/2010/oct/18/severn-barrage-nuclear

Then again this dude who is deservedly a dude of the highest acolade was a little upset as he did all the groundwork and the for some reason the government decided rolls royce should get the contract.
Rupert Armstrong-Evans http://www.evans-engineering.co.uk/
"The Severn Tidal Reef Project is the focus of the largest tidal scheme proposal in the World, with an annual output that could exceed 15 Twh or around 5% of the UK electricity requirement. With over 600 turbines, each in excess of 15 metres in diameter, the project is truly staggering in its scale. It is somewhat surprising that a small family business should even get involved with such a proposal. If it is of interest, you may like to follow the link or go directly to www.severntidal.com"

The sooner we get accross the board level subsidies on all green technologies and remove politicians and also reward on "usefull energy" produced.

PV obviously peaks at midday what isn't so obvious is the time of the peak is about as usefull as a chocolate kettle.
« Last Edit: August 18, 2011, 02:50:26 AM by stuartiannaylor » Logged

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mikey9
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« Reply #21 on: August 18, 2011, 06:59:39 AM »

Remeber the "Pure" energy project in Unst (Shetland) - Hydrogen from excess wind


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M
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« Reply #22 on: August 18, 2011, 07:30:35 AM »


PV obviously peaks at midday what isn't so obvious is the time of the peak is about as usefull as a chocolate kettle.

I'm confused, were you being satirical, or did you really mean this?

Perhaps I've confused myself (nothing new there) but every report or study I've read shows peak electricity demand and PV production both follow the same curve, rising from 6am, peaking midday and then lowering till 6pm, with demand from 6pm to 6am being relatively flat, give or take Britain and Eatenders kettle boiling.

In hotter climes, PV production matches A/C use (for obvious reasons).

Confused of Cardiff.
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Just call me Mart.     Cardiff: 5.58kWp PV - (3.58kWp SE3500 + 2kWp SE2200 WNW)
stuartiannaylor
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« Reply #23 on: August 18, 2011, 05:28:38 PM »

Have a look http://www.nationalgrid.com/uk/Electricity/Data/Realtime/ and in winter its much worse.

Its essential to provide a balance between all forms of green technology. We need diversity by technology and generation time.

We have the oppisite mostly wind with a bit of solar. This is due to awarding certain technologies higher subsidies and all the government u turns has created such a massive uncertainty that many are unwilling to invest.
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M
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« Reply #24 on: August 18, 2011, 05:45:32 PM »

Sorry Stuart, not trying to start an argument, honest. I absolutely agree that we need as wide a range of supply as possible, and that the UK is blessed when it comes to wind power.

I live in Cardiff and we used to have a holiday bungalow at Lavernock Point, the point where the barrage is usually suggested as joining Wales. It would be some sight and hopefully of great use.

My confusion however was with your remark that seems to suggest that PV peaks don't help with demand peaks, but surely PV does exactly that. The link you posted shows demand being higher during 'daylight' hours (appreciate less PV in the winter) and peaking around mid day. Isn't that what PV does, and not partially does but exactly does?

PV will never solve our problems as we are a bit too north. But if it can at least add something, and more importantly during peak times then it must be useful to help balance demand a little.

Why do I get the feeling I'm completely misunderstanding this?

Martyn
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Just call me Mart.     Cardiff: 5.58kWp PV - (3.58kWp SE3500 + 2kWp SE2200 WNW)
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« Reply #25 on: August 18, 2011, 06:07:13 PM »

Hi Martyn,

no, PV isn't a great match to our annual pattern of energy demand. We have a bit of cooling in summer, and a lot of heating in winter.

Nevertheless, it is a very good match to some loads:air-conditioning being the obvious one.

The extreme seasonality of PV generation means it probably can't meet more than 10% of our electricity needs economically; and that the economic option is probably somewhere in the range 1-5%.

It does depend how much wave power we have on the grid: wave has almost the opposite profile to PV, with very high forecast generation in winter, and very low in summer. So a blend of those two could work well.

The very highest electricity demands happen around 17.00-18.00 on very cold winter days.

Andrew
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Wyleu
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« Reply #26 on: August 18, 2011, 07:13:56 PM »

Nowhere nearly ambitious enough ! :-)

Build two sea walls with railways and roads on top across the Irish sea between Angelsey & Northern Ireland and a similar structure, Fishguard to Eire. Cover the structures in wind turbines and install water turbines in the walls and control the pool depth.

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« Reply #27 on: August 18, 2011, 07:56:02 PM »

azps - cheers, see your point re annual demand, I was stuck thinking about daily.

Wave power has got to be in Britain's future, but it tends to break everything that is thrown at it.

Tidal power and the Severn barrage is such an interesting idea, but apparently the combination of large tidal range and large storage is rare. Of the top 20 sites in Britain, the Severn barrage has more potential than the other 19 put together.

Speak to most people around here (I go for a walk each day to a small local lake and you can see across the Bristol Channel to Western Super-Mare) and they'll happily tell you how the barrage will block the incoming tide during storm surges and high river levels and how the area around Lavernock (Barry and Penarth) will all get flooded. I've tried pointing out that water isn't very good at 'sloping' and any load will be shared out with the rest of the British western coast, but they won't have it. 'It'll be 3 feet higher and whose gonna pay for the damage?'

Another idea for wave power was in a recent New Scientist I read:-

Battery boats. You send a large boat out full of batteries and long arms that extend out for some distance. The ends of the arms have floats and will go up and down creating hydraulic action on the boat and generating electricity. When the boats are full, or storms are due, bring them into safe harbours and discharge when demand calls for it.

Sounds complex but saves on the cost of cabling, storm damage, and the need to build wave power devices that are in themselves over-engineered to survive a storm. Sounds futuristic but interesting.

Martyn
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Just call me Mart.     Cardiff: 5.58kWp PV - (3.58kWp SE3500 + 2kWp SE2200 WNW)
billi
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« Reply #28 on: August 18, 2011, 10:10:57 PM »

Hi Wyleu

Quote
Build two sea walls with railways and roads on top across the Irish sea between Angelsey & Northern Ireland and a similar structure, Fishguard to Eire. Cover the structures in wind turbines and install water turbines in the walls and control the pool depth

Beside the renewable  idea it could result in a better Guinness in  London  cause travelled by train  facepalm
http://onlinelibrary.wiley.com/doi/10.1111/j.1750-3841.2010.01986.x/abstract

with kind regards Billi
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« Reply #29 on: August 19, 2011, 08:18:12 AM »

Hi Billi,

You see it's the un-measurables that really decide these issues !
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