Just been reading the latest news reports about tidal barrages and nuclear power
Why does no one mention HEP as a renewable source of energy any more?
Surely there must still be some areas of Wales and Scotland along with bits of Northen England that would be ripe for building dams and flooding. May also be beneficial for flood control further down the valleys.
Can it really be more expensive than new nuclear stations?
While there would be scope to build more Dinorwig style pumped storage facilities, these are net users of power rather than generators. True HEP generation requires a georgraphy and rainfall predisposed to it that we don't really have much off. The amount of power available through natural HEP would be fairly minuscule in the grand scheme of things.
A work through the numbers is quite revealing:
Not only more expensive, but more importantly not able to generate in sufficient quantity.
I am sure I have heard knowledgable people talking about dams. The message was that we don't have enough flow in most of our rivers to make hydro dams viable. Tidal can be used where there is a sufficient tidal rise and fall, but it seems we haven't many places for that either. The Rance barrage in Brittany works fine but the tidal range there is amazing to watch. Can't give a figure off-hand but I visited a few weeks ago and didn't believe that the sea would rise high enough to cover the tidal marks on the rock outcrops. The Severn and Morecombe Bay are OK but the length of barrage in each case makes it horribly expensive.
Peter Scott
The short answer is that if the land topography and rainfall is right HEP is THE cheapest way to make leccy.
Unfortunately, if its not, its a waste of money.
I suspect there are few UK sites suitable left..there is a distinct conflict between destroying thousands of acres of habitat and cheap HEP ;-)
On Mon, 18 Oct 2010 12:20:55 +0100 someone who may be "TMC" wrote this:-
They do. For example Scottish Renewables
The NoSHEB identified a number of schemes early on. Roughly half of them were built, so there is the potential to install at least twice as much hydro here as there currently is.
The same sort of people who object to wind turbines also object to hydro though, the landscape lobby.
NoSHEB just looked at relatively large schemes, there is also potential to convert every former water mill into a small generating plant using low-head forms of engineering, not just in Scotland. An example in England is .
The first new large scale hydro scheme for decades, Glendoe, has already been opened, but suffered from a rock fall in the tunnel
Plans to convert Sloy to pumped storage have also been approved
Pumped storage is not a perpetual motion machine, they consume more electricity than they produce, but their flexibility is a great way of matching supply with demand. For a short period they can produce far more electricity than a "conventional" hydro station on the same site.
But we do have an awful lot of water reservoirs obstenishly for drinking water but most if not all let down water all the time to keep the rivers below them flowing. One could harness this let down for power generation.
It probably wouldn't be a great deal at any single reservior, maybe a few MW, but not far from here there are a series of reserviors all letting down one to the other. It starts to add up and apart from maintenace and faults it would be 24/7 power.
No one single renewable energy soure stands a chance of supplying all the enregy demanded but that is *not* a reason not to use renewables.
No-one has really discussed the Severn estuary for tidal power. The schemes put forward have been in the Bristol Channel, which is downstream of the estuary, enormously wide and an impractical scale for anyone except the Chinese to contemplate barraging.
The Severn estuary is an awkward river. It's not as big as you might imagine: although very wide it's also very shallow across almost all of this width and there's only a narrow navigable channel, which both tidal and shipping needs would be fighting over. Tidal flow turbines in the narrower part of the Severn (even the Usk, Wye or Avon) would be an interesting idea and far cheaper than a barrage on the Severn, but the effect on navigation would make them most unpopular.
I'd like to see tidal flow turbines in the Bristol Channel, but free- flow turbines, not a barrage.
It was the first to be lit by hydro-generated electric light. There were several others in town centres (including AFAIR, Armstrong's own townhouse) that were lit by electricity beforehand.
On Mon, 18 Oct 2010 13:51:13 +0100 someone who may be "TMC" wrote this:-
Foyers and Cruachan in Scotland. Ffestiniog and Dinorwig in Wales. Sloy will be an interesting conversion.
A little harsh. As well as being against hydro and wind the landscape lobby were also against the overhead lines that connect them with the rest of the system. A great fuss was made when NoSHEB put up these lines in the Highlands, the same sort of people made a fuss again when the upgrading of one of these lines was approved. The letters pages of the newspapers were full of angry letters, they were even more critical of organisations like Friends of the Earth Scotland which supported it.
They would make a useful contribution and if community owned the profits would go back to the community.
On Mon, 18 Oct 2010 17:33:27 +0100 (BST) someone who may be "Dave Liquorice" wrote this:-
Since water privatisation (down south) they have been doing this. Extra profits for little extra work.
On Mon, 18 Oct 2010 09:20:22 -0700 (PDT) someone who may be harry wrote this:-
has an interesting discussion of the pros and cons of that particular scheme.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Tim Streater saying something like:
Not up my back yaris?
In the context of the OP, you are not going to replace many modern nuke plants with HEP. However I agree, it can be worth doing in some circumstances. Sadly I expect the main reason people will do it is to milk the system either for feed in rates, or for renewables credits rather than because its makes sense for other reasons. Both of which just mean that jo consumer is copping the bill on their domestic usage.
Average tidal range is 8 metres. The Severn has slightly more. You may have hit springs, which are over 12 metres.
Of course it doesn't run 24 hours. It's nicely predictable though, and I guess a few dozen pumped storage schemes could buffer up the power for slack tides. So long as we don't mind filling every valley in the Brecons with water twice a day.
Andy
Trouble with the Severn barrage jobby is you spend billyuns before you see a single watt-second in return.
Tidal stream would do a lot better. But like anything else, you're talking a not-huge %-age of the total need.
A mile from my old home, there is now a firm proposal for a small hydro installation at Teddington Lock - see
On Mon, 18 Oct 2010 20:47:04 +0100 someone who may be John Rumm wrote this:-
Feed in Tariff is for small scale systems, so operators of large scale hydro schemes will get nothing from it.
Jo consumer paid £9 a year on the average electricity bill a few years ago for the Renewables Obligation.
How much power is this project expected to produce? What is it expected to cost? What is its expected lifetime? What are its annual maintenance and running costs?
Cost effectivness is. None of the renewables can match the generating cost of conventional or nuclear power and, if you do a whole life study, when nuclear still wins out on cost, wind farms generate a lot more CO2 per MWh than nuclear.
Colin Bignell
"Under our plans, the scheme will generate enough electricity to power 600 homes ..."
I hate that measure as it can be twisted by the spin doctors. Generally a "household" is taken to be around 1kW, so this plant is probably 400 to 600kW.
Must admit the link above is sadly lacking in any real information and the number of paper shuffling office wallas in the team list is not a good sign.
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