Sadly there isn't enough motive power in the UK's watercourse to generate the energy required to purify our water. There are other things the water company are doing

[urlhttp://www.thameswater.co.uk/cps/rde/xchg/corp/hs.xsl/9849.htm#[/url

It's a good old fashioned 'where there's muck there's brass' story.

From memory it was so the government could put the money of the sell-offs into their country's coffers for the benefit of us all. And provide competition that would help keep the costs of the products down. For the benefit of us all.

Is that not the case? [size=85(I'm guessing I'd use the sarcasm emoticon here, but can't find it).[/size



I just realised from schoolboy german where the word Koffer may come from.

Fair point. McLF. Watched a programme on BBC Knowledge over here the other day about wave technology and how brilliant it is.

I've always been of the opinion that necessity company's should be nationally owned, utilities, public transport, farming industry.

The only worry i have with those though is instead of the private companies ripping us off to pay their shareholders and cream off a tidy pay for their directors is the unions holding us by the baby factories whenever they want a way over inflation pay rate and then threatening strikes when they don't paid way more than they worth, <cough> tube workers <cough>
The only thing i like about that is the little man ripping me off is easier to take than the already rich.

I have often wondered about this. For example, having some idea of the tremendous weight that water has, and having watched rivers eg the Aire in spate at Saltaire, I often think of just how much power there must be passing by per second. So multiply that by the UK, and whichever way you look at it, it must surely be a monumental untapped (sorry!) resource.

But how much motive power is there? I am no scientist, nor mathematician but somebody must have worked it out, in order to say there isn't enough motive power. I am not disputing that answer, but the fact there isn't enough ain't the point, why don't we tap into this free resource more than we do?

Anyway some of you who do maths may be able to help. On the back of my fag packet it says that average rainfall is broadly speaking 1 litre; the approx area of the UK is 250,000 sq km; I have no clue what the average height above sea level is, but if it was for the sake of argument 10m, then on average, wouldn't the annual motive power nominally available be the amount it would take to raise that volume of water to that height? And what would that figure be?

[url=http://images5.cpcache.com/product/115511515v2_460x460_Front.jpgI have the answer ...[/url

Quote Ferocious Aardvark="Ferocious Aardvark"I have often wondered about this. For example, having some idea of the tremendous weight that water has, and having watched rivers eg the Aire in spate at Saltaire, I often think of just how much power there must be passing by per second. So multiply that by the UK, and whichever way you look at it, it must surely be a monumental untapped (sorry!) resource. But how much motive power is there? I am no scientist, nor mathematician but somebody must have worked it out, in order to say there isn't enough motive power. I am not disputing that answer, but the fact there isn't enough ain't the point, why don't we tap into this free resource more than we do? Anyway some of you who do maths may be able to help. On the back of my fag packet it says that average rainfall is broadly speaking 1 litre; the approx area of the UK is 250,000 sq km; I have no clue what the average height above sea level is, but if it was for the sake of argument 10m, then on average, wouldn't the annual motive power nominally available be the amount it would take to raise that volume of water to that height? And what would that figure be?'" The UK doesn't have the necessary river volumes, consistent flow rates, natural storage (lakes etc.), or natural drops for large scale hydroelectric power generation. There are a handful of decent sized hydro power stations, one in Wales and the others in Scotland. All but one of them (IIRC) use a storage method where excess capacity in the Grid is used to pump water uphill to a reservoir of some sort and then during peak demand that water is allowed to flow back downhill through the turbines. As you can tell the net contribution is zero - it just helps balance peak load. There are a fair number of small scale hydro power developments that provide power for a residence, busines, or maybe small community. That's pretty much the limit. We could use more of these schemes but we're never going to generate a significant amount of hydroelectric power in the UK - we simply don't have the geography for it. A couple of links for those interested: www.british-hydro.org/index.html www.reuk.co.uk/UK-Hydro-Power-Stations.htm

Quote Ferocious Aardvark="Ferocious Aardvark"I have often wondered about this. For example, having some idea of the tremendous weight that water has, and having watched rivers eg the Aire in spate at Saltaire, I often think of just how much power there must be passing by per second. So multiply that by the UK, and whichever way you look at it, it must surely be a monumental untapped (sorry!) resource. But how much motive power is there? I am no scientist, nor mathematician but somebody must have worked it out, in order to say there isn't enough motive power. I am not disputing that answer, but the fact there isn't enough ain't the point, why don't we tap into this free resource more than we do? Anyway some of you who do maths may be able to help. On the back of my fag packet it says that average rainfall is broadly speaking 1 litre; the approx area of the UK is 250,000 sq km; I have no clue what the average height above sea level is, but if it was for the sake of argument 10m, then on average, wouldn't the annual motive power nominally available be the amount it would take to raise that volume of water to that height? And what would that figure be?'" The UK doesn't have the necessary river volumes, consistent flow rates, natural storage (lakes etc.), or natural drops for large scale hydroelectric power generation. There are a handful of decent sized hydro power stations, one in Wales and the others in Scotland. All but one of them (IIRC) use a storage method where excess capacity in the Grid is used to pump water uphill to a reservoir of some sort and then during peak demand that water is allowed to flow back downhill through the turbines. As you can tell the net contribution is zero - it just helps balance peak load. There are a fair number of small scale hydro power developments that provide power for a residence, busines, or maybe small community. That's pretty much the limit. We could use more of these schemes but we're never going to generate a significant amount of hydroelectric power in the UK - we simply don't have the geography for it. A couple of links for those interested: www.british-hydro.org/index.html www.reuk.co.uk/UK-Hydro-Power-Stations.htm

So is the issue then an inability to meaningfully store up hydro-generated electric power, when generated?

You see, I can easily see a system whereby a whole bunch of electricity could be generated by installing turbines to tap into the strong flow of water down the Aire at Saltaire (or wherever). This electricity if fed into the grid would reduce the need to generate it by burning fossil fuels to an equivalent amount.

On a more epic scale, one resource the British Isles has is we are in the middle of a set of very tidal seas, and almost 24/7 there is an unstoppable flow of trillions of gallons of water either coming in or going out. Surely, if we could harness the power of nothing more than the flow of water, which will flow whether we harness it or not, it would generate a very significant amount?

OK, so I'll have a punt at this. You can challenge all of my assumptions as you like.

OK, so 1 litre of water falls on each square cm per year (I think that's your statement). That gives us a pulsating 2.5x10^15 litres of rainfall in the UK per year. (2,500,000,000,000,000 litres).

Nicely enough, that's the same number of kilos of rainfall. OK, so if we with 100% efficiency extract 10m of potential energy from this water (PE = mass x g x height) we get 2.45x10^17 J of energy (per year).

There are 31.5 million seconds in a year, so the power output is 2.45^17 divided by 31.5^6. Which is about 8000MW, or the output of 2-3 coal fired power stations.

Clearly we won't a) get our hands on all the water or b) get 100% efficiency from our mythical PE recovery engine.

I think the key point is that you need the big drop to get the power output through a tubine that would even approach this sort of efficiency.

No. The issue is that just sticking a turbine in a river delivers very little electricity and is impossible to control as the flow in the river is constantly varying. This is why the vast majority of hydro power is delivered by falling water from some sort of reservoir - typically an artificial lake formed by damming a major river.

There are 'run of river' hydro plants that don't use a reservoir (or at most a very small one) but these still require a large river with constant flow and a significant drop in order to ensure sufficient water through the turbine under controllable conditions.


See above. The contribution would be tiny and quite possible outweighed by the environmental and energy costs of building, installing, and maintaining the generators.


Tidal power is a whole different ball game and well worth pursuing. Sadly successive administrations have been swayed by the extremely active wind power lobby and most of the development funding has gone into wind turbines. However, there is now some promising activity in this field and hopefully we can realise it's potential. The UK has nearly 50% of the sites identified as suitable for large-scale tidal arrays in the world (8 out of 20 at last count I think) and some estimates claim that tidal could produce as much as 20% of our energy requirements.

I remember reading articles about hot rocks power in [iNew Scientist[/i, way back in the 1980s: any advances on that or is it unlikely, does anyone know?