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back to article How politicians could end droughts FOREVER: But they don't want to

Last month in old London town and across England, formal water rationing came into force again for the second time in just six years - and the creeping rationing of water meters continued to spread. Despite the rainiest April since records began, government minsters are openly speculating that total mains cutoffs and standpipes …

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Joke

How dare you!

Suggest we should use few pence worth of electricity more for such bourgeois comforts as watering our gardens or washing cars!!

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Re: How dare you!

lol indeed.

Lewis for London Mayor, then for PM!

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Anonymous Coward

Desalination will never work...

...as the excess waste salt mountains will bring soaring cancer rates and cause house prices to plunge leading to gangs of feral youths roaming the streets.

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Happy

Re: Desalination will never work...

But at least we can salt the roads when the ice age come back...

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Boffin

Re: Re: Desalination will never work...

"....the excess waste salt mountains...." Salt is a valuable commodity (http://en.wikipedia.org/wiki/Sea_salt), there are actually countries in Europe where artificial lagoons are created each year, allowed to dry up to form salt pans, which are then bulldozed to gather the salt. Such methods of gathering sea salt have been going on for centuries (minus the bulldozers, of course).

But the main byproduct would not be salt, it would be the sludge that is in all our river water, even the relatively clean Thames. I'm assuming the majority of the Beckton plant's power consumption if the actual processing to get rid of the mud and other pollutants in the water (and hopefully the bacteria), leaving what is probably a rather nasty sludge behind which would have to go to either landfills or back into the river.

As regards power and carbon silliness, I do know that it was advertised that the Beckton plant runs on "100% renewable energy", so it could probably be run a lot cheaper anyway.

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Anonymous Coward

Re: Desalination will never work...

Yes, but as some plotician (spelling intended) let slip yesterday, it is all about joining up the water companies with pipes and creating a market between them. They love markets. People unconnected with the supply of water will be able to make profits on the transactions and more money will be taken out of the system by these people than will be saved, with the bill payer left to make up the difference. If there is no crisis, you can't do that and all those vested interests have to be borne in mind when listening to the arguments.

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Anonymous Coward

Re: How dare you!

Nobody is stopping anyone washing cars or watering gardens.

You can do both without using a hosepipe, just as you can drink beer without pouring most of it down your shirt.

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Anonymous Coward

Re: Re: Desalination will never work... (@Jecko 10.05)

It's either another outbreak of lawyer's greed as you outline, OR from your first sentence: "... joining up the water companies ..." . My guess is that engineering a drought is the easiest way of regaining State monopoly power over water supply. Suits the Civil Service's pro EU ( and anti-Britain) agenda.

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Devil

Re: Desalination will never work...

re Matt Bryant's comment 'I do know that it was advertised that the Beckton plant runs on "100% renewable energy"...'

So that's why the plant only runs 10% - 40% of the time (or off altogether)!

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Boffin

Re: Desalination will never work...

Possibly, but if that is the case, then we need to note that the cost price of the leccy is presumably much lower than the standard rate, and should really be much,much lower - this is the ideal companion to wind power really.

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FAIL

Re: Desalination will never work... (@Jecko 10.05)

"Civil Service's pro EU ( and anti-Britain) agenda."

I actually LOLed.

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Re: Desalination will never work...

Good call... didn't even think of that!

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Why not use solar-powered evaporation?

To be honest, using electricity to provide desalinated water seems a poor second to using solar heat energy to purify water by evaporation and condensation.

Sure, you can always use electricity-powered desalination plants to "top-up" the supply, but base water demand should always be provided with sustainable energy - and the beauty of solar heat is that it already comes in the form required: There are no losses involved in converting it to a different type of energy - just focus it and use it.

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Silver badge

Re: Why not use solar-powered evaporation?

Looking outside the window now in search for enough solar energy to run the evaporators....

Nope, as expected - a totally futile undertaking.

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Re: Why not use solar-powered evaporation?

If you look outside your window at the moment, you might see something a bit like this

http://i.telegraph.co.uk/multimedia/archive/02208/london-piccadilly-_2208964k.jpg

and you might reasonably conclude that there isn't actually a water shortage at the moment, it is just in the wrong place.

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Anonymous Coward

Re: Why not use solar-powered evaporation?

Vladimir: I'm not sure where you are, but I can definitely see out of the window, with use of only sunlight, this kind of suggests that there is solar energy knocking about.

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Anonymous Coward

Re: Why not use solar-powered evaporation?

Evaporation would require a thousand times as much energy - and it would have to be re-condensed.

Osmosis is very cheap, and getting cheaper.

Pumping water is expensive in energy terms, a vertical rise of 100meters is equal in cost to pumping it 100km, desalination is a much more viable option at these sorts of distances.

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Re: Why not use solar-powered evaporation?

Because reverse osmosis is far more efficient a way to purify water than evaporation and condensation. The energy required to fully evaporate 1000L of water is on the order of 732 kWh (assuming the water starts at 10C). Yes you can get all that energy back when the water condense but you'd need 99.86% recovery efficiency to achieve the same energy usage as reverse osmosis.

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Holmes

Re: Why not use solar-powered evaporation?

Okay, we've shot the solar powered route down. Why not a combination of solar and wind ( would be popular with Register staffers, ha ha ha) ? Run the thing constantly, even out of drought and use it to top up aquifers and the water table.

Set up a few smaller plants along the estuary and leave them to keep working, then we'd have plenty of cheap water with less whining from the hand-wringers.

Well, it worked in Sim City 2000.

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Anonymous Coward

Surely it would require investment in both water production (desalination infrastructure) and water retention (pipe replacement) if your plan were to work in anything other than the very short term? It would be nonsensical to divert all investment away from pipe replacement projects and into desalination because the problems of water loss through leakage are only going to get worse, not better, leading to having to produce ever increasing amounts of potable water at ever increasing costs. A more sustainable model should be a balance of pipe replacement (which isn't really an ongoing cost) and water production investment (possibly in combination with reducing demand for water in the worst affected areas by dealing with the overcrowding in areas like the South-East).

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Happy

Hey Lewis, you missed something

Graphene - wonder material - water just gushes though it, leaving the salt behind.

The 7kWh/tonne figure might well be revisable to 700Wh/tonne. At this point do we really care about losses?

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Re: Hey Lewis, you missed something

You still have to pump the water through the graphene, or at the very least use gravity force.

When you add salt to water, it releases energy, therefore it must require energy to get the salt back out of the water otherwise you have the possibility of a perpetual motion machine.

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Re: Hey Lewis, you missed something

They missed something else, too! It's not like El Reg. to miss an opportunity for scantily clad women to appear (especially on the one occasion it would have been appropriate):

http://www.youtube.com/watch?v=WCKJWi_4jvA

Honestly, this is the first thing that the article made me think of!

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Re: Hey Lewis, you missed something

--When you add salt to water, it releases energy, therefore it must require energy to get the salt back out of the water otherwise you have the possibility of a perpetual motion machine.

Uhh yeah. As you yourself state, the graphene system uses pumps or 'gravity force'

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Re: Hey Lewis, you missed something

Tides?

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Re: Hey Lewis, you missed something

Actually, when you add salt to water, it absorbs energy - wikipedia says 3.88 kJ/mol. Hence the use of ice and salt to get minus 10, 20 degrees.

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xyz

as written by a water desalination plant salesman.

mmmmmm....stop showering 30 times a day

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Wind

Here's an idea. Wind power is great, but we can't store it so it goes to waist, as there's far less usage at night.

Why not have the desalination plants run off Wind power during the night, and turn off in the morning?

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Re: Wind

Yes, it could be great way to smooth out the load curve, not just for wind, but for solar, tidal and other generation. I'd have to run the numbers to be sure.

Beckton produces 150e6 litres a day = 150e3 tonnes per day.

7kWh/tonne means you need about 1e6 kWh/day

1e6/24 = 42MW power.

http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Demand/demand24.htm

Difference between day and night is about 13e6MW.

So, one plant reduces load curve variation by 0.3%. Hmmm, perhaps not. Corrections to my arithmetic anyone?

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Re: Wind

At the moment we very rarely have more wind power than we know what to do with. From memory it has happened twice in the last 5 years or so when we have had freak conditions. One of them was when the main Scotland <-> England power lines were blown down. Scotland was unable to export its surplus electricity to England and the windmills were running at maximum output due to the weather conditions so ended up being powered 100% by renewables for a few hours.

Generally what happens is that when the wind starts blowing, we switch off a few gas power stations and save the gas for when we do need it later on. Also, large hydro stations can be turned off, and we let the water build up behind the dam for later use.

Having said that, yes it is likely that desalination plants would be used when electricity demand is lowest, and the cheap electricity prices they would get from doing that would reduce the cost still further.

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Anonymous Coward

Re: Wind

I wondered why I was getting so fat in my old age, it must be all this wind power they do. I'll have to run some of it off overnight.

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Headmaster

Re: Wind

Wind doesn't go to waist, but beer certainly does.

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Re: Wind

It would indeed be great to be able to use wind power for desalination. This could reduce the adverse effects of having to accommodate fluctuations in power input by the grid and by mainstream generating plant. Reducing the impact of wind energy's variability would save on costs and improve the reliability and longevity of the rest of the system.

The problem is that wind only generates power for 30% of the time, so three times as many desalination plants would be required for a given output. Off-peak nuclear would have a greater duty cycle and is likely to be both less expensive and more dependable.

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Re: Wind

Actually what really happens is that in the morning the prices are set and loads are calculated. Power stations are told to come on or off on the schedules depending on their costs. If the weather is really windy the gas stations lower their costs so that they dont have to be knocked off. Then a price war erupts. Nuclear is generally very cheap anyway.

Its not as cut and dry as people think.

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Re: Wind

Your day night difference is out by 1000 - the difference is about 13-25 GW not TW.

But your 0.3% calculation is correct.

http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Demand/Demand8.htm

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JG Ballard and tilting at windmills.

Where does all the salt (and other waste) go? Presumably you have to ship it off and dump it a long, long way away. Yes, I have read JG Ballard's "The Drought".

Here's a greener scenario. If you ran the desalination plants at night to top up storage, you could use some of that wind generated energy which doesn't have much of a market at 3am in the morning.

Another alternative is to build a bloody big pipe from the north and west to the south and east!

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Anonymous Coward

Re: JG Ballard and tilting at windmills.

On your chips?

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Anonymous Coward

Re: JG Ballard and tilting at windmills.

@Your alternative: Only if it's charged at London prices.

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Re: JG Ballard and tilting at windmills.

"Another alternative is to build a bloody big pipe from the north and west to the south and east!"

A pipe isn't even required. There are plenty of canals or even rivers that could be used to do it perhaps with just a few small lengths of pipe to join up the gaps.

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Re: JG Ballard and tilting at windmills.

'Where does all the salt (and other waste) go? Presumably you have to ship it off and dump it a long, long way away. '

The process produces a more concentrated brine as waste product, so normally you just lay a long outfall pipe which discharges the effluent well away from the intake. Potentially tricky in an estuary where the tide pushes water upstream twice a day.

One cost Lewis has left out is that of filtering Thames water to a point where it can be sent to the osmotic membranes without clogging them up.

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Re: JG Ballard and tilting at windmills.

Just guessing here, from my days studying chemistry, but I would expect the plant to take brackish water and produce a stream of pure water, and a larger stream of more saline water. You'd have to site intakes and outlets with a bit of care, but is it any different in the end from taking more water out of the upper reaches of the Thames drainage system, and putting it through a set of kidney-filters?

Your point about using such things as a sink for surpluses of wind-generated energy is a good one. If the electricity demand can be quickly changed, it would help stabilise the system. But it might have to run in a steady state.

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Devil

Re: JG Ballard and tilting at windmills.

Oi!! Get off our water!... Divert some of your sun our way through giant glass mirrors IN SPACE, and then we'll give you some water.

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Re: JG Ballard and tilting at windmills.

"Here's a greener scenario. If you ran the desalination plants at night to top up storage, you could use some of that wind generated energy which doesn't have much of a market at 3am in the morning."

That would work nicely for nuclear as well.

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Re: JG Ballard and tilting at windmills.

"Another alternative is to build a bloody big pipe from the north and west to the south and east!"

You've already got one!!!

It was built during the war to ship petrol around the country. Clean it out and use that to ship water around the place. Dunno whether it's big enough to do the job, but it should help.

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Re: JG Ballard and tilting at windmills.

"Another alternative is to build a bloody big pipe from the north and west to the south and east!"

They are called "aqueducts" and the Romans built some hundreds of miles long, a few of which are still standing nearly 2000 years later. How far is it from Wales (the land of perpetual rain) to South-East England?

Of course, maybe 21st-century technology isn't up to copying what the Romans did...

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Re: JG Ballard and tilting at windmills.

Gradients are the problem. There are plenty of these - look at how manchester gets its water (from the lakes). Liverpool gets some from wales too.

However, it isnt as simple as building lots of pipes.

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Alert

Re: JG Ballard and tilting at windmills.

@ Tom Welsh

Hey bugger off! The English already flooded several valleys so you could steal our water to feed Brum and Scouseland. You're not having any more unless you can figure out a way of directing some more of that sun you get in the South East our way! As someone else suggested above maybe a giant mirror in space or something. But we are definate on this, no sun, no water! ;-)

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Paris Hilton

Math error

The interestingness of this article is to some extent destoyed by Lewis' repeated insistence that 10kWh per 1,000 litres translates to 1kWh per 167 litres. If he just used the honest approach of rounding up 1.67kWh to 2kWh, it would hardly damage his point, but it would make it seem less like he's fiddling the numbers to suit his case.

Paris, because she can't divide 10,000 by 1,000 either.

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(Written by Reg staff) Silver badge

Re: Math error

I think your maths are wrong. Show your working, please.

7kWh to process 1000 litres. 0.007kWh per litre. 167 litres per person per day. 1.169kWh per person per day.

Or as Lewis put it "approximately 1 kWh per day".

C.

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Coat

Re: Math error

@diodesign. I think your English is wrong. Maths is a singular noun. Sorry, couldn't stop myself. Coat, gone.

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