How politicians could end droughts FOREVER: But they don't want to
They'd rather ration your water than do some simple sums
Analysis 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 in the street may be required next year.
And yet, astonishingly, it would require only a small investment - far less than has been spent on fixing leaky pipes in recent years - to render the capital's water supplies completely and utterly drought-proof, forever. All the fresh, drinkable water the city's population requires for its taps, its showers and its hosepipes could be produced without taking a drop from rivers, aquifers or reservoirs, at minimal cost and with only a tiny impact on energy use and carbon emissions.
In short, Britons' water is being needlessly rationed in a staggeringly pointless effort to limit energy consumption and carbon emissions by a very small amount - a move driven, as is so very normal, by a political (and civil service) agenda which seems completely divorced from the hard numbers surrounding the issue.
Londoners vote tomorrow in the capital's mayoral elections, but both candidates, it seems, would rather prepare people for more stringent rationing (to the point of poor hygiene and serious health risks) than make any attempt to sort matters out once and for all.
Here are the hard numbers in a nutshell, using London as a case study for the whole of the UK - and indeed the entire developed world.
Average normal water consumption by the capital's 8 million people is 167 litres per person per day: just to be clear, this includes the use of hosepipes for watering gardens, washing vehicles etc. Almost all of this water at the moment is taken from rivers or extracted from groundwater. These supplies are finite and depend ultimately on rainfall. As the city's population has grown, it has gradually become the case that they may not cope with demand during prolonged dry spells.
But modern technology can be used to cheaply turn seawater, the supply of which is effectively infinite, into fresh drinking water by desalinating it. Alone among British water companies London's Thames Water does actually possess a single desalination plant, at Beckton on the Thames Estuary, but this only has the capacity to produce 150 million litres a day - less than 10 per cent of the city's requirements - and it is run at low output or completely shut down most of the time.
In general, desalinating seawater in a modern reverse-osmosis plant like Beckton requires the use of 7 kilowatt-hours (kWh or "units" on your electricity bill) of electrical energy to produce a tonne (1,000 litres) of drinking water. In fact, Beckton requires significantly less energy than this as estuarine water is not as salty as seawater proper, but this article is meant for a wider audience than just Londoners, so let's assume 7 kWh/tonne to begin with.
In order to make all the water a person requires, then, a desalination plant needs approximately 1 kWh per day. A kilowatt-hour, purchased on the wholesale electricity markets, can generally be obtained for six pence or less at the moment: the necessary energy would cost a water company say £22 per person annually.
Total electricity cost for a whole year's water supply from the sea, London wide? About £176m, less than Thames Water's profit margin even in hard times; much less when the company is doing well. And of course in reality there would be no need to use desalination for the entire supply (this would actually cause flooding1). Also, in reality, we are speaking of brackish water not brine. So we can see that using desalination to make London drought-proof would cost very little.
But what about capital investment? Maybe desalination plants are really expensive. Maybe that's why we only have one proper one in the whole of the UK, and why we are so often told there's a drought on and we must expect hardships.
Nope: Beckton cost just £270m to build. Another 15 such plants - enough to provide London's entire water supply if required - would cost approximately £4bn, an investment of just £500 for each person living in the city. Enough desalination plants to provide half the supply, which would make the city completely drought-proof for the foreseeable future, could have been built for less money than Thames Water has spent reducing leaks in the last nine years - and the leaks programme, while highly disruptive to the city as roads have been torn up in order to replace old pipes, has delivered only comparatively minor water savings.
So that's the reality of water supply and modern technology. For a trivial cost, we can make all the fresh water we need out of seawater.
So it's really very plain that there's no possible excuse for ever imposing standpipes or hosepipe bans or any other form of water rationing on Londoners or indeed anyone else - certainly anybody who lives in a developed nation within reach of the sea (the great majority of the human race lives near the sea or tidal estuaries connected to it). Modern reverse-osmosis technology means that we can use small amounts of energy to make as much fresh drinking water as we want, and the costs are small enough that the resulting water is too cheap to meter. Running an oven for an hour or two, remember, consumes enough energy to make an entire tonne of water.
And yet here we are in the year 2012, in one of the planet's greatest and richest cities, with water rationing in force and worse rationing being foretold. What on Earth is going on?
Briefly, politics is going on. The former London mayor, Ken Livingstone, virulently opposed the building of the Beckton desalination plant. His successor, the extrovert bicycling media-tart Boris Johnson, allowed Beckton to go ahead. Yet it is still official London government policy under his administration that "desalination is considered an emergency measure and is not a long-term solution for future supply needs".
This picture is echoed nationally, with the head of water at the Environment Agency telling the BBC that "you don't want to rely on desalination".