The first associations one makes with London's weather are gray, overcast days interrupted by regular rainfall, but rarely a ray of sunshine. But in spite of the copious moisture an English day can bring with it, the British metropolis is actually starting to parch. Its booming population and climbing temperatures mean the city of eight million is facing a looming water shortage.

To meet the coming need, London's German-owned water utility, Thames Water, is investing €300 million ($369 million) to construct the city's first desalination plant. The facility, to be situated in the East London borough of Newham, will take brackish water from the river and convert it into drinking water.

According to Thames Water, demand for water in London has increased by 15 percent over the last two decades and that growth looks set to continue. It is predicted that the city's population will grow by 800,000 people by 2016. In addition, rising levels of affluence and a growing trend toward single households in the city are pushing water usage up, while warmer temperatures are keeping precipitation levels down.

"These are the major challenges we're having to grapple with," Nick Tennant, a spokesman for the utility, told DW-WORLD. "In the mid-term, we need this desalination plant to make sure we can meet with the peak demand times, especially during the summers or drought periods."

Although it might be counterintuitive, because London and England's southeast has such a high population density, the region actually gets less rainfall per head than much drier cities like Madrid or Istanbul. London uses 55 percent of its available rainfall for public consumption. Further west in Wales, on the other hand, only 8 percent is used.

Thames Water's new plant, expected to be up and running around summer 2008, will have a capacity to desalinate 150 million liters per day and provide water for nearly 900,000 people. It will be based on the principle of reverse osmosis, which involves forcing water through a membrane to remove salts and other impurities.

Supplying a Drier Continent

Desalination is a well-established technology for urban water supplies although most capacity is concentrated in the Middle East, where skyrocketing population levels, little rainfall and the depletion of groundwater resources have forced the regions to turn to the ocean for their drinking water supplies. The desalination market is a growing one, expected to generate expenditures of $95 billion (€77 billion) from 2005 - 2015, again, mostly in the Middle East.

However, several European countries besides England have turned to desalination technologies to get water to where it is needed. Southern European countries, such as Turkey, and the Turkish section of Cyprus are perennially plagued by water shortages and they have put desalination facilities online.

The island of Malta (photo) has very limited fresh water resources and is increasingly reliant on desalting processing to provide residents with their daily liquid needs. Gibraltar, on the southern tip of Spain uses natural and manmade catchments to gather rainwater, but depends on its desalination plant for its drinking water needs.

Further north on the peninsula, Madrid has recently decided to build about 20 desalination plants on its east coat to provide water for its parched southeast, shelving an earlier controversial plan that would have piped water from the Ebro River in the wetter north. The region already has Europe's biggest reverse osmosis desalination plant, which is owned by a subsidiary of Thames Water.

Growing popularity, falling prices

Desalination plants are increasingly popular with water-starved regions because they can be less environmentally intrusive than running large pipelines across hundreds of kilometers of land. Diverting water from rivers and other bodies of water can also impact sensitive ecosystems.

Just ten years ago, desalinated water would have cost much more than treated river water, for example. But desalination technology has improved while the cost of treating surface water has increased. That trend is continuing -- the price to turn salt water fresh is falling some 4 percent annually.

Desalinated water is still more expensive than normally treated water, which is why the treatment is not an option for many poorer countries. Thames Water said it will likely raise its water prices by €2.25 a week to cover the added costs.

Next page: Environmental groups say desalination avoids the real problem -- overconsumption

But environmental groups warn against viewing desalination plants as the ideal solution to meeting current and future global water needs. They are expensive to build and consume a great deal of energy.

"They might be useful for some concrete solutions in some parts of the world," Guido Schmidt, head of the Living Waters Program at Spain's WWF environmental group, told DW-WORLD. His group has welcomed the decision to go the desalination route rather than divert water.

"But we don't consider them a worldwide solution," he added. "We need to look at problems of over-exploitation and conservation as well."

Some worry that as prices for desalination continue to fall, and as the technology improves, plants will spring up like weeds, drawing attention away from the core issue of how to handle a limited natural resource like water.

Britain's Environmental Agency, a regulatory body, is already sitting on between six and eight applications from water companies to build new plants there, according to Phil Bursten, a senior water policy officer with the UK's RSPB wildlife conservation organization.

"[Water utilities] are using environmental resources in an inefficient way," he told DW-WORLD. "We have to ask if these plans are really the sensible way to go forward. We have more of a problem with efficiency than with supply."

Necessary for the future

But Nick Tennant of Thames Water says conservation programs will not be enough to meet future needs. He noted that the Thames region only got 56 percent of its normal rainfall in June, indicating the arrival of another dry summer. Regarding accusations of waste and inefficiency, he countered that the utility is working to renew London's notoriously leaky underground pipes, one-third of which date back to the Victorian age, and increasing efforts to get the conservation message out.

"But we don't want to preach water misery," he said. "Life is meant to be enjoyed."

For an increasing number of regions, that enjoyment is going to be helped along by desalination plants. On Spain's east coast, the new processing facilities will likely provide water for a planned tourist development with a price tag in the billions, which is largely based on new, green golf courses. This new Florida in Spain, as the marketers like to call it, is one very thirsty creation.