You wouldn’t guess it from its cloudy skies or lush parks and gardens, but London in recent years has become a water-stressed city. The city suffered a drought four years ago that brought water rationing to some of its neighborhoods, and its old system of pipes that date back to Victorian times are not helping its water problem.
Last week city officials, led by Prince Philip, flipped the switch on a £270 million (US$390 million) desalination plant. Built by Thames Water, the plant will only operate when London’s usual sources of water fall short. Fueled by biodiesel, the plant will transform salty water from the River Thames into drinking water using a reverse osmosis method. Thames Water officials brag that the water is so pure that calcium and other minerals have to be added in order for it to taste like water from the tap.
The project is not without controversy. Former London Mayor Ken Livingston sued Thames Water as far back as 2005 to prevent the project, claiming that any resulting carbon emissions were not worth the resulting clean water. According to Livingston, London’s real water problem was the city’s aging infrastructure, coupled with the lack of water meters that in turn give residents no incentive to curb their water usage. Boris Johnson, who took the mayor’s office after Livingston in 2008, agreed to drop the challenge after some environmental concessions, and city officials insist that project is necessary as London is expected to add 700,000 more people by 2021.
But while Thames Water claims the desalination plant will only run off of used cooking oil, that claim is dubious. The reverse osmosis process used at the London plant will require twice as much energy as required by conventional desalination methods. True, the result is a yield of 85% drinking water; older forms of desalination, such as what Middle East plants incorporate, have only a 50% yield. But all those fish and chips eateries aside, it’s a stretch to believe that enough biodiesel exists to fuel a plant that in the long run is expected to provide water to as many as 580,000 homes. If weather patterns continue, this stand-by operation may very well start filtering water full-time.
In an ideal world, desalination plants powered by alternative fuels would solve the earth’s growing water crisis. But the reality will probably be different: a patchwork of desalination plants like London’s; increased metering; a development of drought-resistant crops; a massive investment in water infrastructure that currently politicians would rather not address; and finally, a pricing of water that matches economic reality instead being provided to residents, farmers, and businesses for practically free.