Desalination - a necessary evil?

The government's approval of a £200M desalination plant in east London highlights its failure to secure the sustainable use of resources, writes CIWEM's executive director Nick Reeves

London mayor Ken Livingstone's big idea is to make London genuinely green and sustainable, and a blueprint for all other cities around the world.

After a recent visit to China, with leaders of other UK cities, he was inspired by plans to build Dongtan, which will be the world's first eco-city - with very few cars, no waste and everything (including water) recycled.

So, Ken will be livid his vision for London has taken a hit. Certain green groups will say that ministers are reneging on their commitment to the environment and to sustainability. That the government - following a public inquiry - has given the go ahead to a £200M desalination plant at Beckton in east London, when the mayor rejected the plans, will raise again questions about how best to supply London with water without harming the environment.

Ken will see it as an attempt to frustrate his plans to turn London green, raising the political issue of who controls London and its water. So, he may yet appeal against the decision. But I suspect he will just have to swallow his pride and acknowledge that he has been trumped this time. The controversial desalination plant involves drawing water from the ebb tide of the River Thames, which is about two thirds less salty than sea water. The flow will be pushed at high pressure through reverse osmosis filters to provide up to 140Ml of drinking water each day, enough for a million people. Construction is due to begin next year, and the plant should be fully operational in 2009.

Essential weapon

It will only be used during periods of extreme drought, long periods of very low rainfall or in the event of problems at existing water treatment plants. Desalination will now become an essential weapon in Thames Water's armoury to secure water supplies for London in the face of climate change, growing consumer demand, population growth and plans for more housing across the South-east of England (see editor's comment page 3).

Alongside action on leakage, the likelihood of a new reservoir in Oxfordshire and the possibility of mandatory water meters, desalination measures will guarantee water for London whatever climate change may bring and whatever the level of consumer demand.

Desalination plants require a lot of energy and have a large carbon footprint. So, what does this mean for the environment? And will the government's support for desalination confuse an already sceptical public on politicians' stated commitment to reducing greenhouse gas (GHG) emissions and tackling a changing climate?

Recent research shows 45% of the public still believe that the jury is still out on the science of climate change, and hence they are unwilling to do their bit to reduce their carbon footprint until the case is proven. So, it seems that the answer to that question of public confusion is a resounding yes - which is alarming.

Before and during the public inquiry, critics of the desalination plans for Beckton argued that carbon emissions from the energy-hungry plant would be too high and go against a government-declared commitment to reducing GHGs, and send out the wrong message to the public. It is alleged the plant will pump out around 250,000 tonnes of GHGs each year and relatively little water. This is roughly the same level of pollution as 8,000 cars. And there are no guarantees that some of the water will not leak into the ground before it gets to our homes.

And the irony of the government supporting an energy-guzzling solution to the threat of water scarcity which is caused by climate change has not been lost on some. For sure, desalination has had a bad press. This is not just because of the energy and the GHGs. But it is because some policy wonks regard it as a knee-jerk, quick-fix solution to a problem that could better be solved through more effective water demand management, public awareness campaigns on the value of water, more investment on water leakage and the creation of a Water Savings Trust.

But, with the government hardwired to more and more development and to more and more housing for a growing population, Thames Water must do its duty and supply water to its customers. And it must find solutions to secure supplies now at a time of unprecedented climatic and social change.

To say that it has been caught between a rock and a hard place is to understate the challenge. And, while Thames Water cannot be criticised for trying to meet its legal obligations to its customers and the requirements of regulators, the government can be blamed and must accept criticism for trying to face both ways, and for ignoring the fact that population times consumption equals impact.

Be less profligate

Opponents of desalination are right to point out the priority to reduce leakage. And they are correct to say that the public must be less profligate with water. The point of the desalination plant, though, is not to provide a substitute for conventional water supply, reservoirs and the possibility of meters in every home. It is a back-up in times of severe drought and threat to supplies.

Action on demand management, metering and better public awareness should have happened years ago, alongside the post-war drive for economic growth. It did not. And successive governments failed to invest in the infrastructure for water or take predictions on climate change seriously enough soon enough.

So, we are where we are, and there will be no retreat - any time soon - on plans for growth for London and the South-east. So, in the face of the political realities, desalination - as a routine measure for water supply - has a certain inevitability about it. But we will soon see the social and environmental consequences of a lack of political foresight and leadership, and regret the day that all post-war governments failed to understand the need for a cohesive approach to securing a sustainable future.

In a sense, the battle for a desalination plant at Beckton has not been about the plant itself but a much more fundamental issue of how - without further breaching environmental limits that have already been breached - we also provide the essentials for life and economic growth. This is a battle of ideologies, and water merely the battleground.

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