Tapping into energy from water mains
Posted: Tuesday 19th June 2007
New technology with the potential to provide enough power to meet the needs of approximately 7,000 homes – or to illuminate 45EiffelTowers– could soon be operational in the UK.
The technology – which was recently successfully trialled in Stamford, Connecticut, USA – works by installing intelligent 'micro-turbines' in existing water and wastewater mains, where there is a measurable difference in pressure and available flow. Each turbine is capable of generating several kilowatts of energy and early estimates suggest that it can initially be installed in 100 sites in the UK, providing enough energy to boil the water for 24,000 cups of tea every hour.
Pressure energy is an essential element of water distribution and is required to circulate water through distribution systems, ensuring that customers at all topographical elevations receive a consistent water supply. On all distribution networks there are instances, typically on downhill gradients, where pressure needs to be reduced using pressure reducing valves (PRVs). The micro-turbines are designed to sit upstream of PRVs and turn this lost energy into energy.
The venture, which has the backing of UK Trade & Investment, has prompted the launch of Rentricity Limited – a new company dedicated to delivering the clean energy potential of the technology to the UK water industry, which has been created by UK support services company Mouchel Parkman and US energy recovery company Rentricity Inc.
"The concept of water mains turbines has been around for a while although the technology which supports it is new and proven," explains George Taylor, managing director of Rentricity Ltd. "It's an extremely exciting development given escalating energy prices and the increasing demands on business and society to devise alternative energy sources. This technology will allow water companies to retrieve and capitalise on a resource that would otherwise be lost to them."
Unlike wind power, the turbines are also contained within chambers that are generally below ground. "In the vast majority of cases there will be little or no aesthetic impact on the surrounding landscape," explains George.
Several leading water companies – including Anglian Water, Northumbrian Water, Severn Trent Water, Yorkshire Water and United Utilities – have already expressed a keen interest and a number are currently considering further feasibility work following initial presentations.
"Other organisations – including British Waterways, the Carbon Trust, and New and Renewable Energy Centre (NaREC) – have also expressed interest and we believe that the technology can also be transferred to similar sized gas mains," adds George.
