Scottish Water taps into demand for electricity

The company is poised to become an energy provider using turbines in its pipes

Mark Horne

Scottish Water is to generate green electricity by fitting turbines in mains water pipes, in a revolutionary scheme that it claims could slash bills and provide energy for thousands of homes.
The publicly owned utility is to launch a pilot scheme in Fife later this year, which will produce renewable energy by harnessing the power of water flowing at high pressure underground.
The aqua-turbine system, which was developed by Norwegian scientists to power offshore oil and gas rigs, will be fitted at one of its plants in Glenrothes. The device will generate enough electricity to power about 50 homes.
Although the Difgen turbine will cost around £100,000 to install, it is expected to produce £20,000 worth of energy every year.
If the trial is a success, Scottish Water intends to install the turbines at its water treatment plants across the country. Larger individual turbines could potentially produce enough electricity to power more than 200 homes.
“The first trial will demonstrate whether the reality meets the theory, and we will use the data to look at further opportunities across the rest of our network,” said Grant Nairn, Scottish Water’s director of technology and innovation.
“The device that we intend to fit at Glenrothes promises to generate around 60kW of power — enough to power around 50 homes — which we could either feed into our own plant or hook back into the grid.”
Nairn said the turbines would also reduce leaks and lower operating costs, which would be passed on to consumers in the form of lower bills.
“The device has the dual benefits of generating electricity from the flow of water in our mains pipes as well as allowing us to control the pressure in those pipes,” said Nairn.
“This is a very useful feature in our ongoing battle against leakage and wastage. In the long term, this promises to benefit customers through lower bills, and it also contributes towards Scotland meeting its carbon reduction commitments.”
Ash Gupta, who is promoting the technology in the UK for the Norwegian manufacturer Zeropex, said the science behind the scheme was simple.
“Water can travel underground at the sort of pressure that would blast the taps off,” he said. “This device has a brake which steps that pressure down and is connected to a turbine which spins and generates power. It kicks out at least 60kW of clean, green energy 24 hours a day, 365 days a year.”
The Stavanger-based firm showcased the technology at an oil industry exhibition in Aberdeen last year.
“Scottish Water are going to be the first out of the blocks to use it this way,” said Gupta.
“But we are also now talking to a number of other utility firms, including Severn Trent and Northumbrian Water in England.”
The UK government-funded Carbon Trust, which helps and advises companies on cutting energy waste, confirmed that it is interested in the Difgen scheme.