Siphon-fed hydroplant installed at Whiteadder Reservoir

The Whiteadder hydro energy generation scheme will enable Scottish Water to generate electricity while controlling the level of the reservoir during seasonal fluctuations in weather without the need for major civil engineering works.

Fed by a siphon, it is believed to be the first of its type in Europe.

The £3m investment will enable the siphon technology to draw water up though the intake and over the top of the dam which then runs down through the siphon, through the hydro turbine, and back to the environment.

The electricity generated will be used to offset 30% of the power used by one of East Lothian’s largest pumping stations, named Hungry Snout. This pumping station takes 32 million litres of water per day to Castle Moffat water treatment works, which supplies most of the East Lothian region.

Neil Beaumont, hydro energy senior project manager at Scottish Water Horizons, the public utility’s commercial subsidiary that is delivering the scheme, said:  “This is a unique project to work on. Due to fluctuating seasonal conditions in Scotland, the flows at Whiteadder Reservoir vary from 150 to 1,200 litres per second so it was important that we could measure and control the reservoir levels accurately as its primary function is to provide water to customers.

“In collaboration with renewable energy experts Aecom and Ossberger, we selected equipment that could accurately measure water levels even during adverse weather conditions using smart controls and sensors which will ensure we are not taking too much water from the reservoir.”

Scottish Water’s contractor was Emtec Energy.

The investment at Whiteadder is expected to generate 0.82GWh of renewable energy per year from the 199kW turbine.

Gordon Reid, Scottish Water’s general manager for net zero, said: “Scottish Water owns the most reservoirs in the UK, and we are always looking for opportunities to produce renewable power and make the most of these assets. We already have over 30 hydro turbines installed on our assets, and the use of this novel technology is an exciting development for Scottish Water. As a business, we have made some bold and ambitious commitments to reduce our carbon emissions, and I believe this technology will help us deliver on those ambitions.”

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