Renewable energy company Dulas has announced the completion of the second of two large new hydropower plants at Bryn Cowlyd water treatment works in North Wales for Dwr Cymru Welsh Water (DCWW).

The 200kW hydropower plant which Dulas designed was installed in a custom-made structure housing one of two break pressure tanks to reduce the build-up of water pressure on the raw water feed. DCWW now has two reliable sources of hydropower in a mountainous and relatively isolated location, which are integrated into the existing local water infrastructure.

The new plant comprises a turbine, generator and hydro control cabinets, as well as instrumentation and hydraulic valves. Following construction, it was connected to the grid by means of a buried HV cable, and to the raw water mains via an underground branch pipework system, thus ensuring a continuous supply of water from the nearby Llyn Cowlyd Reservoir to the water treatment works in the valley below.

Unlike run-of-river schemes, the level of discharge from the new hydro has to reflect Cowlyd WTW's operational requirements. The hydro control system works in parallel with float operated valves in the break pressure tanks to respond to fluctuating demand at the works. Should the hydro fail or require maintenance, any excess water is automatically routed through a bypass system to the works. This ensures an absolutely reliable and secure supply of potable water into the distribution network.

“Construction of the hydropower plant posed a number of technical, logistical and environmental challenges,” commented Crispin Angood, Senior Project Manager at Dulas. “As a result, we’re very pleased with what we’ve achieved at Bryn Cowlyd. The hydroplant will provide consistent financial benefits and, as Welsh Water is a not-for-profit company, these will be re-invested into the business – helping to give value for money to consumers.”

In its 2010 energy policy statement, the Welsh Government aimed to have a total of 22.5GW of installed energy from renewable sources by 2025. Hydropower has long been the second biggest contributor to Welsh renewable energy generation, but installation has stalled since recent changes to the feed-in tariff subsidy payment.

Dulas also provides 12MW of operation and maintenance work across 16 sites for DCWW.

Photo of hydropower pump house at Bryn Cowlyd WTW courtesy of Dulas.