An ABB industrial drive, ACS800, is helping produce up to 100 MWh of energy for Welsh Water as part of a pressure control system at its Pen y Cefn water treatment works. This accounts for some 10 percent of power demand at the site.
The ABB drive forms part of a pressure and flow control system supplied by Zeropex, a specialist manufacturer of water turbines. Known as the Difgen, the system also recovers energy from water pressure in pipelines.
Within the Difgen, a turbine resists the incoming water, controlling its flow. The turbine turns the generator, which produces power that is synchronised to the grid supply by the 37 kW variable-speed drive.
As part of Welsh Water’s programme to reduce costs, there is always a focus on identifying potential energy savings. Hydro turbines are one such potential saving opportunity as they use a head of water and a flow, which provide an ideal opportunity to generate power to meet on-site demands.
The Pen y Cefn water treatment works is gravity fed with raw water at a pressure of up to 11 bar from a nearby storage reservoir. Water is fed into an open dissolved oxygen flotation tank, so this pressure is no longer required for the process. Previously this pressure would have been removed through a pressure reduction valve.
Welsh Water asked Zeropex to look at the site and recommend a hydro turbine that could be used in the pipelines. The requirements were to provide highly accurate control of flow or pressure, with a smooth operation that would avoid any water hammer or surges. Zeropex identified the site as ideal for installation of its Difgen pressure control system.
Duncan Collins of Zeropex says: “The ABB drive is an integral part of this system, providing excellent control. We use ABB drives in our products because the company has an excellent reputation within the UK water industry. They also have supplier agreements with most water companies, meaning that our control systems meet the required electrical standards. ABB offers an excellent after-sales support structure and replacement parts are readily available. ABB drives have been used in all our European installations to date.”
ABB (www.abb.com) is a leader in power and automation technologies that enable utility, industry, and transport and infrastructure customers to improve their performance while lowering environmental impact. The ABB Group of companies operates in roughly 100 countries and employs about 140,000 people.