Hydropower energy recovery at Blackstairs GWS (Co. Wexford)

A visit to the water intake location by the Dŵr Uisce team on 11/01/2018.

A visit to the water intake location by the Dŵr Uisce team on 11/01/2018.

The terminal part of the pipeline leading water from the intake into the raw water tank.

The terminal part of the pipeline leading water from the intake into the raw water tank.

Context

The Blackstairs Group Water Scheme is a gravity-fed system supplied by a main reservoir located on the east face of Blackstairs Mountain, Co Wexford. It provides drinking water to 1037 households with a global average demand of 1500 m3/day. The piping system has an approximate total length of 117 km with diameters ranging from 50 to 150 mm.

Proposed system

A previous investigation from the Dŵr Uisce project identified a significant potential for energy recovery on the water supply line leading into the raw water storage tank within the premises of the treatment works operated by EPS Group.

Such potential could most conveniently be exploited by installing a centrifugal Pump As Turbine (PAT) in the terminal section of the pipeline.  A design flow rate and head of 15 l/s and 40 m respectively were selected, leading to an expected power output of around 4 kVA. The PAT design algorithm being developed at Trinity College Dublin as part of Dŵr Uisce research project has been applied on the selected site, and helped identifying the ideal characteristics of the main PAT and generator set to be chosen.

If operated 24-h all year round such device would produce about 25-37,000 kWh of clean renewable electricity worth over 4-6,000€ and reduce the energy consumption of the treatment works by 20-25%.

Project timeline

A collaboration between the Dŵr Uisce project, the Blackstairs GWS and EPS Group has been established with the aim of building the energy recovery installation by the beginning of 2019. As of late April 2019 the scheme is fully operational.

The terminal part of the pipeline leading water from the intake on entering the tank itself.

The terminal part of the pipeline leading water from the intake on entering the tank itself.

View of the turbine during commissioning.

View of the turbine during commissioning.