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NI Water’s first Battery Energy Storage System installed at Ballykelly Wastewater Plant

29 November 2022 12:49

Ballykelly WwTW Battery  | NI Water News

NI Water recently completed a project at the new Ballykelly Wastewater Treatment Works (WwTW) to situate a new solar panel system. This system has now been upgraded with the addition of NI Water’s first battery energy storage system, which has now been switched on! This battery system is the first of its kind for NI Water.

Last year, NI Water announced the completion of the overall £5million investment to upgrade Ballykelly WwTW, providing a new wastewater treatment approach, utilising reed beds as part of the treatment process, providing a natural, long-term and resilient solution. The Ballykelly plant is leading the way with this sustainable solution to wastewater treatment, which maximises the use of renewables as part of an integrated solution. This new battery energy storage system will further enhance the efficiency of the plant through increased use of solar energy.

Mark Brownlee NI Water Senior Capital Project Manager said:

“The aim of the new battery system is to enable the plant to operate using 100% locally generated solar power for as much of the year as possible. In winter months, during periods of lower solar generation, the battery system can be topped up from the grid using off-peak cheaper energy tariffs.

“This innovative system, which was developed in-house, is the first of its kind for NI Water and will bring many efficiency benefits and cost savings to the company in light of rising energy prices.”

The battery system will be used in an innovative way to drive costs down during high demand periods in the winter by maximising the use of both the electricity network and the Solar Panel System. Energy can be stored and released flexibly to reduce costs during peak periods and decrease the demand on the grid.

The Ballykelly Wastewater Treatment Works has already scooped a 2022 International Green Apple Environment Award and was recently named as “Infrastructure Project of the Year” at the 2022 CEF Construction Excellence Awards earlier this month. 


Notes to editors:

The combined energy system now active at Ballykelly WwTW involves:

  • Solar Panel system size: 240 solar panels (91.2kWp) connected through 75kW PV inverters.
  • Lithium battery energy storage system size: 134 kWh battery storage with 75 kW battery inverter.
  • Backup diesel electric generator.

For further information, please email

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