Scottish Water has completed work on a £2.3 million solar power and battery energy storage scheme which is set to save around 169 tonnes of carbon annually.

Howden PV scheme arial view

The scheme, at Howden Water Treatment Works near Selkirk, consists of 2,112 ground-mounted solar panels and 15 racks of batteries to store the power generated – which will meet over a third of the site’s power usage and support Scottish Water’s drive to reach net zero emissions by 2040.

The battery energy storage system, the first of its kind on a Scottish water treatment asset and only the second on a Scottish Water site to date, means 100 per cent of the renewable power generated by the scheme can be used on site whenever it is needed.

It has been led by Scottish Water Horizons, the public utility’s commercial subsidiary, and delivered by renewable energy specialists Emtec Energy.

Scottish Water Horizons Project Manager Alan Mearns said:

“This scheme will generate 1.2 megawatts of green electricity, providing just under 35% of the annual electricity needed to power the site and will make a massive difference to the carbon footprint of the treatment works.

“Thanks to the inclusion of the batteries as part of the scheme we have been able maximise the potential of the site to generate renewable energy – the size of the land meant we were able to install a large number of solar panels, and the batteries then allow us to store and use 100 per cent of it on site as we need it, rather than having to export it to the grid.

“As the scheme is remotely monitored, at the time of year when there’s not a lot of sunshine, it allows us to import from the grid at a lower rate to charge the batteries and then feed it back into the works during the times when it costs more, helping to reduce operational costs.”

Recognising the importance of safety in such an innovative project, rigorous measures were implemented including remote fault detection, automatic shutdown systems and fire suppression within the battery cabinets.

Scottish Water Operations Team Leader Mick Jones said:

“This water treatment works is responsible for providing water to our customers in Selkirk and the surrounding area and runs 24 hours a day to ensure we can provide that service round the clock. It is a huge user of electricity and this scheme is a great way to offset some of that usage.

“Scottish Water has a lot of ground area that can be utilised to support renewable technologies in this way and the inclusion of the battery as part of this project meant we can capture all that solar power and provide a permanent feed of electricity, rather than having loads of power when the sun shines and nothing when the sun’s down.”

Chris Clark, Director at Emtec Energy, added:

"The solar and battery energy storage system at Howden represents a significant achievement for Emtec Energy and underscores our dedication to pushing the boundaries of renewable energy solutions.

“We have delivered a complex, high-efficiency system that not only meets the stringent requirements of the site but also aligns with our vision of reducing carbon footprints across Scotland.”

The energy needed to provide essential water and waste water services makes Scottish Water the largest single user of electricity in the country. This latest investment means the site joins a growing list of water and waste water treatment works are now either self-sufficient or partly sufficient in their power requirements.