Work is underway by Scottish Water Horizons on a GBP 2 million ($2.7m) solar and battery storage in southeast Scotland, Kallanish reports.

The project calls for 1 megawatt of solar with 2,520 solar panels adjacent to Perth’s sewage treatment plant, to be installed by Scotland-based Absolute Solar and Wind. That system will be connected to four vanadium flow batteries capable of storing up to 0.8 megawatt-hours of energy. They will be provided by Invinity Energy Systems.

The solar and battery storage are expected to go into service in 2021.

The project is the largest single solar investment announced by Scottish Water, a publicly traded water company, and its commercial subsidiary, Scottish Water Horizons. It is also the first Scottish Water solar project to include battery storage.

The renewable energy generated by the project is expected to produce about 25% of the electricity needed to treat the waste water. By adding battery storage, that means that 94% of the renewable energy generated will be used on site with the flow batteries charging from the solar electricity.

The sewage plant will reduce its carbon footprint by about 160 tonnes/year and plant energy costs by about 40%.

“This project represents an exciting step forward in our work towards Scottish Water’s ambitious goal of achieving net zero carbon emissions by 2040,” says Scottish Water Horizons business development manager Donald MacBrayne in a statement.

The project also includes an electric vehicle charging station to support Perth and its fleet of 1,600 municipal vehicles shifting away from fossil fuels. Perth wants to be known as the most sustainable small city in Europe.

Scottish Water Horizons has developed 46 solar and 20 wind projects along with two biomass projects and a waste water heat recovery project.