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Case Studies

Dundee City Council and SWARCO

Two energy storage systems optimising an EV charging hub for both fleet and public use with on-site renewable energy generation

  • Industry:  Local Authority
  • System no:  2
  • Power:  600kW
  • Capacity:  720kWh
  • Application:  Renewable energy storage, EV charging
  • Functionality:  Site decarbonisation, energy resilience, managing peak load demands


Dundee City Council is a pioneer in electric vehicle (EV) adoption and has won multiple awards for its work in this field. The authority has electrified 25% of its fleet and eliminated all grey fleet car usage thanks to investing in 60 electric pool cars.

It has also recently started replacing its diesel vans with EVs and its electric fleet also covers refuse vehicles, an electric sweeper and two minibuses.

The council previously worked with Connected Energy to provide a battery energy storage system (BESS) at its Princes Street EV charging hub. Based on the successful project, the authority wished to include two further systems for its new hubs at the Clepington Road depot.

This site was home to the UK’s first rapid charger and the council wanted to expand on its initial charging points by creating two substantial hubs here – one with public access, and the other solely for the council’s own fleet.

The Brief

Dundee City Council was looking for an energy storage solution to support its plans for new EV charging hubs.

The Council’s Clepington Road depot is home to 210 vans, operated by its construction division. It was a former coal storage site for the railway and had been the main fuelling depot for petrol, diesel and gas oil vehicles. It had also traditionally acted as a fuelling location to provide extra resilience for the ambulance service.

It was with this resilience in mind that the Council wanted to include battery energy storage in the new hub – to ensure that the site was able to meet the growing demand for electricity that would be required.

We wanted to make the best possible use of Clepington Road, which meant a charging hub for the council’s van fleet, but also a hub for public use. When developing infrastructure on this scale it was crucial that we included an element of renewable generation and energy storage. Our fleet includes emergency call-out vehicles, and it is essential that they are always fully charged. Battery energy storage provides the additional resilience that we need.

Fraser Crichton, Corporate Fleet Operations Manage, Dundee City Council

The Solution

Connected Energy installed two E-STOR systems, one at each of the hubs. In both cases, the E-STOR is configured to manage peak loads, ensuring that the hubs do not exceed their import capacity.

The E-STOR is programmed to monitor the grid load, and when demand from the vehicles plugged into the hub gets close to exceeding the power available from the grid, E-STOR kicks in to bridge the gap. Both hubs include solar PV, so the BESS is configured to store solar energy for charging vehicles later.

It also provides additional power as needed during periods of high demand. Integrating E-STOR with both a solar PV array and the grid ensures that the site optimises its use of renewable energy, providing cost savings and environmental benefits. In addition, the E-STOR provides energy resilience as a reservoir of power for use with mission-critical vehicles during any grid supply issues.

The system will also help the council to reduce their electricity costs from the outset. From their experience with Princes Street, the Council has calculated that the inclusion of battery energy storage has reduced their energy costs by 2p per kW to 15p per kW. With 130 charging sessions a day expected across the three hubs, the whole life costs become a substantial saving to the council.

Next Steps

Deploying two E-STOR systems supported the council in installing 58 fast chargers plus a bank of 100kW and 150kW rapid chargers.

The future for Dundee is to investigate V2G. With the number of vans located at the depot, the holistic picture is to use those vans to the benefit of the building, powered by solar throughout the day and the battery at night and using any available electricity throughout the day to support the building’s own power.

Battery energy storage systems provide us with a practical, proven and cost-effective route to expanding our EV charging infrastructure. As grid demand grows and more second life batteries become available, battery energy storage can provide an answer to both energy challenges. Connected Energy has the ideal solution.

Fraser Crichton, Corporate Fleet Operations Manager, Dundee City Council

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