Connected Energy powers up Nottingham City Council depot

Nottingham City Council has the ambition to become the first carbon neutral city in the country with a target of 2028. This means that the city council is a front runner in the transition to electric vehicles. To support this ambition, the council was awarded funding through Interreg Europe with a contribution from Innovate UK, to transform the main municipal depot at Eastcroft just outside the city centre.

The depot is home to a fleet of 250 electric fleet vehicles including six new electric bin lorries, as well as being the main waste disposal depot with an incinerator and recycling on site. The aim of the project was to transform the site’s energy use through the introduction of new technologies – all with the aim of reducing carbon and energy costs.

Steve Cornes, principal energy projects officer at Nottingham City Council, said: “Our main aim is to reduce the carbon intensity of the operations on site. Projects such as this are critical as we work towards becoming carbon neutral by 2028 and this will demonstrate what is possible, both for the city council itself but for similar buildings throughout the UK.”

The project set out to demonstrate how an energy system can be created which integrates 40 vehicle-to-grid bi-directional chargers – one of the largest installations to date in the country – with three solar arrays with a combined generation of 138kWp and a battery energy storage solution.

The brief was to supply, install and operate a 600kW system, and all associated maintenance, at the depot which would be used to store and redistribute the energy generated on-site. The system objectives also included arbitrage and providing services to the grid. Nottingham City Council wanted to be able to respond to the ongoing evolution in the grid services market with a system that had the flexibility to be controlled and used for the best service at any given time.

All technologies were required to be interoperable with an overarching energy management software solution that would operate multiple devices to increase the efficiency in the supply of renewable energy.

Cornes continued: “As the city council fleet transitions to electric vehicles, including large vehicles such as refuse lorries, we will be using the battery energy storage system to prop up the grid. By using intelligently managed BESS and V2G, the use of on-site solar energy can be maximised, and the depot will effectively be able to isolate itself from the grid during peak periods and avoid peak tariffs.”

The solution involves two of Connected Energy’s 300kW systems being installed on-site. The systems will support the site in two main ways. They will act as a store for the energy generated from the solar and vehicle to grid technology, allowing these technologies to charge the batteries which will then be used directly to power the site. This will allow the site to reduce energy costs by reducing demand at a time of peak tariffs. The council’s preference is to use as much as possible on site however the battery energy storage system will also support the council to trade excess energy back into the grid.

Secondly, with extensive electric vehicle charging infrastructure on-site, including the bin lorries which required charging at 80kW, the system will be used to prop up the grid and provide power to the charge points to support load balancing. The battery energy storage working with solar PV also allows the site to maximise the use of renewable energy to decarbonise the charging of the fleet of EVs.

Cornes said: “The systems will allow us to ensure production costs of electricity will be negligible, allowing us to peak shave so that we can avoid high electricity tariffs and give us the opportunity to trade electricity back to the grid.”