Use Case: Caledonia - Utilizing bus depot for public charging


With global attention focused on Glasgow in 2021 for the COP26 climate summit, First Bus and the Scottish government were keen to demonstrate a practical approach to decarbonizing public transport and improving air quality.

Upgrading public transport infrastructure is central to achieving net-zero climate goals. However, diesel buses are a major source of roadside air pollution, mainly in the form of nitrogen oxides (NOx), as well as producing carbon emissions. In a study, Glasgow found that buses and coaches were responsible for 70% of NOx emissions on one city center street.

To address the problem, Glasgow introduced a Low Emission Zone (LEZ) for scheduled bus services in 2018 and continues to progressively reduce emissions. While the LEZ doesn’t require bus operators to adopt electric vehicles, First Bus has outlined an ambition to be emission-free by 2035. As a Scottish company, partnering with officials in Glasgow presented an obvious opportunity to prove the concept.

While electric buses are a good solution both in terms of climate commitments and roadside air pollution, cost was a major concern as it was important that public transport in Glasgow remains affordable. It was also important for First Bus, which is one of the UK’s biggest bus operators, to develop an electrification solution that made commercial sense and could be scaled across its fleet.

The requirements of the First Bus Caledonia Bus Depot in Glasgow are typical of many bus operations in the UK and elsewhere in the world — all the buses are out servicing their routes during the day and need to be charged overnight. This means the facility needs to be able to charge a large number of e-buses simultaneously and ensure that all the vehicles have sufficient charge to complete their routes by the time they set off in the morning.

From a commercial perspective, it was critical to optimize the use of such a large charging facility. With buses out on their routes all day, the depot would be sitting idle most of the time. Being able to partner with other businesses that could use the charging infrastructure during the day was therefore an important goal.


To meet these challenges, Heliox worked with First Bus to design and install the UK’s biggest fast-charging depot, capable of simultaneously charging 162 vehicles with a total installed power of 12MW. The Caledonia Bus Depot was completed in 2022 and comprises 80 Rapid 150 kW modular chargers (160 DC outlets) and two Mobile 40 kW chargers (two outlets).

This delivers enough power to fully charge each bus in less than four hours, providing plenty of flexibility for Heliox’s smart-charging solution to draw down electricity from the national grid in the most cost-effective way.

To allow the depot to charge commercial fleet customers during the day, the chargers include easy-to-use payment touchscreens and were designed to allow optimal charging for all vehicles — from large trucks to passenger cars. With this flexibility, the Caledonia depot has been designed as a fast-charging hub that optimizes the infrastructure investment, while also helping the transition of Glasgow’s delivery vans and taxis to electric power. It’s a win-win for the city and First Bus.


The Caledonia Bus Depot has been hailed by the city’s leaders as a “game changer”. Shortly after the project was completed, First Bus announced a commercial partnership with DPD, Europe’s biggest delivery network.

DPD has described the facility as “fantastic” and said the shared-use model is a “really smart initiative”. The agreement gives DPD drivers access to fast, reliable and secure charging in the heart of the city, allowing them to travel further afield while making deliveries.

After an initial trial period, DPD plans to expand its use of the Caledonia site to support its entire fleet of electric vans in Glasgow, which is planned to total 200 by the end of 2023, allowing DPD to offer EV-only deliveries in the city.

Nationwide, DPD aims to be the most sustainable parcel delivery company in the UK and is on track to have 4,000 EVs on the road in 2023.

First Bus now plans to expand the Caledonia depot further with theconstruction of a new substation that will supply enough power for an extra 200charging points.

Indeed, thesuccess of the Caledonia Bus Depot has proven that large fast-chargingfacilities are ready to be rolled out across the country to meet needs of bothpublic transport providers and commercial fleet managers.

First Bus is already planning to add more electric buses across the UK, including at another depot in Glasgow and in Aberdeen, as well as in five other cities in England, as it moves towards its goal of an entirely zero-emission fleet.

Talk to a Heliox EV Charging ExpertDownload our electric truck report
Share this post
Download our electric truck report
No items found.
Share this post

Stay in the loop

Provide your email to be notified about new blog posts

Subscribe to our blog