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Cardiff Bus

In 2021, Cardiff Bus was granted funding from the UK Government’s Ultra-Low Emissions Scheme. This funding, in addition to Cardiff Bus’s own investment, enabled the operator to purchase 36 battery electric Yutong E12s from supplier, Pelican Bus & Coach.

A first for Cardiff Bus

This was the first time Cardiff Bus had purchased any electric buses and would now need the supporting charging infrastructure to power them. The operator’s depot was of course designed to meet the needs of its longstanding fleet of diesel vehicles, including the depot’s connection to the local electricity grid which was not sufficient to meet the higher demand associated with fleet EV charging.  


To ensure the transition was executed in a cost-effective way while avoiding significant impact to its day-to-day operations, Cardiff Bus engaged with Zenobē, entrusting us as the principal design and build contractor for the project.  

Zenobē as Principal Contractor

Due to the scale of what was the operator’s first fleet and depot electrification project, we developed an end-to-end charging solution for Cardiff Bus, including 15-year ‘as-a-service’ support of the charging infrastructure. By bringing our all-encompassing fleet electrification expertise to the project, Cardiff Bus was able to concentrate on their day-to-day operations while the build took place.


We managed all civil works and developing a solid foundation to enable the next stage of electrical installation, including the installation of charger bases, trenching for HV/LV cables and plinths to support a new low voltage (LV) panel and transformer.


Grid-connection upgrade and financing and installation of charging infrastructure

One of the key challenges faced by the project team was the requirement to upgrade the existing grid-connection. Without this, the depot would simply not be able to manage the amount of power needed to charge the fleet of e-buses sufficiently.


However, upgrading a grid connection is an expensive process. For Cardiff Bus to overcome this upfront cost, we developed a tailored financing solution to pay for the upgrading works and managed the process with the local Distribution Network Operator (DNO), at the time Western Power Distribution and now known as National Grid.


With a sufficient grid connection now in place, the next stage of the process was to install the hardware and software technologies into depot. Following the laying down of cabling, a 2MVA transformer and accompanying LV panel were installed. These are crucial to manage the increased level of power the depot’s internal electricity network would now need to manage to support fleet charging. 10Hz power meters were also installed to monitor the level of power delivered to each charger. 


A site controller was also integrated into the infrastructure, this converts the ‘dumb’ chargers into a depot full of ‘smart’ chargers, allowing us and the operator to smart charge the vehicles and manage power load into the facility.


In addition to the financing of the grid-connection upgrade, we also provided financing of all charging infrastructure.


Charging infrastructure installed

Smart charging and Power Purchase Agreement (PPA)

We also provided a Power Purchase Agreement (PPA) to Cardiff Bus. A PPA is an agreement to facilitate the sale of electricity between the supplier and the end user, in this case between Zenobē and Cardiff Bus. 


PPAs reduce costs for the end user by offering long-term, short-term, variable or fixed billing agreements that are tailored to their site and charging requirements.


The bespoke Power Purchase Agreement combined with our integrated smart charging software, enabled Cardiff Bus to control charging and maximise the use of cheaper night-time tariffs, minimising monthly energy bills.


By appointing Zenobē as Principal Contractor on the civil and electrical engineering works, Cardiff Bus could concentrate on delivering for their customers.


The partnership continues beyond the design and build phase, with Zenobē also providing a 15-year ‘as-a-service’ support of the charging infrastructure, providing comfort that our expertise will be available for years to come, including ongoing smart software charging upgrades and power load management.


Our financing of the grid connection and the charging infrastructure also allowed Cardiff Bus to direct grant funding away from the infrastructure and into getting more fully electric buses on the road.


36 battery-electric Yutong E12 buses supported

In numbers


battery-electric Yutong E12 buses supported 


dual-gun Zerova 120kW chargers financed and installed


year ‘as-a-service’ operational responsibility from Zenobē

Peter Smith

Head of Product

Pete leads Zenobē’s growing team of Product specialists across all areas of the business. His team oversee our R&D as well as product development in both hardware and software.


He has been working in the European E-Mobility sector from over ten years, specialising in the design, build and delivery of software systems for EV Charging.