National Express, Coventry
In 2021, National Express, part of Mobico Group, was awarded funding from the UK Government’s Department for Transport as part of Coventry’s successful bid in the All-Electric Bus City scheme.
Introduction
Following a competitive tender, Zenobē was named as Principal Contractor to deliver end-to-end electrification of the operator’s depot, one of the largest projects of its kind to be executed in the UK.
This was also the UK’s largest ever single electric vehicle bus fleet transaction, helping the operator lead the way in the transition to a zero-emission fleet.
Project overview
Zenobē’s full, turn-key solution for National Express to electrify their Coventry depot includes:
Design and build of the charging infrastructure including the installation of 140 Zerova chargers to support 140 fully electric ADL/BYD E400EV buses, including all associated civils work and HV engineering
Installation of network metering for smart charging and power load management into the depot
Installation of 193kWp solar PV array, optimised by a 1.2MWh stationary second life battery
A 16-year ‘electric-transport-as-a-service’ (ETAAS) contract that removes risk by providing management and financing of the on-board batteries for the lifespan of the bus, full vehicle funding arrangements and financing, and operation and maintenance of the charging infrastructure, all for a monthly fee.
Challenges
Project scale – At the time of inception, the project was one of the largest electric bus projects proposed in the UK. This presented Zenobē and National Express with new design and delivery challenges, including the risk of considerable losses across the low voltage (LV) cable network within the depot. Long LV cable runs are not only costly but are inefficient when transferring large volumes of power.
Minimising energy costs – One of the key outcomes identified by the operator was the need to minimise energy costs and power the new fleet in the most cost-efficient way.
Power supply optimisation– The depot would need to substantially boost its power supply so it could safely charge a full fleet of electric buses.
Solutions
Zenobē delivered the project on-time including long-term financing and operational guarantees of the fleet and infrastructure, so the operator can continue to focus on delivering for their customer and day-to-day operations.
Private high-voltage network – The sheer scale of the site immediately highlighted the risk of considerable losses across the low voltage (LV) cable network in the depot. To address this, Zenobē developed an on-site, private high voltage (HV) network, better suited to the needs of the charging infrastructure.
Building an on-site micro-grid – To minimise costs, Zenobē developed a system of on-site generation for National Express, utilising vacant space on the depot’s roof to install 193kWp of solar PV panels. The solar PV panels are connected to a Zenobē Energyskid, a second life stationary battery made from refurbished electric bus batteries. This created an on-site microgrid, with solar power transferred to the Energyskid where it is stored and used for charging during the more expensive energy tariff periods. to create an on-site microgrid
The combination of on-site generation, optimised power load management and Zenobē’s software provided the operator with the ability to charge their vehicles at the lowest possible cost.
Power supply optimisation – In addition to the on-side generation, Zenobē installed two transformers, oversized relative to the grid. These in combination with a power load management system enabled optimal spread of power across the site.
Results
Zenobē’s work electrifying National Express’s flagship Coventry depot achieved a significant number of milestones not only for the two businesses, but for the development and financing of fully electric bus fleets in the UK. These include:
The largest single electric bus transition in the UK, with 130 fully electric bus vehicles secured in one transaction for National Express
First micro-grid of its kind with integrated solar PV arrays, interfacing with a second life battery storage to be installed in a bus depot in the UK
First on-site battery made from second life bus batteries to be installed in a bus depot in Europe
First Electric-Transport-as-a-Service contract in the UK electric bus sector guaranteeing National Express daily access to a ready to use electric bus fleet
“The support from the Zenobē tech sales team has been very beneficial for us in ensuring we get the depot layout right and also where we locate various parts of the infrastructure. Zenobē have helped National Express along on our electric journey.” – Tom Berry, Fleet Decarbonisation Manager, Mobico Group
In numbers
battery-electric ADL/BYD vehicles financed
year Electric-transport-as-a-service (ETaaS) contract
Zerova chargers installed
of on-site second life battery storage for optimal power usage
solar PV array
