Depot Charging Scheme reopening risks backing wrong infrastructure unless operators start with operational needs

The reopening of the Depot Charging Scheme will inevitably trigger another round of conversations about chargers, batteries and grid connections. But before any of those conversations get too far, fleet operators should ask a more basic question: what does this depot actually need to do?

I think there is a risk that electrification projects are being designed backwards. Operators decide how many electric vehicles they expect to run, look at the infrastructure available to support them and then work out what can be funded. And while this may produce a perfectly credible application for grant support, it does not necessarily produce the right depot.

For instance, a charger that qualifies for funding is not automatically the right charger. The same applies to battery storage, grid upgrades and the rest of the infrastructure that sits behind an electric fleet. Sure, public funding can improve the economics of a project, but it cannot compensate for poor design. That’s why the starting point has to be the operation.

Take two fleets with the same number of electric vehicles as an example. One has vans returning gradually from 4pm onwards, with most parked until the following morning. Another has trucks arriving within a tight two-hour window and needing to be ready to leave again before dawn. On paper, both might appear to need the same number of charge points, but in practice, their energy requirements are completely different.

Operators need to carefully consider vehicle duty cycles, return-to-depot times and daily energy consumption, but also how much charging demand is likely to coincide. That then has to be considered alongside the electrical demand already on site and the capacity available from the grid. None of this is particularly glamorous, but it is what determines whether the finished depot actually works.

It also exposes one of the weaknesses in thinking about electrification primarily as a vehicle replacement programme. Diesel allowed fleets to treat energy and vehicles as largely separate purchasing decisions because the infrastructure was already there and refuelling took minutes. However, electrification removes that separation.

Once a meaningful proportion of the fleet is electric, decisions about vehicles have direct consequences for the site’s power requirements and vice versa. A change in route length, shift pattern or vehicle utilisation can alter the charging requirement, while a constraint on available power can influence how many vehicles can be charged, when they can charge and potentially even which vehicles are suitable for the job.

Next, there is the question of growth. Infrastructure designed around the first five electric vehicles may look sensible in year one and distinctly short-sighted by year three. If the direction of travel is towards 20 or 30 vehicles, it makes little sense to ignore that simply because the immediate requirement is smaller.

That does not mean overbuilding from day one. It does, however, mean knowing where the fleet is heading and making decisions now that do not unnecessarily restrict the next phase.

Battery storage is a good case in point for this approach. It can be useful where grid capacity is constrained, where demand is concentrated into particular charging windows or where greater control over when energy is drawn from the network has value. But it is not a universal answer, any more than a higher-powered charger is automatically better than a lower-powered one. Once again, its value depends on the depot.

This matters particularly when grant funding is available. Schemes understandably focus attention on what expenditure is eligible, but eligibility and suitability are two different things. The danger is that the funding framework starts to shape the technical solution rather than supporting a solution that has already been derived from the operational requirement.

With the next Depot Charging Scheme window soon to open, fleet operators would be better served by reversing that process. First, look in detail at the vehicles, routes, dwell times, energy demand, site constraints and likely growth. Only then can you decide what infrastructure is required, and funding comes after that.

The fleets that make this transition successfully will not necessarily be those that install the most charging hardware or secure the largest grant. They will be the ones that treat electrification as an operational energy challenge from the outset.

 Mark Duxbury, UK director, iwell