Fleet Depot Solar & EV Charging
Depot electrification is the defining energy project of UK logistics this decade — and the depots winning it treat charging, generation and grid capacity as one design problem solved from the vehicle rota outwards.
Start from the rota, not the vehicle count
Twenty electric vans does not mean twenty chargers. It means a schedule: which vehicles are parked when, how much energy each needs by departure, and which dwell windows overlap. A last-mile operation with staggered runs may serve 20 vans on 12 managed sockets; a single-shift trade fleet parked 18:00–07:00 needs more sockets but enjoys an enormous charging window that 7kW fills easily. Every depot design we produce starts as a parking-and-energy timetable — the hardware list falls out of it, never the other way round. Socket strategy and hardware selection then follow the charger guide logic at fleet duty-cycle grade.
The supply capacity strategy
Depot supplies were sized for lighting, conveyors and a kettle — not for a fleet's worth of fuel delivered electrically. The wrong response is reflexively buying a bigger connection. The right sequence: measure the real half-hourly headroom; apply dynamic load management to fit charging inside it (three to five times nameplate arithmetic, on most sites); buffer genuinely immovable peaks with storage where the spread justifies it; and only then procure DNO works for the gap that engineering cannot close. Combined solar-and-charging projects make one DNO engagement cover generation and load — and a managed, flattened profile is a materially easier application than a naïve one.
Where solar fits the depot picture
Depot roofs are big, and depot energy appetite is bigger: the classic constraint inverts, and most depots can absorb everything their roof generates. Daytime-dwell fleets charge directly on the generation curve via solar-following control; overnight fleets still bank the building load displacement and the export-to-charging conversion at weekends. Typical configurations: 100–250kW rooftop for van depots, 250–500kW+ where chilled storage or workshops add load, with canopies extending capacity over parking where roofs run out. At 5–8p/kWh lifetime cost, depot solar is the cheapest fleet fuel either of us will ever price — the business case page stacks it against the 60–85p public rapid alternative.
Van scale, mixed scale, HGV scale
Vans (now): mature vehicles, 7kW-dominant charging, WCS-supported sockets, paybacks driven by avoided public charging. This is the phase with no excuse for waiting. Mixed fleets (now–2028): add selective 22kW and a DC unit for mid-shift turnarounds; load management becomes non-negotiable as simultaneity rises. eHGVs (planning horizon): per-bay demands of 150–350kW+ change the infrastructure class entirely — likely dedicated supply works, possible private HV assets, certainly land-use planning. The depots that will transition fastest are the ones whose van-phase civils — duct sizing, board provisioning, DNO strategy — were drawn with the truck phase on the same sheet.
The operational payoff
A finished depot runs quietly: vehicles plug in on return, the controller fills them against departure times using the cheapest available electrons, the dashboard reports solar share and pence-per-mile by vehicle, and drivers stop queueing at public rapids on company time. Fuel cost per mile typically falls 60–75% against public charging and the operational hours recovered are a second saving nobody models but every transport manager notices. It starts with the rota and twelve months of half-hourly data — the quote form takes both.
Fleet depot questions
Our DNO says the depot supply can't take fleet charging — is that the end?
Almost never. The first response is engineering, not copper: dynamic load management spreads charging across dwell windows and typically multiplies viable socket count three to five times within the existing supply. The escalation ladder runs scheduling, then battery buffering of peaks, then a supply upgrade as the last resort — and a flattened, managed demand profile makes the DNO conversation easier even when an upgrade is genuinely needed.
How much of a depot fleet's energy can solar realistically cover?
For daytime-dwell fleets (last-mile vans returning between runs, multi-shift operations), 30–60% across the year. For strictly overnight-charging fleets, solar covers the building load and exports unless a battery shifts it — usually 10–25% of vehicle energy, improving where weekend dwell absorbs generation. The honest number comes from the rota, which is why we model from your actual schedules.
What does depot electrification cost at van scale?
A representative 20-van depot: 12–16 managed 7kW sockets, dynamic load controller, civils, plus 100kW rooftop solar — £150,000–£220,000 combined in 2026, before the WCS grant (£350/socket) and year-one tax relief. Against it: 20 vans × 18,000 miles on depot solar-plus-grid instead of public charging saves £60,000–£80,000 a year at current rates. Depot projects are unusual in this sector: the fuel saving, not the energy saving, drives the case.
Should we wait until the HGV transition is clearer before investing?
Build the van phase now and provision for the truck phase: duct routes sized for DC, board space, land allocation for future supply infrastructure, and a DNO application strategy that reserves the path. eHGV charging needs (150–350kW+ per bay) dwarf van requirements and will likely justify their own supply works — but a depot that ducted and planned at van stage retrofits years faster and cheaper than one that didn't.