Depot Charging Costs and Constraints
What actually drives the price, and how to budget for depot charging infrastructure without nasty surprises.
Key Takeaways
- •Grid and civils account for 50-80% of total project cost. Charger hardware is rarely the expensive part.
- •Get a DNO quote early. It's free to apply and tells you the real cost of power.
- •Phase your rollout: install infrastructure capacity upfront, deploy chargers as needed.
- •Budget 5-10% of capital cost annually for electricity, maintenance, and software.
In this guide
What Actually Drives Cost
Most people focus on charger prices when budgeting for depot charging. That's a mistake. The charger hardware is often 20-40% of total project cost. The rest is grid, civils, and installation.
Grid Capacity and DNO Process
If your site needs more power than currently available, the DNO must upgrade the connection. This can involve new cables, transformers, or even substations. Costs: £10k-£500k+. Timeline: 6-18 months.
Civils and Trenching
Getting cables from the supply point to the chargers means digging. Tarmac, concrete, distance, and ground conditions all affect cost. £200-£500 per metre for standard trenching is typical.
Charger Count and Power Mix
More chargers = more cost, but not linearly. Bulk purchasing brings discounts. The power split matters: 7kW AC chargers cost £500-£1,500. 50kW DC chargers cost £15k-£40k.
Load Management and Smart Charging
Smart charging software can reduce peak demand by 30-50%, potentially avoiding expensive grid upgrades. Software costs £10-£50/charger/month but can save tens of thousands in infrastructure.
Cost Breakdown by Category
Here's a realistic breakdown for a typical 20-vehicle depot charging installation:
| Category | Low Estimate | High Estimate | Notes |
|---|---|---|---|
| DNO/Grid upgrade | £0 | £200,000 | Depends entirely on existing capacity |
| Civils and groundworks | £15,000 | £80,000 | Distance and ground conditions |
| Charger hardware (20x 7kW) | £15,000 | £30,000 | £750-£1,500 per unit |
| Installation and commissioning | £10,000 | £25,000 | Electrician and testing costs |
| Project management | £5,000 | £15,000 | Often underestimated |
| Total | £45,000 | £350,000 | 8x variance is normal |
Notice the range. An 8x difference between low and high is not unusual. The only way to narrow it down is to get actual quotes, starting with the DNO application.
Phasing Your Rollout
Smart operators don't install everything at once. Here's a better approach:
Phase 1: Future-proof the infrastructure
Install cabling, switchgear, and civils for your full eventual capacity. This costs more upfront but avoids re-digging later. Include spare capacity in your DNO application.
Phase 2: Deploy chargers to match vehicles
Only install chargers as you take delivery of EVs. Charger technology improves rapidly. Delaying deployment means better hardware at lower prices.
Phase 3: Add faster charging as needed
Start with slower chargers where dwell time allows. Add DC fast chargers later for specific use cases (rapid turnaround, opportunity charging).
Frequently Asked Questions
What's a realistic budget for depot charging infrastructure?
For a 20-30 vehicle depot, expect £150k-£500k all-in, depending on grid requirements. Smaller sites (5-10 vehicles) might manage £30k-£100k if grid capacity exists. Larger sites (100+ vehicles) can easily exceed £1m. The variance is driven almost entirely by grid and civils, not charger hardware.
How much does a DNO upgrade actually cost?
DNO costs are notoriously unpredictable. Minor upgrades might be £10k-£30k. Major upgrades requiring new substations or cable runs can be £100k-£500k+. The only way to know is to apply and get a formal quote, which itself takes 3-6 months.
Should we install fewer fast chargers or more slow chargers?
Depends on dwell time. If vehicles are parked 8+ hours overnight, 7kW chargers are more cost-effective. For shorter dwell times or multi-shift operations, faster chargers (22kW-50kW) are necessary despite higher costs. Many depots use a mix.
What ongoing costs should we budget for?
Electricity is the obvious one, typically 15-25p/kWh for business rates. Add £100-£500 per charger per year for maintenance contracts. Software/backend fees vary widely: £0-£50 per charger per month. Budget 5-10% of capital cost annually for operations.
Can we phase the rollout to spread costs?
Yes, and you should. Install infrastructure (cabling, switchgear) for future capacity, but only deploy chargers as needed. This avoids over-investing in hardware that may become obsolete, while protecting against future groundwork costs.
What grants are available?
In the UK, the Workplace Charging Scheme offers up to £350 per socket (max 40 sockets). Some local authorities have additional schemes. For fleets, the landscape changes frequently, so check current availability before budgeting.
About Mark Pymm
Mark has spent 15+ years in the EV charging industry, leading teams that have delivered over 100,000 charge point installations. He advises CPOs, fleets, installers, and investors on strategy, delivery, and go-to-market. His approach is practical, not theoretical.
Learn more about Mark →Get a realistic cost estimate
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