We costed a 50-van switch to electric. The finance director cried (in a good way).

A finance director we worked with last quarter has a spreadsheet on her laptop with 14 tabs, 3,200 rows and one increasingly weary comment in cell B47: "ask Mark about depot chargers". The spreadsheet is supposed to tell her whether switching 50 diesel Transit Customs to electric makes financial sense. It has been on her laptop for eleven months.

She's not stupid. She's not lazy. She's the second-best finance director we've ever met. The reason the spreadsheet has been sitting there for eleven months is that nobody has handed her a model she can actually defend to the board. So we built one. Headline numbers first: a 50-van switch from Ford Transit Custom diesel to Ford E-Transit Custom saves £1.6m in cash over five years, against a net capex of £126k for depot infrastructure (after the Depot Charging Scheme), with vehicles on a five-year contract hire at £370k a year. Payback inside year two. Residual-value risk hedged. BIK savings for the ops team layered on top.

The villain in this story isn't diesel. It isn't HMRC. It isn't even your DNO. It's spreadsheet fatigue — the slow-motion paralysis that happens when every CFO knows EVs save money but nobody hands them the actual model.

We're going to hand you the model.

The four cost lines every fleet TCO miscalculates

Most diesel-vs-EV comparisons come from a vendor with skin in the game. They show you fuel savings, wave at maintenance, and stop. The four lines that get miscalculated, every time:

1. Fuel — but properly modelled. Diesel at the pump in 2026 sits around £1.48/litre for commercial accounts post-rebate. A Transit Custom diesel doing 22,000 miles a year at 32mpg costs you £4,750 per van per year in fuel. An E-Transit Custom on a commercial overnight tariff at 14p/kWh, at 2.7 miles/kWh, costs £1,140 per van per year. That's not the saving anyone publishes — they use forecourt rapid prices to make the saving look smaller, or pence-per-kWh dreams to make it look larger. £3,610 per van per year is the honest middle.

2. Maintenance. A diesel van averages £820 a year in routine maintenance plus brake wear, DPF regens, AdBlue and the inevitable EGR. An equivalent E-Transit Custom comes in at £340 a year. Brakes last twice as long. There's no DPF, no AdBlue, no clutch, no cambelt. Servicing intervals stretch. Most fleet managers underestimate this saving by half.

3. Capital allowances. Electric vans qualify for the 100% First Year Allowance under HMRC's Plant and Machinery rules — extended in successive Finance Acts since April 2021 and currently confirmed through to April 2026. On a £28,000 E-Transit Custom that's a £7,000 tax deduction in the year of purchase at 25% corporation tax. On 50 of them, that's £350,000 of tax relief, year one. Most lease structures pass this benefit through; ask explicitly.

4. Residual value. Here's the one that gets ignored. Diesel van residuals are forecast by every major leasing house to decline 18-26% faster than current curves between 2027 and 2030 as the ZEV Mandate bites and used buyers price in a 2035 ICE phase-out. A 2026 diesel Transit Custom bought today is a depreciating asset in a softening market. A 2026 E-Transit Custom is a depreciating asset in a tightening one. Your lease company is already pricing this in — that's part of why electric monthly rates have converged with diesel.

The depot infrastructure cost stack

This is the bit the vehicle salesperson glosses past. Vans need somewhere to charge, and that somewhere has costs.

For a 50-van depot using 22kW AC overnight charging on a typical industrial three-phase supply, expect:

• Chargers: 50 × 22kW twin AC units (one socket per van), commercial OCPP back-office — £2,200–£3,400 per socket installed
• Switchgear and distribution: new sub-board, protection, metering — £18,000–£32,000
• Civils: trenching, ducting, cable runs to bays, bollards, line-marking — £45,000–£75,000 at this scale
• Monitoring and load management software: £150–£300 per charger per year ongoing
• DNO application (G99) and any reinforcement: £0 if there's headroom, up to £180,000 if there isn't
• Cost per bay all-in at this scale: £2,800–£4,200

For our 50-van site, with a healthy existing supply and no major reinforcement, the depot infrastructure lands at £180,000. The Depot Charging Scheme (run by Energy Saving Trust on behalf of DfT) currently funds 75% of infrastructure costs up to £1m for eligible operators — bringing this to a net £126,000. Apply before procurement, not after. They will not retro-fund.

The 5-year cash model

Here is the model the finance director's spreadsheet should have been doing.

Capex / lease (5 years):

• Vehicle contract hire: 50 vans × £7,400/year × 5 years = £1,850,000
• Depot infrastructure (net of DCS grant): £126,000
• FYA tax saving on £126k depot capex at 25%: £31,500
• Net cost of capability: £1,944,500

Opex saved (5 years):

• Fuel: £4,750 → £1,140 per van per year. Saving £3,610 × 50 vans × 5 years = £902,500

• Plus diesel price inflation hedge (modest 4% p.a. delta): ~£225,000

• Total fuel saving: ~£1,128,000

• Maintenance: £820 → £340 per van per year. Saving £480 × 50 vans × 5 years = £120,000

• Plus reduced VOR (vehicles off road) time — typically 1.8 days/yr diesel vs 0.6 days/yr EV. Productivity uplift conservatively £360,000 over 5 years for a 50-van delivery fleet.

• Total maintenance + uptime saving: ~£480,000

Headline 5-year cash saving on opex: ~£1.6m

Net position over 5 years vs running the diesel fleet:

• Diesel fleet equivalent total cost over 5 years (lease + fuel + maintenance + admin): ~£3.55m
• Electric fleet total cost (lease + net infra + fuel + maintenance): ~£2.65m
• Net 5-year saving: ~£900,000 on a TCO basis. £1.6m on cash opex alone.

Plus residual-value protection — if diesel residuals soften 22% more than EV residuals over the 2027-2030 window (consistent with current forecaster consensus), the lease company has already priced that into your diesel rate. You're paying for the cliff whether you switch or not.

Salary sacrifice — the bit your ops team will ask about

Once the depot chargers are in, the ops staff who use vans personally — supervisors, regional managers, anyone with a take-home — are going to ask. With BIK on electric company vehicles sitting at 3% for the 2026/27 tax year (rising 1% a year to 7% by 2030/31), a £45,000 electric car on salary sacrifice costs a 40% taxpayer roughly £420 a month net versus a £610 personal lease. The employer NI saving funds the admin.

You don't need a separate platform. Most fleet leasing partners now bolt salary sacrifice on as a wrapper around existing contract hire. Worth modelling separately, because it's pure margin uplift on a switch you were doing anyway.

Financing options, ranked for a 50-van switch

1. Contract hire (operating lease). Cleanest balance sheet treatment under IFRS 16 if structured as a service. Monthly rate includes maintenance. Residual risk sits with the leasing company. Best for: fleets that want predictability and don't want to own.
2. Finance Contract Hire (FCH). You get a lower monthly rate but take residual risk. Suits operators with strong used-vehicle remarketing capability.
3. Hire purchase. You own the asset, claim 100% FYA, balance sheet shows the kit. Best for: cash-rich operators wanting to maximise capital allowances.
4. Outright purchase. Maximum tax efficiency, maximum residual risk. Best for: small fleets or asset-rich operators with appetite to hold and remarket.
5. PPA / charging-as-a-service for the depot. Some operators wrap the £126k infrastructure into a per-kWh-delivered charge from a third party. Lowest capex, lowest control, often most expensive over 10 years.

What to model before you commit

1. Real route data, not manufacturer range. Pull six months of telematics. Calculate worst-case daily mileage per van. Pad it 15%. That's your battery sizing.
2. Depot supply headroom. Get your DNO quote in week one. Not week six. A G99 application takes up to 65 working days for complex cases.
3. Charging behaviour scenarios. Model 100% overnight, 80/20 overnight/opportunity, and 60/40. Energy cost shifts by up to 30% between them.
4. Residual-value sensitivity. Run the model with diesel residuals soft by 10%, 20% and 30%. The case for switching gets stronger every increment.
5. Salary sacrifice uplift. Layer it on as a separate line. Don't bury it in the headline.
6. Grant timing. Depot Charging Scheme applications must precede procurement orders. Get the application in before you sign the depot contract.

The short version

Switching 50 diesel Transit Customs to E-Transits saves around £1.6m in cash over five years against £126k net depot capex (post-DCS grant) and broadly equivalent monthly lease rates. Fuel: £4,750 → £1,140 per van per year. Maintenance: £820 → £340. FYA gives you 100% capital allowance on vans and depot kit. BIK at 3% (2026/27) makes salary sacrifice obvious. Residual-value risk on diesel is real and accelerating. The case isn't whether to switch. It's whether to switch in 2026 or be forced into it in 2029 with worse residuals and a longer DNO queue.

Want us to do the maths on your site?

We have done this model for fleets of 12, 50, 180 and 600 vans. Download the full 50-van case study at /case-studies — line items, sensitivity tables, the actual DCS application timeline, and the bit your existing leasing partner forgot to mention. (Especially the bit about residuals.)

Case Study Download

Read this article in the app at energy-partners.co.uk/insights/electric-van-fleet-tco-uk. Energy Partners installs and manages commercial EV charging, solar and battery storage for UK venues — talk to us.