Fleet Savings UK - Methodology (Business Edition)

Fleet electrification is a board-level decision. Our Fleet Savings UK methodology provides a transparent, UK-specific comparison of diesel versus electric fleets so you can quantify savings, risk and ROI with confidence.

What do we measure?

• Operating costs. Fuel or electricity, maintenance and tyres, road tax (VED), employer National Insurance (NIC)on benefits, and London road-user charges where relevant (ULEZ, Congestion Charge). Multi-year costs are projected and converted to present value so you see the true lifetime cost.Facts: From 1 April 2025, EVs pay VED; standard rate £195 from year two, with an Expensive Car Supplementfor list price > £40,000 (years 2-6). EV drivers currently benefit from the Congestion Charge Cleaner Vehicle Discount until 25 December 2025.Sources: GOV.UK - VED for EVs, VED rate tables, TfL - Cleaner Vehicle Discount
• Capital & residuals. Vehicle purchase (net of incentives), charging infrastructure (home, depot or public), and residual values at resale. Infrastructure can be allocated per vehicle or per site to match your deployment plan.
• Tax & compliance. Benefit-in-Kind (BiK) schedules for zero-emission company cars and the associated employer NIC are included, reflecting confirmed rates out to 2029/30.Sources: HMRC/HMT - BiK 2025-2028, BiK 2028-2030
• Energy & reimbursement. Consumption (kWh/mile and mpg) by duty cycle and charging mix, charging losses, and reimbursement benchmarks, including HMRC's Advisory Electricity Rate (AER) 7p/mile (effective 1 June 2025).Sources: HMRC - Advisory fuel & electricity rates, RAC - Fuel Watch
• Urban access charges. For London, we include ULEZ (£12.50/day) and Congestion Charge (£15/day) where applicable, plus the Cleaner Vehicle Discount end-date. Note: TfL has consulted on raising the Congestion Charge to £18 from January 2026 and introducing new EV discounts (subject to final decision).Sources: TfL - ULEZ, TfL - Congestion Charge, TfL consultation

How we convert inputs into fleet savings

1. Scope & baseline - Fleet size and mix, annual miles, urban/inter-urban split, and charging locations (home, depot, public AC/DC).
2. Energy economics - kWh/mile (EV) and mpg (diesel) by duty cycle; tariffs and pump prices; charging losses; optional smart-tariff scenarios for home/depot.
3. Fiscal & policy - Apply VED by registration and list price, zero-emission BiK schedules and employer NIC, and London charges (ULEZ, Congestion Charge).
4. Capital & infrastructure - Vehicle capex, charger capex (per vehicle/site), residuals and the Expensive Car Supplement for cars > £40k.
5. Time value & sensitivity - Discount multi-year cashflows; run sensitivities for energy prices, charging mix, utilisation, residuals and policy changes (e.g., end of the Cleaner Vehicle Discount; potential 2026 congestion-charge change).

Outputs you receive

• Per-vehicle & fleet-level TCO (diesel vs EV, present-value basis)
• Fleet savings (annual and lifetime deltas vs baseline)
• Payback & ROI with scenario bands (base / optimistic / conservative)
• Top levers to maximise savings (e.g., shift to home/depot charging; BiK-optimised company-car policy)

Trusted sources 

• HMRC - Advisory Electricity Rate (AER): 7p/mile from 1 June 2025https://www.gov.uk/guidance/advisory-fuel-rates
• GOV.UK/DVLA - VED for EVs from 1 April 2025; standard rate £195; Expensive Car Supplement for cars > £40,000https://www.gov.uk/guidance/vehicle-tax-for-electric-and-low-emissions-vehicles - https://www.gov.uk/vehicle-tax-rate-tables
• HM Treasury/HMRC - BiK trajectory (zero-emission): 2025/26 → 2027/28 (+1ppt yearly), 2028/29 → 2029/30 (+2ppt yearly)https://www.gov.uk/government/publications/income-tax-increasing-the-appropriate-percentage-for-company-cars/taxation-of-company-cars-the-appropriate-percentage-for-tax-years-2025-to-2026-2026-to-2027-and-2027-to-2028 - https://www.gov.uk/government/publications/income-tax-company-car-tax-rates-2028-to-2030
• HMRC - Employer NIC on benefits (Class 1A/1B): 15% from 6 April 2025https://www.gov.uk/national-insurance-rates-letters - https://www.gov.uk/government/publications/cwg5-class-1a-national-insurance-contributions-on-benefits-in-kind/2025-class-1a-national-insurance-contributions-on-benefits-in-kind-termination-payments-and-sporting-testimonial-payments
• TfL - ULEZ £12.50/day; Congestion Charge £15/day; Cleaner Vehicle Discount ends 25 Dec 2025; 2026 charge proposal to £18https://tfl.gov.uk/modes/driving/ultra-low-emission-zone - https://tfl.gov.uk/modes/driving/congestion-charge - https://tfl.gov.uk/modes/driving/discounts-and-exemptions - https://haveyoursay.tfl.gov.uk/congestion-charge-proposals
• RAC - Fuel Watch (diesel/petrol benchmarks)https://www.rac.co.uk/drive/advice/fuel-watch/

What does this means for fleet leaders?

• Savings are real - but policy-sensitive. EVs retain a structural advantage under current BiK and AER rules; VED and London charges add nuance by list price, geography and duty cycle. (Facts from sources above.)
• Charging mix is the #1 lever. Every shift from rapid public DC to home/depot charging reduces £/mile and typically shortens payback. (Our view, based on modelling experience.)
• Company-car policy can unlock demand. Salary-sacrifice/BEV policies remain attractive due to low BiK through 2027/28; model your NIC and P11D exposure carefully. (Facts + our view.)

Call to action

• Run your Fleet Savings scenario (≈2 minutes). We'll email a tailored PDF with assumptions and sensitivities: Fleet-savings.evdatacompare.com
• Prefer a working session? Book a 20-minute ROI review with our team, contact us at contact (at) evdc.co
  

Important: This methodology provides indicative, policy-aligned estimates and does not replace tailored financial advice. Always validate assumptions (prices, tax rates, incentives) before committing spend.