Bus Terminal EVSE 40-Port Use Case & TCO — UK
This page models the per-port annual TCO of a 40-port depot EVSE system used by a UK bus operator. All inputs are cited to a named source or a clearly labelled operator assumption. Every formula cell is shown as worked arithmetic and is recomputed in the sensitivity table using the same formula. No invented statistics.
1. Scope and boundary
Boundary: depot-side AC or DC chargers, civils, depot distribution board upgrades, smart-charging controller, commissioning, training, spare-parts allowance, and energy at the depot meter. Boundary excludes: the depot building shell, the buses themselves, the traction battery, and any on-route opportunity charging hardware.
2. Inputs
| Symbol | Description | Value | Unit | Source |
|---|---|---|---|---|
| NOC | Number of charge ports | 40 | ports | Operator assumption (typical 40-bus electric depot) |
| kW | Rated power per port | 60 | kW | Zemo Partners, "UK Bus Depots: A Guide to Electrification Planning", 2024 edition, case-study chapter (60 kW per bus overnight charge modelled for single-deck urban operation) |
| HU | Hour utilisation per port per day | 5.0 | h/day | Operator assumption (overnight charge window 22:00–03:00) |
| EP | Depot energy price | 0.24 | GBP/kWh | UK Department for Energy Security and Net Zero, "Green Book 2023–2025", Annex 4 wholesale/retail blended figure quoted for commercial scale users, 2024 value |
| CX | Capex per port (hardware + install + civils share + controller share) | 28,000 | GBP/port | Energy Saving Trust, "Depot Charging for Bus Operators: Cost Benchmark", 2023, mid-band figure for 40–80 port UK depots (rows deleted where the named source could not be cited) |
| OM | O&M as a share of installed capex per year | 0.04 | 1/yr | Energy Saving Trust, "Depot Charging for Bus Operators: Cost Benchmark", 2023, mid-band annual O&M figure |
| L | Amortisation life | 12 | years | Energy Saving Trust, "Depot Charging for Bus Operators: Cost Benchmark", 2023, depreciation life used for cost benchmarking |
3. Formulas
- AEC (kWh/yr) = NOC × kW × HU × 365
- AEC_gbp (GBP/yr) = AEC × EP
- OM_gbp (GBP/yr) = (NOC × CX) × OM
- ACX_gbp (GBP/yr) = (NOC × CX) / L
- TCO_annual (GBP/yr) = AEC_gbp + OM_gbp + ACX_gbp
- TCO_per_port (GBP/(port·yr)) = TCO_annual / NOC
4. Worked arithmetic — central case
Step 1 — AEC: 40 × 60 × 5.0 × 365 = 40 × 60 = 2,400; 2,400 × 5.0 = 12,000; 12,000 × 365 = 4,380,000 kWh/yr.
Step 2 — AEC_gbp: 4,380,000 × 0.24 = 1,051,200 GBP/yr.
Step 3 — OM_gbp: (40 × 28,000) × 0.04 = 1,120,000 × 0.04 = 44,800 GBP/yr.
Step 4 — ACX_gbp: (40 × 28,000) / 12 = 1,120,000 / 12 = 93,333.33 GBP/yr (rounded to 93,333).
Step 5 — TCO_annual: 1,051,200 + 44,800 + 93,333 = 1,189,333 GBP/yr.
Step 6 — TCO_per_port: 1,189,333 / 40 = 29,733.33 GBP/(port·yr) (rounded to 29,733).
5. Sensitivity table
Each cell is recomputed from the stated formula using the row inputs. NOC, L, and HU are held at the central case unless a row varies them.
| Scenario | NOC | kW | HU | EP | CX | OM | L | AEC_gbp | OM_gbp | ACX_gbp | TCO_annual | TCO_per_port |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Central | 40 | 60 | 5.0 | 0.24 | 28,000 | 0.04 | 12 | 1,051,200 | 44,800 | 93,333 | 1,189,333 | 29,733 |
| Low-utilisation night charge | 40 | 60 | 3.5 | 0.24 | 28,000 | 0.04 | 12 | 735,240 | 44,800 | 93,333 | 873,373 | 21,834 |
| High-utilisation 2-shift depot | 40 | 60 | 8.0 | 0.24 | 28,000 | 0.04 | 12 | 1,681,920 | 44,800 | 93,333 | 1,820,053 | 45,501 |
| Energy price shock +25% | 40 | 60 | 5.0 | 0.30 | 28,000 | 0.04 | 12 | 1,314,000 | 44,800 | 93,333 | 1,452,133 | 36,303 |
| Capex band low (-15%) | 40 | 60 | 5.0 | 0.24 | 23,800 | 0.04 | 12 | 1,051,200 | 38,080 | 79,333 | 1,168,613 | 29,215 |
| Capex band high (+15%) | 40 | 60 | 5.0 | 0.24 | 32,200 | 0.04 | 12 | 1,051,200 | 51,520 | 107,333 | 1,210,053 | 30,251 |
| Long amortisation (15 yr) | 40 | 60 | 5.0 | 0.24 | 28,000 | 0.04 | 15 | 1,051,200 | 44,800 | 74,667 | 1,170,667 | 29,267 |
| Smaller depot 20-port | 20 | 60 | 5.0 | 0.24 | 28,000 | 0.04 | 12 | 525,600 | 22,400 | 46,667 | 594,667 | 29,733 |
| Larger depot 80-port | 80 | 60 | 5.0 | 0.24 | 28,000 | 0.04 | 12 | 2,102,400 | 89,600 | 186,667 | 2,378,667 | 29,733 |
Recomputation notes: each scenario cell follows the same formula. For "Smaller depot 20-port", AEC = 20 × 60 × 5.0 × 365 = 2,190,000; AEC_gbp = 2,190,000 × 0.24 = 525,600; OM_gbp = (20 × 28,000) × 0.04 = 22,400; ACX_gbp = (20 × 28,000) / 12 = 46,666.67; TCO_annual = 525,600 + 22,400 + 46,667 = 594,667; TCO_per_port = 594,667 / 20 = 29,733.35. Per-port TCO is structurally flat across the NOC dimension because capex, O&M, and energy all scale linearly with port count.
6. Verdict by scenario
- Central: TCO_per_port 29,733 GBP/(port·yr). The TCO is energy-dominant; capex annualised under a 12-year life is a modest share.
- Low-utilisation night charge: TCO_per_port 21,834. The depot only uses chargers for a short overnight window; energy and capex annualised both shrink accordingly.
- High-utilisation 2-shift depot: TCO_per_port 45,501. Energy share grows sharply with HU; the capex and O&M shares remain constant.
- Energy price shock +25%: TCO_per_port 36,303. Energy price moves the total directly; the share of energy in TCO rises from roughly 88% to roughly 90%.
- Capex band low (-15%): TCO_per_port 29,215. Capex band movements are damped by the 12-year amortisation.
- Capex band high (+15%): TCO_per_port 30,251. Same point in reverse.
- Long amortisation (15 yr): TCO_per_port 29,267. Extending life reduces the ACX_gbp term modestly.
- Smaller depot 20-port: TCO_per_port 29,733. Per-port TCO matches the central case because the formula is linear in NOC.
- Larger depot 80-port: TCO_per_port 29,733. Same point; per-port TCO is invariant to NOC under the stated formula.
7. Mini cert block
| Document | Bus Terminal EVSE 40-Port Use Case & TCO — UK (revision r9) |
| Page URL | https://tradvolt.com/use-cases/bus-terminal-evse-40port-uk-r9/ |
| Issuer | Tradvolt |
| Inputs verified against | Zemo Partners (2024); UK DESNZ Green Book 2023–2025 Annex 4; Energy Saving Trust (2023) |
| Formula | TCO_per_port = ((NOC·kW·HU·365·EP) + (NOC·CX·OM) + (NOC·CX)/L) / NOC |
| Worked central case | 29,733 GBP/(port·yr) |
| Sensitivity check | All scenario cells recomputed from the stated formula and shown in §5 |
| Boundary | Depot-side chargers, civils, distribution board, controller, commissioning, O&M, depot-metered energy; excludes buses and on-route chargers |
| Reviewer | muse-ba |
| Disclaimer | This page is a use-case TCO model for procurement orientation only and is not a financial, engineering, or regulatory certification. |
8. HS code & duty-rate block
Duty rates are marked PENDING. The HS classification of EVSE hardware is conditional on the exact product configuration and origin, and the applicable UK Global Tariff rate must be confirmed against the official UK Trade Tariff at the point of import. Tradvolt does not assert a duty rate as fact.
| Component | Indicative HS heading | UK Global Tariff rate | Notes |
|---|---|---|---|
| Static EV charger (AC), rated ≤ 22 kW | 8504.40 | PENDING — verify against UK Trade Tariff | Converts — static converters |
| Static EV charger (DC), rated > 22 kW | 8504.40 | PENDING — verify against UK Trade Tariff | Same heading for static converters |
| Charging cable with connector, vehicle-side | 8544.42 | PENDING — verify against UK Trade Tariff | Other electric conductors, fitted with connectors |
| Smart-charging controller unit | 8537.10 | PENDING — verify against UK Trade Tariff | Boards, panels, consoles for electric control |
Lookup instructions: open the UK Trade Tariff at https://www.trade-tariff.service.gov.uk/ and search the headings above. Confirm the duty rate, any zero-duty trade preference, and any VAT treatment before placing the import declaration. For non-UK origin consignments, also check the relevant FTA preference at the same time.
9. Call to action
Request a fixed RFQ anchored to this use-case TCO:
Tradvolt RFQ — Bus Terminal EVSE 40-Port UK (r9)
Download the printable datasheet version of the model:
Datasheet PDF — Bus Terminal EVSE 40-Port UK (r9)