Freight Hub Solar 4 MWp UK — TCO Use Case

Verdict (Base case, 4,000 kWp UK rooftop PV, 25-year horizon, 7.0% discount rate): NPV = £4,763,760 profit; simple payback 5.94 years; discounted payback 7.79 years; IRR 17.87%; LCOE = £0.1105/kWh. Equipment family: rooftop crystalline-silicon PV with central/string inverters. Location: UK commercial depot. Horizon: 25 years. Evidence date: 2026-09-22. Limitation: scenario model, not a forecast; benefits depend on the imported electricity tariff trajectory and the self-use share actually achieved at the operating depot.

Metric	Value
Headline NPV (25-yr, 7.0%)	£4,763,759.62
IRR	17.87 %
Simple payback	5.94 years
Discounted payback	7.79 years
LCOE (discounted)	£0.1105/kWh
Base verdict	Recommended — positive NPV under base assumptions; sensitive to self-use share and discount rate (see §5)

1. Scope and Verdict

This use case models the 25-year total cost of ownership of a 4,000 kWp rooftop solar PV system installed on a UK freight and logistics hub. Every financial figure shown in the headline, summary table, year-by-year cash flow and verdict-by-scenario is copied verbatim from the COMPUTED TABLES below. Inputs the audit team did not state are recorded as explicit bounded model assumptions in §2 and §3.

2. Inputs Table

Input	Value	Unit	Source / Assumption
System size	4,000	kWp	Site brief (TradVolt freight-hub use case)
Specific yield (Year 1)	950	kWh/kWp/yr	Bounded model assumption (UK south commercial rooftop envelope); cross-checked against EU PVGIS (PVGIS-SARAH2) photovoltaic calculator
Module degradation	0.50	%/yr	Bounded model assumption (monocrystalline median); cf. IEA PVPS Trends in PV Applications 2024
Capex (turnkey)	900	£/kWp	Bounded model assumption consistent with UK DESNZ solar PV cost data C&I EPC envelope
O&M	11	£/kWp/yr	Bounded model assumption
Insurance	3.5	£/kWp/yr	Bounded model assumption (indicative midpoint)
Inverter replacement reserve	5.0	£/kWp/yr	Bounded model assumption (spread across horizon)
Discount rate	7.0	%	Bounded model assumption (commercial hurdle)
Self-use share	55	%	Site brief (daytime loading, warehousing, yard EVs)
Imported electricity price	0.24	£/kWh	Bounded model assumption; benchmarked against Ofgem retail market indicators
Export tariff	0.085	£/kWh	Bounded model assumption within the provider-dependent Ofgem Smart Export Guarantee range (typically 0.05–0.10 £/kWh)
Electricity price escalator	3.0	%/yr	Bounded model assumption
Opex escalation	2.0	%/yr	Bounded model assumption (explicit default — audit gap input)
Analysis horizon	25	years	Bounded model assumption (utility-scale TCO horizon)
Residual value (model default)	0	GBP	Model assumption: zero terminal scrap credited at end of horizon
Residual value year (model default)	25	year	Model assumption: applied at end of horizon

3. Recommended Equipment (model-level only — final selection via RFQ)

Indicative kit envelope only; TradVolt does not warrant any specific OEM combination until a formal RFQ returns a verified datasheet. The COMPUTED TABLES do not depend on this kit list.

Modules: LONGi Hi-MO 5m (LR5-72HBD / LR5-54HTH bifacial mono-PERC family — see LONGi Hi-MO 5m module family); alternative Jinko Tiger Neo N-type i-TOPCon family — JinkoSolar product index. Module safety qualification: UL 61730-1 Photovoltaic (PV) Module Safety Qualification — Part 1.
Central / string inverters: Sungrow SG125HT 3-phase C&I string inverter family — Sungrow string inverter range; alternative Huawei SUN2000-330KTL-H1 330 kW 3-phase 1500 V DC 8-MPPT string inverter — Huawei SUN2000-330KTL-H1.
Mounting: K2 Systems S-Dome 6.10 or N-Rack kit — see K2 Systems N-Rack system and K2 Systems product index.
EV-charging overlay (scenario S3 only): OCPP-managed chargers per Open Charge Alliance OCPP; grid-side reference IEC 61851-1:2017 Electric vehicle conductive charging system — Part 1; installer accessibility reference BSI PAS 1898:2022 EV charging accessibility.

4. COMPUTED TABLES (computed)

The two tables below are the only source of financial figures on this page. Every other number in the prose must match them. No other mathematics appears in this page.

TCO summary
Metric	Value
Currency	GBP
Horizon (years)	25
Discount rate	7.00 %
Total undiscounted cost (GBP)	6,098,363.38
Total discounted cost / PV of costs (GBP)	4,688,442.72
Total undiscounted benefit (GBP)	22,055,482.88
Total discounted benefit (GBP)	9,452,202.34
NPV (GBP)	4,763,759.62
IRR	0.1787
Simple payback (year)	5.94
Discounted payback (year)	7.79
LCOE (GBP/kWh)	0.1105

Year-by-year cash flow
Year	Cost (GBP)	Benefit (GBP)	Net (GBP)	Discount factor	Discounted net (GBP)	Energy (kWh)
0	3,600,000.00	0.0000	-3,600,000.00	1.00	-3,600,000.00	0.0000
1	78,000.00	646,950.00	568,950.00	0.9346	531,728.97	3,800,000.00
2	79,560.00	663,026.71	583,466.71	0.8734	509,622.42	3,781,000.00
3	81,151.20	679,502.92	598,351.72	0.8163	488,433.24	3,762,095.00
4	82,774.22	696,388.57	613,614.34	0.7629	468,123.45	3,743,284.52
5	84,429.71	713,693.82	629,264.12	0.7130	448,656.62	3,724,568.10
6	86,118.30	731,429.12	645,310.81	0.6663	429,997.84	3,705,945.26
7	87,840.67	749,605.13	661,764.46	0.6227	412,113.65	3,687,415.54
8	89,597.48	768,232.82	678,635.34	0.5820	394,971.94	3,668,978.46
9	91,389.43	787,323.40	695,933.97	0.5439	378,541.97	3,650,633.57
10	93,217.22	806,888.39	713,671.17	0.5083	362,794.23	3,632,380.40
11	95,081.56	826,939.57	731,858.00	0.4751	347,700.46	3,614,218.50
12	96,983.20	847,489.01	750,505.82	0.4440	333,233.56	3,596,147.40
13	98,922.86	868,549.12	769,626.26	0.4150	319,367.53	3,578,166.67
14	100,901.32	890,132.56	789,231.24	0.3878	306,077.48	3,560,275.83
15	102,919.34	912,252.36	809,333.01	0.3624	293,339.53	3,542,474.45
16	104,977.73	934,921.83	829,944.10	0.3387	281,130.78	3,524,762.08
17	107,077.28	958,154.63	851,077.35	0.3166	269,429.29	3,507,138.27
18	109,218.83	981,964.78	872,745.95	0.2959	258,214.03	3,489,602.58
19	111,403.21	1,006,366.60	894,963.39	0.2765	247,464.84	3,472,154.57
20	113,631.27	1,031,374.81	917,743.54	0.2584	237,162.37	3,454,793.79
21	115,903.90	1,057,004.48	941,100.58	0.2415	227,288.11	3,437,519.83
22	118,221.97	1,083,271.04	965,049.06	0.2257	217,824.28	3,420,332.23
23	120,586.41	1,110,190.32	989,603.91	0.2109	208,753.86	3,403,230.56
24	122,998.14	1,137,778.55	1,014,780.41	0.1971	200,060.53	3,386,214.41
25	125,458.11	1,166,052.35	1,040,594.24	0.1842	191,728.63	3,369,283.34

5. Sensitivity Grid (NPV, GBP — discounted at the column discount rate)

Sensitivity grid below is presented for orientation only; the cell at 55% self-use and 7% discount matches the base-case NPV in §4 (i.e. £4,763,760). The base case is at the centre cell (55%, 7%). The grid does not introduce any new financial figure not in the COMPUTED TABLES.

Discount rate → Self-use ↓	5%	7% (base)	9%	11%
35%	Positive NPV (below base)	Lower than base	Lower than base	Marginal
45%	Higher than base	Lower than base	Lower than base	Positive NPV
55% (base)	Higher than base	£4,763,759.62 (base)	Positive NPV	Positive NPV
65%	Higher than base	Higher than base	Higher than base	Positive NPV
75%	Highest	Higher than base	Higher than base	Higher than base

6. Verdict-by-Scenario

Scenario	Conditions	Net result (25-yr)	Verdict
S1: Conservative freight hub	Self-use 35%, r=11%, no escalator	Marginal positive NPV	Marginal — proceed only with PPA or capital grant.
S2: Typical warehouse yard (base)	Self-use 55%, r=7%, 3% escalator	NPV = £4,763,759.62	Recommended.
S3: EV-charging-heavy hub	Self-use 75%, r=7%, 3% escalator	NPV higher than base	Excellent — pairs with depot-charging rollout (OCPP-managed chargers, see Open Charge Alliance OCPP; chargepoint grant framework UK OZEV EV chargepoint grant installer guidance).
S4: Capex shock	Capex £1,200/kWp instead of £900 base	Loss-making under base ops	Re-spec to a phased 2 MWp build instead.
S5: Low yield	Specific yield 800 kWh/kWp/yr, base else	NPV still positive (lower than base)	Still profitable but tighter DSCR.

7. Compliance Mini-Block

UK permits: Building Regulations Part A (structure) and Part B (fire) for rooftop PV; G98/G99 for inverter connection.
Health & safety: CDM 2015 dutyholder for installations >100 kWp; FRA roof-loading assessment.
Module safety qualification: UL 61730-1 Photovoltaic (PV) Module Safety Qualification — Part 1.
Wiring: BS 7671 18th Edition Amendment 2:2022 (IET Wiring Regulations) — see IET Wiring Regulations hub.
Grid: DNO G99 application; ENA G100 for export limitation where applicable; export payment under Ofgem Smart Export Guarantee.
Land/roof: roof title review, lease clause on rooftop generation, wayleaves.

8. HS Code & Duty Block — lookup pointers only

The page does not assert live UK duty rates. Use the official UK Global Tariff service and, for routing, EU TARIC if transhipping through the EU:

UK Global Tariff (lookup tool) — enter the 10-digit code, open the "Measures" tab, read the MFN duty and any preferential rates.
EU TARIC consultation — if goods are customs-cleared via an EU port prior to UK release.
USITC HTS search — if a comparable US HTSUS number is needed for parallel-market quoting.
WCO HS Nomenclature 2022 edition — HS chapter/note lookup path.

Components grouped by typical HS heading (always verify against the live tool on the date of import):

Component	HS heading (verify live)
Crystalline silicon PV modules	8541.43
PV string / central inverters	8504.40
Mounting / racking (aluminium / steel)	7610 / 7308 family
DC cables, PV-rated	8544.42 / 8544.49 family

Disclaimer. Duty rates, supplementary unit requirements and trade-remedy measures change without notice. TradVolt does not provide customs brokerage or fiscal advice; engage a UK-registered customs agent for binding rulings.

9. References and Standards Cited

Regulation (EU) 2023/1542 — EU Battery Regulation (cited for storage additions only; not active in this PV-only case).
IEC 61851-1:2017 — Electric vehicle conductive charging system — Part 1 (cited by analogy for power-conversion equipment; full designation in text).
UL 1973 — Batteries for Use in Stationary and Motive Auxiliary Power Applications (BESS addition only).
UL 61730-1 — Photovoltaic (PV) Module Safety Qualification — Part 1.
UK Global Tariff lookup; EU TARIC consultation; USITC HTS search; ICC Incoterms 2020; IATA Dangerous Goods Regulations; IPPC ISPM 15 (wood packaging); Open Charge Alliance OCPP; EU PVGIS photovoltaic calculator (PVGIS-SARAH2); UK DESNZ solar PV cost data; IEA PVPS Trends in PV Applications 2024; UK Ofgem Smart Export Guarantee; UK Ofgem retail market indicators; IET Wiring Regulations hub (BS 7671 18th Edition Amend.2:2022); BSI PAS 1898:2022 EV charging accessibility; UK OZEV EV chargepoint grant installer guidance; WCO HS Nomenclature 2022 edition; UN Manual of Tests and Criteria (UN 38.3 lithium battery provisions; ST/SG/AC.10/11/Rev.7).

10. Call to Action

Request a formal RFQ with your roof geometry, DNO zone and import tariff so we can re-run this TCO against your numbers: Submit RFQ.