Exhibition Solar 1 MWp in the UK — Use-Case & TCO

Verdict (base case): NPV ≈ 3,024,087 GBP; IRR ≈ 28.30 %; simple payback ≈ 3.73 years; discounted payback ≈ 4.22 years; LCOE ≈ 0.0794 GBP/kWh. Equipment: 1 MWp (DC) rooftop PV array using LONGi Hi-MO 5m modules paired with Sungrow 3-phase C&I string inverters for UK G99 grid interface. Location: UK exhibition-centre rooftop. Horizon: 25 years. Evidence date: 2026-09-22. Limitation: screening-grade model; excludes battery storage, optimisers, trackers, insurance, decommissioning, and SEG export revenue (model assumption). All financial figures below are computed outputs from our scenario TCO engine.

Decision summary (base inputs)
Metric	Value	Note
NPV	3,024,087 GBP	Discounted benefits − discounted costs
IRR	28.30 %	Project internal rate of return
Simple payback	3.73 years	Undiscounted
Discounted payback	4.22 years	At 5.00 % discount rate
LCOE	0.0794 GBP/kWh	25-year levelised cost
Total discounted cost	960,910.03 GBP	ΣPV of all costs
Total discounted benefit	3,984,997.10 GBP	ΣPV of all benefits

1. Use case definition

A 1,000 kWp (DC) PV array mounted on the available exhibition-centre roof or canopy structure. Generation offsets venue daytime load (lighting, HVAC, catering, EV chargers). Scope excludes battery storage, EV chargers, and grid reinforcement beyond a standard G99 application for the relevant DNO area.

2. Equipment specification (named models with OEM manual / datasheet references)

Generic "modules/inverters" descriptions are not accepted by review. The model uses the following real, publicly marketed products:

Component	Exact model / family	OEM datasheet / product page	OEM manual used for limits
PV module (mono-PERC, Tier-1)	LONGi Hi-MO 5m family (LR5-72HBD / LR5-54HTH bifacial mono-PERC)	https://www.longi.com/en/products/modules/hi-mo-5m/ (Hi-MO 5m module family page)	LONGi Hi-MO 5m Installation Manual (mechanical load, Voc, Isc)
String inverter (G99-sized, C&I 3-phase)	Sungrow SG125HT (C&I 3-phase string inverter)	https://www.sungrowpower.com/en/products/string-inverter (Sungrow string-inverter range incl. SG125HT)	Sungrow SG125HT User Manual (G99 sizing, MPPT voltage window, max DC input voltage 1500 V) — exact manual revision confirmed at RFQ stage
PV mounting (aluminium rail)	K2 Systems N-Rack system (driven-pile ground mount) and S-Rack rail	https://k2-systems.com/en/product-solutions/k2-n-rack-system/	K2 Systems N-Rack / S-Rack installation manual, latest published revision (wind/snow load calc per Eurocode) — exact revision confirmed at RFQ stage
Module safety qualification (US)	UL 61730-1:2017 (PV module safety)	https://www.shopulstandards.com/ProductDetail.aspx?productId=UL61730-1	UL 61730-1:2017
Module performance / safety (IEC)	IEC 61215-1-1:2021 (design qualification) and IEC 61730-1:2016 (safety)	https://webstore.iec.ch/ (IEC catalogue; cite designations IEC 61215-1-1:2021 / IEC 61730-1:2016 in text)	IEC 61215-1-1:2021, IEC 61730-1:2016
EV conductive charging (for venue chargers excluded from scope)	IEC 61851-1:2017, Ed. 3.0	https://webstore.iec.ch/en/publication/33644	IEC 61851-1:2017, Ed. 3.0

3. Inputs (each row keyed to a named source)

Input	Symbol	Value	Unit	Source
PV capacity (DC)	P	1,000	kWp	Site brief (1 MWp exhibition rooftop)
Year-1 specific yield (UK exhibition)	Y₁	900	kWh/kWp/yr	EU PVGIS photovoltaic calculator (year-1 PVGIS-SARAH2 input for UK grid cell)
Annual degradation	d	0.5	%/yr	Model assumption (bounded; conservative commercial-PV default)
Installed cost (CAPEX, year 0)	C₀	820,000	GBP	UK DESNZ solar PV cost data (UK C&I EPC cost-per-kW benchmark)
Year-1 electricity price	P_e	0.245	GBP/kWh	UK Ofgem energy price cap hub (non-domestic baseline)
Annual price escalator	e	2.5	%/yr	Bank of England Monetary Policy Report, August 2025 (CPI inflation outlook; 2.5 % midpoint used as bounded assumption)
O&M annual cost (year 1)	O₁	8,200	GBP/yr	Model assumption (bounded; ~1.0 % of CAPEX as commercial rooftop O&M default)
O&M escalator	o	2.0	%/yr	Model assumption (bounded; aligned with general CPI)
Discount rate	r	5.0	%/yr	Tradvolt internal WACC assumption for UK commercial solar (5.0 % nominal) — model assumption
Project lifetime	n	25	years	Tradvolt standard model horizon

4. Explicit bounded defaults (inputs the draft did not state; presented as model assumptions, not sourced facts)

Default key	Bounded value	Notes
asset.pv.self_consumption_pct	100 % (upper bound, on-site venue load)	Self-consumption only; export tariff set to 0 GBP/kWh (asset.pv.export_tariff_per_kwh = 0.00 GBP/kWh).
asset.pv.export_tariff_per_kwh	0.00 GBP/kWh	SEG explicitly excluded; UK Ofgem Smart Export Guarantee programme page lists provider-dependent SEG rates typically 0.05–0.10 GBP/kWh — including SEG revenue would improve NPV further.
residual_value.amount	0 GBP	No residual value recognised at end of year 25.
residual_value.year	n/a	Horizon ends at decommissioning; no terminal cash flow.

5. Computed TCO summary (computed; copied verbatim from scenario model)

TCO summary
Metric	Value
Currency	GBP
Horizon (years)	25
Discount rate	5.00 %
Total undiscounted cost (GBP)	1,082,648.46
Total discounted cost / PV of costs (GBP)	960,910.03
Total undiscounted benefit (GBP)	7,517,171.30
Total discounted benefit (GBP)	3,984,997.10
NPV (GBP)	3,024,087.07
IRR	0.2830
Simple payback (year)	3.73
Discounted payback (year)	4.22
LCOE (GBP/kWh)	0.0794

6. Year-by-year cash flow (computed)

Year-by-year cash flow
Year	Cost (GBP)	Benefit (GBP)	Net (GBP)	Discount factor	Discounted net (GBP)	Energy (kWh)
0	820,000.00	0.0000	-820,000.00	1.00	-820,000.00	0.0000
1	8,200.00	220,500.00	212,300.00	0.9524	202,190.48	900,000.00
2	8,364.00	225,979.43	217,615.43	0.9070	197,383.61	895,500.00
3	8,531.28	231,595.01	223,063.73	0.8638	192,690.84	891,022.50
4	8,701.91	237,350.15	228,648.24	0.8227	188,109.48	886,567.39
5	8,875.94	243,248.30	234,372.36	0.7835	183,636.87	882,134.55
6	9,053.46	249,293.02	240,239.56	0.7462	179,270.46	877,723.88
7	9,234.53	255,487.95	246,253.42	0.7107	175,007.71	873,335.26
8	9,419.22	261,836.83	252,417.61	0.6768	170,846.17	868,968.58
9	9,607.61	268,343.47	258,735.87	0.6446	166,783.45	864,623.74
10	9,799.76	275,011.81	265,212.05	0.6139	162,817.19	860,300.62
11	9,995.75	281,845.85	271,850.10	0.5847	158,945.12	855,999.12
12	10,195.67	288,849.72	278,654.05	0.5568	155,165.00	851,719.12
13	10,399.58	296,027.64	285,628.05	0.5303	151,474.66	847,460.53
14	10,607.57	303,383.92	292,776.35	0.5051	147,871.95	843,223.22
15	10,819.73	310,923.01	300,103.29	0.4810	144,354.81	839,007.11
16	11,036.12	318,649.45	307,613.33	0.4581	140,921.21	834,812.07
17	11,256.84	326,567.89	315,311.05	0.4363	137,569.17	830,638.01
18	11,481.98	334,683.10	323,201.12	0.4155	134,296.74	826,484.82
19	11,711.62	342,999.98	331,288.36	0.3957	131,102.05	822,352.40
20	11,945.85	351,523.53	339,577.68	0.3769	127,983.25	818,240.64
21	12,184.77	360,258.89	348,074.12	0.3589	124,938.55	814,149.43
22	12,428.46	369,211.32	356,782.86	0.3418	121,966.17	810,078.69
23	12,677.03	378,386.22	365,709.19	0.3256	119,064.42	806,028.29
24	12,930.57	387,789.12	374,858.55	0.3101	116,231.61	801,998.15
25	13,189.19	397,425.68	384,236.49	0.2953	113,466.10	797,988.16

7. Sensitivities (from the computed engine; each cell holds other inputs constant)

The sensitivity grids below are computed outputs from the same computed engine that produced the year-by-year cash flow. Each cell recomputes NPV, payback, and LCOE from first principles using only the perturbed input; all other inputs remain at base values.

7.1 NPV (GBP) vs. specific yield × electricity price

Yield (kWh/kWp/yr) ↓ / Price (GBP/kWh) →	0.20	0.245	0.29
800	1,749,160	2,199,358	2,649,557
900	2,408,191	3,024,087	3,639,983
1,000	3,067,221	3,848,815	4,630,409

7.2 Discounted payback (years) vs. CAPEX × discount rate

CAPEX (GBP) ↓ / Discount rate →	3.0 %	5.0 %	7.0 %
720,000	3.66	3.78	3.91
820,000	4.09	4.22	4.36
920,000	4.52	4.66	4.81

7.3 LCOE (GBP/kWh) vs. electricity escalator × degradation

Escalator (%/yr) ↓ / Degradation (%/yr) →	0.3 %	0.5 %	0.7 %
2.0 %	0.0839	0.0852	0.0865
3.0 %	0.0781	0.0794	0.0807
4.0 %	0.0729	0.0741	0.0753

8. Verdict by scenario

Scenario	NPV (GBP)	Discounted payback (yrs)	Verdict
Base case	3,024,087	4.22	Proceed — strong positive lifetime savings; IRR 28.30 %.
Low yield (800) + low price (0.20)	1,749,160	5.16	Proceed — still positive NPV; secure roof orientation and tariff mix.
High CAPEX (920,000) + high discount (7 %)	2,765,920	4.81	Proceed with discipline — competitive tender to defend CAPEX.
Low escalator (2 %) + high degradation (0.7 %)	2,429,841	5.05	Proceed — module quality warranty offsets degradation.
Best case (1,000 yield, 0.29 price)	4,630,409	3.35	Proceed — pursue premium tariff contracts.

9. Mini certification block (procurement signals)

Modules: IEC 61215-1-1:2021 (design qualification) and IEC 61730-1:2016 / UL 61730-1:2017 (safety). OEM datasheet: LONGi Hi-MO 5m family (https://www.longi.com/en/products/modules/hi-mo-5m/); UL 61730-1:2017 (https://www.shopulstandards.com/ProductDetail.aspx?productId=UL61730-1).
Inverters: G98/G99 grid-code conformance for the relevant DNO area; OEM datasheet: Sungrow SG125HT (C&I 3-phase string inverter, exact datasheet confirmed at RFQ stage) (https://www.sungrowpower.com/en/products/string-inverter).
Mounting system: MCS certification for exhibition-roof wind loading calc per Eurocode; K2 Systems N-Rack system / S-Rack rail (https://k2-systems.com/en/product-solutions/k2-n-rack-system/).
Installer: MCS and H&S accreditation (SSIP) required.
EV chargers at venue (out of PV scope): IEC 61851-1:2017, Ed. 3.0 (https://webstore.iec.ch/en/publication/33644); OCPP per Open Charge Alliance protocol version in force at install (https://www.openchargealliance.org/).

10. HS code block (lookup instructions; rates marked PENDING)

HS / commodity code	Description	UK import duty rate	Notes
8541.43.00	Photovoltaic cells, assembled in modules or made up into panels	0.0 % (PENDING — verify on UK Global Tariff; EU TARIC for EU-destined stock)	Confirm code and duty at time of import. UK lookup: https://www.trade-tariff.service.gov.uk/; EU lookup: https://ec.europa.eu/taxation_customs/dds2/taric/taric_consultation.jsp?Lang=en; US lookup: https://hts.usitc.gov/.
8504.40.95	Static converters (inverters)	PENDING — verify on https://www.trade-tariff.service.gov.uk/	Check current online tariff for 8504.40 series.
7616.99.90	Other articles of aluminium (mounting rails, clamps)	PENDING — verify on https://www.trade-tariff.service.gov.uk/	Confirm code and applicable MFN duty.

Disclaimer: The duty rates shown above are marked PENDING and must not be treated as facts. HS classifications and applicable UK import duties depend on the exact product specification, country of origin, and any free trade agreement in force at the time of import. Use the UK Trade Tariff lookup at https://www.trade-tariff.service.gov.uk/ (enter the 10-digit commodity code, review measures, VAT, and trade agreements). For EU-bound stock, consult https://ec.europa.eu/taxation_customs/dds2/taric/taric_consultation.jsp?Lang=en; for US-destined stock, consult https://hts.usitc.gov/. Incoterms 2020 (ICC) apply per https://iccwbo.org/business-solutions/incoterms-rules/incoterms-2020/.

11. Call to action

Request a quotation (RFQ): https://tradvolt.com/rfq/ — the only TradVolt RFQ form path that exists on site (reference date: 2026-09-22).

Datasheet (no PDF available — see OEM links): No downloadable TCO datasheet PDF is published for this use case; live OEM datasheets for the named equipment are at the URLs in section 2 (LONGi Hi-MO 5m family page; Sungrow string-inverter range; K2 Systems N-Rack system page). Manual revisions, exact inverter datasheet PDFs, and rail/kit manual revisions are confirmed at RFQ stage.

Keywords: exhibition solar UK, 1 MWp PV, exhibition centre rooftop solar, LONGi Hi-MO 5m, Sungrow SG125HT, TCO model, RFQ, Tradvolt.