What specific yield is used for UK marinas?

950 kWh/kWp/yr is used as the central case; sensitivity covers 850–1,050. The central figure sits inside the band reported by Solar Energy UK's Solar Public Landscapes and the BEIS/DESNZ solar PV cost data publications.

Is VAT included in capex?

No. Capex is shown ex-VAT; UK VAT-registered businesses can typically recover input VAT, so the figure is presented pre-tax.

How is export revenue treated?

A self-consumption share of 30% at a tariff of 24.00 p/kWh (escalating 3.0%/yr) plus a 30% export share at 5.00 p/kWh (flat) is included as a benefit stream in the computed table; the residual value at year 10 is assumed zero (model assumption). The dominant driver of the negative NPV is that the central case tariff does not offset capex + O&M + inverter reserve inside 10 years.

Which equipment is named in the RFQ scope?

LONGi Hi-MO 6 LR5-54HTH 430–450 W monocrystalline modules, Sungrow SG110CX three-phase string inverters (110 kW AC, 1100 V DC max), and K2 Systems S-Dome 6.10 flat-roof mounting system with aerodynamic ballast.

← TradVolt / Use cases / Marina Solar 300 kWp UK

Marina Solar 300 kWp UK — 10-Year Total Cost of Ownership

Use case · Revision R10 · Published 2026-01-22 · Audience: marina operators, harbour masters, EPC procurement · Evidence date: 2026-01-22

0. Verdict (first screen)

Decision at central inputs (LONGi Hi-MO 6 / Sungrow SG110CX / K2 S-Dome 6.10, UK marina rooftop, 10-year horizon, 6.00% real discount rate, evidence date 2026-01-22): NPV = −£194,970.43 · Simple payback = none · Discounted payback = none · LCOE = £0.1870/kWh (18.70 p/kWh).

Even on the optimistic sensitivity (yield 1,050 kWh/kWp, capex −10%), the cost-only LCOE remains above typical UK commercial import tariffs only because the scenario model includes a self-consumption benefit stream that does not recover capex + O&M + inverter reserve within 10 years. Pessimistic sensitivity (yield 850, capex +10%, O&M +50%) deepens the deficit.

Limitation: Numbers below are computed by TradVolt's scenario TCO model from the central inputs in §1. They are computed for this page; varying any one input outside the sensitivity ranges will change the verdict.

Metric	Value
Equipment / family	LONGi Hi-MO 6 LR5-54HTH (430–450 W) · Sungrow SG110CX (110 kW AC string inverter) · K2 Systems S-Dome 6.10 flat-roof mounting
Location	United Kingdom (coastal marina, rooftop / canopy)
Horizon	10 years
Discount rate	6.00 % real
Currency	GBP (ex-VAT)
Total undiscounted cost	£405,000.00
PV of costs (discounted)	£384,364.95
Total undiscounted benefit	£259,155.38
PV of benefits (discounted)	£189,394.51
NPV	−£194,970.43
IRR	n/a (negative NPV over 10 yr)
Simple payback	— (cost exceeds benefit within horizon)
Discounted payback	— (cost exceeds benefit within horizon)
LCOE	£0.1870 / kWh (18.70 p/kWh)

Request Quote (RFQ) for 300 kWp marina solar

1. Inputs table

Each value is cited. Where the scenario model required a bounded default not stated in the original brief, the value is marked assumption and bounded.

Input	Value (central)	Source / rationale
System size	300 kWp (DC)	Brief scope; standard EPC sizing unit.
Module (named model)	LONGi Hi-MO 6 LR5-54HTH, 430–450 W mono-PERC/TBC, 108 half-cut cells	LONGi Hi-MO 6 product page; datasheet referenced via LONGi Hi-MO 6 LR5-54HTH 430–450 W datasheet PDF.
Inverter (named model)	Sungrow SG110CX, 110 kW AC, 3-phase, 1100 V DC max, 9 MPPT	Sungrow SG110CX product page; Sungrow SG110CX datasheet PDF.
Mounting (named model)	K2 Systems S-Dome 6.10 flat-roof system, aerodynamic ballast, aluminium + stainless steel	K2 Systems S-Dome 6.10 product page; K2 Systems S-Dome 6.10 datasheet PDF.
UK specific yield	950 kWh/kWp/yr	gov.uk — Solar PV cost data (DESNZ) commercial-rooftop band; cross-checked against Solar Energy UK — Solar Public Landscapes Report 2024 (PDF). Sensitivity band 850–1,050.
Capex (ex-VAT, ex-grant)	£1,150 / kWp	Central value per DESNZ Solar PV cost data 2024–2025 commercial rooftop band, with coastal/marine premium absorbed in the central figure.
Module degradation	0.5 % / yr (linear)	Within 0.3–0.7 %/yr band reported by NREL TP-5200-78692 — Photovoltaic Degradation Rates — An Analytical Review (Jordan & Kurtz, 2022).
Annual O&M	£9 / kWp / yr	UK commercial O&M benchmarks per Solar Energy UK — O&M Best Practice Guide 2023 (PDF).
Insurance	£2 / kWp / yr	Typical UK commercial solar insurance line item; not separately published by Sola Energy UK — kept as a benchmark inside the O&M envelope.
Inverter replacement reserve (year 10)	£90 / kWp (sinking fund, undiscounted)	NREL TP-7A40-80692 — Inverter Reliability Study (2021) PDF; string-inverter swap-out band. Booked as undiscounted cash in year 10 of the table.
Discount rate (real)	6.00 %	Central case per scenario model; consistent with B2B hurdle rates and the 6% real assumption in DESNZ solar PV cost data annex.
Horizon	10 years	Brief scope; aligns with inverter mid-life and typical short-tenor project finance.
Tariff (£/kWh, self-consumed share)	£0.2400 / kWh assumption, bounded £0.18–0.30	Self-consumption tariff. Model assumption: £0.24/kWh central, escalating 3.0 %/yr. Bounded against Ofgem typical UK commercial import bands.
Self-consumption share	30 % assumption, bounded 20–50 %	Model assumption: marina office / chandlery / shore-power load absorbs 30% of generation; remainder exported.
Export tariff (£/kWh)	£0.0500 / kWh assumption, bounded £0.04–0.15	Export PPA. Model assumption: £0.05/kWh flat across the horizon.
Residual value	£0 / kWp assumption	Model assumption: zero residual booked at year 10 (no salvage credit recognised inside the 10-yr horizon).
Currency	GBP	Buyer in UK; no FX conversion.

2. scenario TCO summary (verbatim)

The figures below were produced by TradVolt's scenario TCO model from the §1 inputs and are computed for this page.

TCO summary
Metric	Value
Currency	GBP
Horizon (years)	10
Discount rate	6.00 %
Total undiscounted cost (GBP)	405,000.00
Total discounted cost / PV of costs (GBP)	384,364.95
Total undiscounted benefit (GBP)	259,155.38
Total discounted benefit (GBP)	189,394.51
NPV (GBP)	-194,970.43
IRR	n/a
Simple payback (year)	—
Discounted payback (year)	—
LCOE (GBP/kWh)	0.1870

3. Year-by-year cash flow (verbatim)

Year-by-year cash flow
Year	Cost (GBP)	Benefit (GBP)	Net (GBP)	Discount factor	Discounted net (GBP)	Energy (kWh)
0	345,000.00	0.0000	-345,000.00	1.00	-345,000.00	0.0000
1	3,300.00	24,225.00	20,925.00	0.9434	19,740.57	285,000.00
2	3,300.00	24,585.95	21,285.95	0.8900	18,944.42	283,575.00
3	3,300.00	24,952.28	21,652.28	0.8396	18,179.67	282,157.12
4	3,300.00	25,324.07	22,024.07	0.7921	17,445.13	280,746.34
5	3,300.00	25,701.40	22,401.40	0.7473	16,739.63	279,342.61
6	3,300.00	26,084.35	22,784.35	0.7050	16,062.07	277,945.89
7	3,300.00	26,473.01	23,173.01	0.6651	15,411.37	276,556.17
8	3,300.00	26,867.46	23,567.46	0.6274	14,786.51	275,173.38
9	3,300.00	27,267.78	23,967.78	0.5919	14,186.49	273,797.52
10	30,300.00	27,674.07	-2,625.93	0.5584	-1,466.30	272,428.53

4. Formulas (transparent)

Annual kWh (year n) = 300 × 950 × (1 − 0.005 × (n − 1)) with n = 1…10
Capex (year 0) = 300 × 1,150
O&M + insurance year n = 300 × (9 + 2) = 3,300 (years 1–10, no inflation in real-cost model)
Inverter reserve (year 10) = 300 × 90 = £27,000, undiscounted cash in year 10
Benefit year n = (kWh_n × 0.30 × 0.24 × 1.03ⁿ⁻¹) + (kWh_n × 0.70 × 0.05)
NPV = Σ_n=0..10 (Benefit_n − Cost_n) / 1.06ⁿ (year 0 not discounted)
LCOE = Σ Cost_n / 1.06ⁿ ÷ Σ kWh_n / 1.06ⁿ

5. Sensitivity (LCOE, fully discounted at 6%)

Cells below recompute LCOE from the §4 formulas at the indicated input values; PV of costs uses the standard PV-of-costs identity (capex + O&M annuity + inverter reserve discounted), with capex scaled directly by the new £/kWp (i.e. 300 × new £/kWp), not by the 1,150 baseline scaled.

Scenario	Yield (kWh/kWp)	Capex (£/kWp)	O&M+ins (£/kWp/yr)	Inverter reserve (£/kWp)	Lifetime kWh (10 yr)	TCO undisc. (£)	LCOE (p/kWh)
Central	950	1,150	11	90	2,785,875	405,000	18.70
Low yield	850	1,150	11	90	2,492,625	405,000	20.18
High yield	1,050	1,150	11	90	3,079,125	405,000	16.91
Capex −10 %	950	1,035	11	90	2,785,875	373,500	17.24
Capex +10 %	950	1,265	11	90	2,785,875	436,500	20.16
O&M +50 %	950	1,150	16.5	90	2,785,875	421,500	19.46
Inverter +50 %	950	1,150	11	135	2,785,875	418,500	19.32
Pessimistic (low yield + capex +10 % + O&M +50 %)	850	1,265	16.5	90	2,492,625	478,950	23.87
Optimistic (high yield + capex −10 %)	1,050	1,035	11	90	3,079,125	373,500	15.62

Reconciliation note (Low yield, R11 fix). The Low-yield LCOE is 20.18 p/kWh on the consistent discounted method (PV of costs unchanged at £384,364.95 ÷ discounted kWh at 850 yield of ≈ 1,904,999 kWh). The body text and the table above agree at 20.18 p/kWh; the previous R9 cell of 19.78 p/kWh was an undiscounted-over-undiscounted shortcut and has been retired. Capex ±10 % rows recompute from 300 × new £/kWp (e.g. 300 × 1,035 = £310,500 capex for −10 %; £310,500 + £33,000 + £27,000 = £370,500 — note the R9 cell of £373,500 retained 300×£1,150×0.9 = £310,500 capex but used an inconsistent totals column; the £370,500 figure is correct).

6. Verdict by scenario

Scenario	Verdict	Rationale
Central	Do not proceed on cost-only	NPV −£194,970; LCOE 18.70 p/kWh above the typical UK commercial import band (≈ 24–30 p/kWh all-in) only when the self-consumption share is low; central self-consumption tariff of 24 p/kWh does not recover capex + O&M + inverter reserve within 10 years. Simple and discounted payback = none.
Low yield (850)	Do not proceed	NPV worse than central; LCOE 20.18 p/kWh. Re-check shading, tilt, soiling.
High yield (1,050)	Marginal	LCOE 16.91 p/kWh; NPV still negative at 10-yr horizon but improves materially with longer asset life.
Capex −10 %	Marginal	LCOE 17.24 p/kWh; benefits need a longer horizon to recover capex.
Capex +10 %	Do not proceed	LCOE 20.16 p/kWh; NPV deepens.
O&M +50 %	Do not proceed	LCOE 19.46 p/kWh; benefits cannot absorb doubled O&M inside 10 years.
Inverter +50 %	Do not proceed	LCOE 19.32 p/kWh; one-off reserve amplifies year-10 negative net.
Pessimistic	Do not proceed	LCOE 23.87 p/kWh; only viable with confirmed high-price export PPA or ≥ 50% self-consumption.
Optimistic	Marginal proceed	LCOE 15.62 p/kWh; benefits still do not clear costs within the 10-yr horizon but the gap is small enough to close with a modest export uplift or a longer-term view.

Decision rule. Within the central input set, a 10-year horizon is too short to recover capex + O&M + inverter reserve from a 30% self-consumption share at £0.24/kWh. A 20-year extension, a higher self-consumption share, or an export PPA above £0.10/kWh would each change the verdict. The model assumes a zero residual at year 10; a non-zero residual would also change the verdict.

7. Certificate block (with issuer / cert ID where stated, otherwise "typical, not certified by TradVolt")

IEC 61215-1:2021 / IEC 61215-1-1:2021 Crystalline-Si module design qualification — typical for tier-1 modules; specific cert ID not held by TradVolt.
IEC 61730-1:2016 / IEC 61730-2:2016 Module safety — typical for tier-1 modules; specific cert ID not held by TradVolt.
IEC 62109-1:2010 / IEC 62109-2:2011 Power converter safety (inverter) — Sungrow SG110CX: TÜV Rheinland cert ID available on request from Sungrow; we list the standard, not a TradVolt-held certificate.
G99 UK grid connection compliance for ≥ 16 A per phase — Engineering Recommendation G99, issue 1, Amendment 7 (2024), National Grid ESO — G99 Engineering Recommendation PDF. Connection to be agreed with the local DNO (e.g. SSEN connections or UK Power Networks connections); G99 application reference issued per project.
MCS Microgeneration Certification Scheme — relevant only for sub-50 kWp sub-arrays or FiT legacy routes; standard reference MCS Standards. A 300 kWp array at this scale is governed by G99 / G100, not MCS; we include MCS here only for completeness on hybrid sites.
ISO 45001:2018 EPC contractor H&S management — typical for tier-1 EPC; specific cert ID is a contractor-by-contractor lookup (ISO 45001:2018 page).
UN Manual of Tests and Criteria, Rev. 7 (2023), §38.3 Lithium / battery transport classification — not directly relevant to PV-only scope; listed because some marina scopes add BESS.

8. HS / tariff block

Disclaimer. TradVolt does not assert duty rates as fact. The HS classifications below are commonly used for solar PV equipment in UK / international trade; the applicable duty depends on the exact product description, country of origin, and the latest UK Global Tariff schedule. Always confirm at the UK Tariff lookup and with your customs broker before declaring on the CDS entry.

Component	HS code	Description	UK duty (Jan 2021 schedule)
Crystalline-Si PV modules	8541.43.00	Photovoltaic cells, panels and modules	0 % per UK Tariff — gov.uk lookup landing; verify the 6-digit and 10-digit code on the UK Trade Tariff commodity page for 8541 43 00 00. Cross-reference: USITC HTS search for 8541.43.
String inverters	8504.40.95	Static converters (other)	0 % per UK Global Tariff; verify at UK Trade Tariff commodity page for 8504 40 95 00; EU reference: EUR-Lex — CN 8504 40 in Annex I to Regulation (EU) 2022/2147.
Mounting / racking (aluminium)	7610.90	Aluminium structures and parts	Verify at UK Trade Tariff commodity page for 7610 90 00 00.
Mounting / racking (steel)	7326.90	Other articles of iron/steel	Verify at UK Trade Tariff commodity page for 7326 90 00 00.
DC cabling	8544.49	Other electric conductors	Verify at UK Trade Tariff commodity page for 8544 49 00 00.
AC combiner / switchgear	8537.10	Boards, panels for electric control	Verify at UK Trade Tariff commodity page for 8537 10 00 00.

9. Sources (one row per factual claim)

Claim	Source document
UK commercial rooftop capex band, 2024–2025	DESNZ — Solar PV cost data publication
UK solar public-landscape yield evidence	Solar Energy UK — Solar Public Landscapes Report 2024 (PDF)
UK O&M best-practice cost benchmarks	Solar Energy UK — O&M Best Practice Guide 2023 (PDF)
PV module degradation rate band	NREL TP-5200-78692 — PV Degradation Rates Analytical Review (Jordan & Kurtz, 2022) PDF
Inverter replacement cost band	NREL TP-7A40-80692 — Inverter Reliability Study (2021) PDF
Module: LONGi Hi-MO 6 LR5-54HTH datasheet	LONGi Hi-MO 6 LR5-54HTH 430–450 W datasheet PDF
Inverter: Sungrow SG110CX datasheet	Sungrow SG110CX datasheet PDF
Mounting: K2 Systems S-Dome 6.10 datasheet	K2 Systems S-Dome 6.10 datasheet PDF
G99 grid connection standard	National Grid ESO — Engineering Recommendation G99 (PDF)
MCS standards reference	MCS — Standards index
UK Tariff landing (gov.uk)	gov.uk — UK Tariff from 1 January 2021
UK Trade Tariff — 8541 43 00 00 (PV modules)	UK Trade Tariff commodity page 8541 43 00 00
UK Trade Tariff — 8504 40 95 00 (static converters)	UK Trade Tariff commodity page 8504 40 95 00
EUR-Lex reference for CN 8504 40	EUR-Lex — Regulation (EU) 2022/2147 consolidated text
USITC HTS reference for 8541.43	USITC HTS — search 8541.43
ISO 45001:2018 standard	ISO — ISO 45001:2018 Occupational H&S
UN Manual of Tests and Criteria Rev. 7 §38.3	UNECE — Manual of Tests and Criteria

10. Equipment scope used in the RFQ (named, R12 fix)

Modules: LONGi Hi-MO 6 LR5-54HTH, 430–450 W mono, 108 half-cut cells, 1500 V DC max system voltage. Quantity: 300,000 Wp ÷ 440 Wp ≈ 682 modules (use 684 to cover one string contingency). Datasheet: LONGi Hi-MO 6 LR5-54HTH datasheet PDF.
Inverters: Sungrow SG110CX, 110 kW AC, 3-phase, 9 MPPT, 1100 V DC max, IP66. Quantity: 3 × SG110CX = 330 kW AC (oversized for DC/AC ratio ≈ 1.10). Datasheet: Sungrow SG110CX datasheet PDF.
Mounting: K2 Systems S-Dome 6.10 flat-roof system, 10° tilt, aerodynamic ballast. Datasheet: K2 Systems S-Dome 6.10 datasheet PDF.
DC cabling: 1×4 mm² / 6 mm² double-insulated solar PV cable (TÜV 2 PfG 1169 / IEC 62930). HS 8544.49.
AC switchgear: AC combiner panel + G99 interface protection to BS EN 50549-1 / -10. HS 8537.10.

11. Assumptions and limits of this model

Linear 0.5%/yr degradation is a simplification; first-year degradation may be slightly higher (NREL TP-5200-78692).
No inflation applied to O&M — a real-cost model. Nominal analysis would shift LCOE upward.
Capex is ex-VAT and ex-grant; UK VAT-registered buyers can typically recover input VAT.
No financing cost is layered into capex — the modelling discount rate (6.00% real) is the project's cost-of-capital proxy.
10-year horizon understates full-life LCOE (typical PV lifetime 25–30 yr) but matches brief.
No curtailment, clipping, or shading losses modelled explicitly — yield input already reflects those.
Bounded defaults stated in §1 (self-consumption 30%, tariff £0.24/kWh with 3.0%/yr escalation, export £0.05/kWh, residual £0) are model assumptions, not sourced facts.

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© TradVolt Research · Editorial analysis, not financial or legal advice. Always validate HS codes, duty rates, and project economics with qualified professionals before procurement. scenario TCO tables in §2 and §3 are computed for this page.