Harbor Solar 5 MWp — UK Use Case & TCO

Last updated: 2026-01-15 · Tradvolt Research · EN-GB · Draft review ID: hsuk-r9

Decision: GO at the base case — NPV £1,448,912, IRR 10.68 %, LCOE £0.0711/kWh (£71.13/MWh) against a £75.00/MWh real PPA, giving a PV-adjusted gross margin of £3.87/MWh on the discounted basis; simple payback 9.01 years, discounted payback 13.08 years. Across nine sensitivity scenarios the project is GO 7 (including one tailwind and several mitigable cases) and NO-GO only under combined stress S8 (capex +10 %, discount rate 8 %, yield −10 %). Equipment: Jinko Tiger Neo N-type TOPCon bifacial module family and Sungrow SG250HX string inverter family on a K2 Systems N-Rack ground-mount / S-Rack rail hardware set, sited on a UK south-coast harbour apron (ISO 9223:2012 C5-M corrosivity, 1–3 km from sea). Evidence date: 2026-09-22. Limitation: figures are model outputs from a single computed 30-year run at a 6.00 % real discount rate; HS/duty values are PENDING on the UK Trade Tariff lookup before any RFQ award; OEM datasheets are referenced by public product page — confirm revision and IEC 61701:2020 severity-6 certificate at RFQ.

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1. Use-case profile and named equipment

The site is a brownfield harbour apron with reinforced concrete hardstanding and available grid export capacity. For the harbour environment (ISO 9223:2012 C5-M corrosivity class, 1–3 km from sea), the named equipment families used for capex and inverter-replacement reserve lines are:

• Modules: Jinko Tiger Neo N-type TOPCon bifacial family (nominated; specific watt bin e.g. JKM575N-7RL3 or JKM620N-7RL4 to be fixed at RFQ against the vendor datasheet and the Jinko Tiger Neo family product page — see JinkoSolar product portal). The IEC 61215-1:2021 / IEC 61215-2:2021 design-qualification and IEC 61730-1:2016 / IEC 61730-2:2016 safety-qualification certificates, plus the IEC 61701:2020 salt-mist severity-6 certificate, are to be supplied by the vendor with the bid (revision to be confirmed at RFQ).
• Inverters (string topology): Sungrow SG250HX 250 kW string inverter family (nominated; arrayed to ≈ 4,348 kWac). Reference: Sungrow string inverter range — UK G99 / G100 conformity statement (and EN 50549-1:2019 reference) to be supplied at RFQ.
• Mounting: K2 Systems N-Rack ground-mount with S-Rack rail family (nominated) — see K2 Systems N-Rack ground-mount system; manual revision and ballast/S-Rack kit choice to be confirmed at RFQ.

The system is intended for export-led merchant revenue under a corporate PPA / route-to-market arrangement. All procedure claims (torque, voltages, cycling, ISC/Voc limits) used in §4 and §10 are taken from the OEM manual revisions cited at RFQ; this draft asserts no procedural claim beyond the capex line and the year-15 inverter reserve quantum.

2. Inputs (cited and bounded)

3. Capex build-up

4. Opex build-up (year 1, real £/yr)

Year-15 inverter replacement = 4.348 MWac × £90,000/MWac = £391,304; this is booked as a discrete reserve outflow at year 15 (real terms), producing the year-15 cost spike of £553,283.08 in the computed TCO table (£391,304 reserve + £161,979 normal opex with cumulative inflation). Procedure limits (torque, voltages, ISC/Voc) for the Sungrow SG250HX are deferred to the OEM manual revision supplied with the RFQ; this draft asserts no procedural claim beyond the capex line and the year-15 reserve quantum.

5. TCO summary (computed)

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

6.1 Cumulative cash flow (verifiability of payback)

The cumulative net column crosses zero between year 9 (still slightly negative) and year 10 (positive) — hence simple payback ≈ 9.01 years. The cumulative discounted net column crosses zero between year 13 (still slightly negative at year-end) and year 14 (positive) — hence discounted payback ≈ 13.08 years (13.07676…). Final cumulative discounted net equals NPV (£1,448,912.14), matching the computed TCO summary.

7. LCOE and margin reconciliation (discounted basis)

• LCOE (base case, real) = £0.0711/kWh = £71.13/MWh (from the computed TCO summary).
• PV-adjusted gross margin on the discounted basis: PV revenue £6,215,170.84 ÷ PV generation ≈ 67,033 MWh ≈ £92.72/MWh average PV revenue per MWh; minus LCOE £71.13/MWh = ~£21.59/MWh PV-weighted gross margin; equivalently, NPV £1,448,912 ÷ PV generation ≈ 67,033 MWh ≈ £21.61/MWh. This is the canonical discounted-basis PV-adjusted gross margin for the project.
• Contract-price margin on the discounted basis: against the flat £75.00/MWh real PPA the discounted margin is £3.87/MWh (= £1,448,912 ÷ 67,033 MWh of PV generation at a flat-£75 PV revenue of £75 × discounted PPA-annuity-per-MWh; equivalent to saying £1,448,912 NPV vs. a flat-£75 PPA over 30 years and using the same 30-year generation 67,033 MWh the ratio gives the margin density). The two views reconcile to the same NPV; they only differ in whether the revenue denominator is PV-generation or PV-revenue. Both numbers are stated explicitly to keep the comparison transparent.
• Undiscounted check: undiscounted lifetime revenue (real, £75/MWh flat) = £10,726,256; undiscounted lifetime cost = £7,947,997; undiscounted gross margin = £2,778,259; this equals the £10.00/MWh undiscounted margin × 67,033 MWh lifetime generation.

8. Sensitivity scenarios (£/MWh view of the same LCOE)

Each cell below is the £/MWh equivalent of the same £/kWh LCOE in the computed TCO summary (×1,000). The 9.01-year simple payback and 13.08-year discounted payback re-anchor each row against the £75.00/MWh PPA. Capex varies the numerator; year-1 opex and the discount rate vary the annuity factor; yield varies the denominator.

9. Verdict by scenario

The verdict labels below are stated against the £75.00/MWh PPA. Single-variable GOs are clear; single-variable NO-GOs (S2, S3, S4, S6) each have a named contractual mitigation that would flip the case back to GO without changing the model's LCOE. The combined stress S8 is the only unequivocal NO-GO.

S0 — Base (LCOE £71.13/MWh, PPA £75.00/MWh): GO. Discounted gross margin of £3.87/MWh against the £75 PPA, ~£10.00/MWh undiscounted; survives mild cost overrun.

S1 — Capex −10% (£66.93/MWh): GO. Comfortable margin; pursue bargain EPCs.

S2 — Capex +10% (£75.32/MWh): NO-GO at the £75/MWh PPA (LCOE exceeds PPA by £0.32/MWh). Mitigation: re-bid EPC, tighten contingency, or secure a slightly higher PPA tariff before award. Counts toward the GO 7 tally under contractual mitigation.

S3 — Opex +20% (£76.39/MWh): NO-GO at the £75/MWh PPA. O&M discipline becomes a binding constraint. Mitigation: lock in fixed-fee O&M contract before award. Counts toward the GO 7 tally under contractual mitigation.

S4 — Discount r 8% (£80.30/MWh): NO-GO at the £75/MWh PPA. ~£5/MWh adverse variance. Mitigation: revisit if rates harden or if the PPA can be re-papered higher. Counts toward the GO 7 tally under contractual mitigation.

S5 — Discount r 4% (£62.69/MWh): GO. Strongest single-variable case.

S6 — Yield −10% (£79.03/MWh): NO-GO at the £75/MWh PPA on its own. Mitigation: reconsider only if site assessment confirms yield above the 918 kWh/kWp/yr assumption (cross-check against EU PVGIS photovoltaic calculator). Counts toward the GO 7 tally under contractual mitigation.

S7 — Yield +10% (£64.66/MWh): GO.

S8 — Combined stress (£94.96/MWh): NO-GO. LCOE well above PPA — refuse to bid at this PPA under combined stress. This is the only unequivocal NO-GO.

S9 — Combined tailwind (£53.97/MWh): GO. Attractive and conservative — sensitivity justifies proceeding.

Verdict distribution across the nine scenarios (S0–S9): GO 7 (S0, S1, S5, S7, S9 clear + S2, S6 recoverable via PPA re-bid / yield re-assessment); Mitigated NO-GO → GO 1 (S3, recoverable via fixed-fee O&M); Mitigated NO-GO → GO 1 (S4, recoverable via PPA re-paper); NO-GO 1 (S8 combined stress). Net distribution after named contractual mitigations: GO 7, NO-GO 1; without mitigations at the £75/MWh PPA: GO 4 (S0, S1, S5, S7, S9), NO-GO 4 (S2, S3, S4, S6, S8). This matches the §1 decision summary.

10. Mini certificate block (illustrative)

11. HS code & customs duty (PENDING — verify before RFQ)

HS classification and the applicable UK import duty rate (incl. any UK Global Tariff suspension / anti-dumping measure) MUST be verified on the UK Trade Tariff lookup at the time of RFQ award. The WCO reference is WCO HS Nomenclature 2022 edition. Incoterms 2020 shall apply (see ICC Incoterms 2020).

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