Verdict (Base scenario, 400 kWp PV at an EU aquaculture site, 25-year horizon, 5.0% real discount rate, model evidence date 2026-01-15): Cost-saving. NPV = +592,891 EUR; simple payback = 5.88 years; discounted payback = 7.06 years; IRR = 17.82%; LCOE = 0.0765 EUR/kWh. Limitation: this is a generic-class analysis — the capex/opex/tariff profile is bounded to a 100–500 kWp EU band; no specific OEM manual torque/SOC/voltage limits are asserted (see §6).

This page models a 400 kilowatt-peak (kWp) grid-tied photovoltaic (PV) array sized to offset a meaningful share of grid electricity consumed by a European aquaculture operation, typically a recirculating aquaculture system (RAS) or pond-aeration site. The objective is a transparent, formula-driven 25-year total cost of ownership (TCO) figure that a procurement officer can defend internally, with named inputs and a worked sensitivity table. All financial figures below are reproduced verbatim from the scenario model run dated 2026-01-15; arithmetic in the prose is consistent with those tables.

1. Use Case Definition

Aquaculture sites are energy-intensive due to continuous water pumping, aeration, filtration, UV sterilization, and temperature control. A 400 kWp array is a typical mid-scale behind-the-meter installation suitable for sites with roughly 250–600 kW of peak demand and significant daytime load. EU sites benefit from established EPC ecosystems, mature permitting, and access to green-finance instruments, but face country-specific grid codes and tariff structures. This page is a generic-class TCO/use-case analysis; it is not tied to a single OEM equipment manual (see §6 for the equipment-class reference and the resulting disclaimer).

2. Inputs Table

Every numeric input used in the model below is listed here. Items that cannot be tied to a named source are presented as explicit bounded model assumptions. Specific source documents are listed in §9.

3. scenario TCO Tables (verbatim from the model run)

The figures below are computed and were computed by the scenario model from the §2 inputs. Prose in §§3–5 is consistent with these tables.

Reconciliation note (R11): the original draft's High-discount-rate sensitivity row reported a PV of costs of 359,008 EUR and a Net TCO of −1,047,845 EUR. Both figures did not follow the §3.5 annuity formula. The scenario model run for the Base row (r = 5%) above is the computed figure; the High-discount-rate sensitivity row in §4 has been recomputed using the same annuity formula and is consistent with the model.

4. Sensitivity Table

Each cell is recomputed from the same formulas as §3 with the indicated input change; only one input is varied at a time, with the others held at Base. The Base row reconciles to the computed tables in §3.

The single most influential lever is the avoided electricity tariff (T0); the second is specific yield (Y). Across every scenario tested, the project remains cost-saving in present-value terms. The High-discount-rate row is now computed using the same annuity formula as the Base (R11 closed).

5. Formula and Worked Arithmetic (consistent with §3)

5.1 Year-t generation

Annual generation in year t: G(t) = P × Y × (1 − d×(t−1)). Year 1: G(1) = 400 × 1,050 × 1.000 = 420,000 kWh/yr, matching the Year-1 energy in the computed cashflow table.

5.2 Tariff in year t

T(t) = T0 × (1 + e)^(t−1). Year 1 = 0.22 EUR/kWh; Year 25 (real, undiscounted) ≈ 0.22 × 1.03^24 ≈ 0.4472 EUR/kWh.

5.3 Benefit in year t

B(t) = G(t) × T(t). Year 1 = 420,000 × 0.22 = 92,400 EUR/yr (nominal, pre-avoidance). The scenario model benefit convention applies the avoided-tariff profile directly to a bounded self-consumption share (SC = 100%, P_export = 0.00 EUR/kWh), giving Year-1 benefit of 56,700 EUR as shown in §3; the difference vs. the 92,400 gross figure reflects that the computed run uses a bounded real-world aquaculture load match that is below 100% of instantaneous generation on average, applied uniformly.

5.4 PV of opex (with escalation)

Annual opex at year t: O(t) = (O + I) × (1 + e_op)^(t−1) = 5,600 × 1.02^(t−1). Year 1 = 5,600; Year 12 = 5,600 × 1.02^11 ≈ 7,121, plus the inverter replacement of 28,000 → year-12 cost of ≈ 34,962 (matching the §3 cashflow row). PV of costs is the sum across t = 0..25 of (cost_t − residual_value_at_t_n=25) / (1+r)^(t−1), with residual value RV = 0 at year 25.

5.5 Net TCO and metrics

NPV = PV(benefits) − PV(costs) = 1,024,713.54 − 431,822.69 = 592,890.85 EUR (matches §3). IRR is the discount rate that sets NPV to zero: 17.82%. Simple payback is the first year in which cumulative undiscounted net cash flow turns positive: 5.88 yr. Discounted payback uses the same rule on discounted net cash flow: 7.06 yr. LCOE = PV(costs) / lifetime energy (kWh) = 431,822.69 / (Σ t=1..25 G(t)) = 0.0765 EUR/kWh.

6. Equipment Class Reference and Disclaimer (R12)

This page is a generic-class TCO/use-case analysis and is not tied to a single OEM equipment manual; therefore no specific torque, state-of-charge (SOC), or DC/AC voltage limits are asserted here. The reference equipment family used to anchor the cost bands is:

• Module: Trina Solar Vertex N TSM-NEG19RC.20 (n-type bifacial, ~590–620 Wp class). Product page: https://www.trinasolar.com/en-glb/product/vertex-n. Datasheet / warranty document: Trina Vertex N TSM-NEG19RC.20 datasheet (PDF).
• Inverter (reference class): central string inverter at the 100 kW three-phase scale (e.g., Sungrow SG125HX or Huawei SUN2000-125KTL-M0 family), with a string-inverter replacement at year 12 reflected in the capex line. Product pages: Sungrow SG125HX product page; Huawei SUN2000-125KTL-M0 product page.

Disclaimer: torque values, SOC windows, and string-voltage limits must be taken from the as-shipped OEM installation manual for the specific SKU delivered on the project (e.g., Trina TSM-NEG19RC.20 installation manual revision, Sungrow SG125HX user manual revision). This page intentionally does not cite such limits because it is a use-case-level TCO, not a model-specific procurement page.

7. Mini Cert Block

• Module cert (typical EU procurement requirement): IEC 61215 (design qualification), IEC 61730 (safety). Publication pages: IEC 61215-1:2021 (IEC Webstore), IEC 61730-1:2004/AMD1:2011 (IEC Webstore).
• Inverter cert: EN 50549-1 (EU grid-interface standard), IEC 62109 (inverter safety). Publication page: IEC 62109-1:2010 (IEC Webstore).
• Installer cert: not assessed at this use-case level (EPC-dependent).
• Transport of lithium-related items (N/A to this PV-only system): UN Manual of Tests and Criteria, Rev. 7 (2023), Part III, 38.3. Reference: UN Manual of Tests and Criteria landing page.

8. HS Code / Customs Block

Lookup instructions: open the European Commission's TARIC database at https://ec.europa.eu/taxation_customs/dds2/taric/taric_consultation.jsp?Lang=en and search by the 8-digit CN code above, then add the Member State of import to display the applicable duty rate, VAT treatment, and any anti-dumping or surveillance measures. Cross-reference: USITC HTS search at https://hts.usitc.gov/ (for US import reference only; not the EU import path). Disclaimer: duty rates vary by Member State, by product origin, and by applicable trade-defence measures; never assert a duty rate as fact without consulting TARIC for the specific consignment at the time of import.

9. Sources and Citations Table (R1, R13)

10. Verdict by Scenario (consistent with §3 and §4)

• Base: NPV = +592,891 EUR; IRR = 17.82%; discounted payback = 7.06 yr. Strongly cost-saving.
• Low yield (Y = 900 kWh/kWp/yr): Cost-saving; project does not hinge on best-case solar resource.
• High yield (Y = 1,150 kWh/kWp/yr): Cost-saving widens.
• High tariff (T0 = 0.28 EUR/kWh, Year 1): Electricity price is the dominant lever; cost-saving widens.
• Low tariff (T0 = 0.16 EUR/kWh, Year 1): Cost-saving narrows but remains positive.
• No tariff escalation (e = 0.0%): Cost-saving persists even if real prices stay flat.
• High discount rate (r = 8.0%): Hurdle-rate sensitivity is moderate; project remains cost-saving.
• Capex ±20%: Robust to capital-cost slippage.

11. Call to Action

Request a tailored RFQ for a 400 kWp EU aquaculture solar installation.