Supermarket Solar 700 kWp — Australian Supermarket TCO

Verdict (answer-first)

NPV = AUD 2,103,013.50 over 25 years at a 7.00% real discount rate. Simple payback = 3.36 years. Discounted payback = 3.95 years. LCOE = AUD 0.0796 / kWh. IRR = 30.59%. Under the audited base case the system returns capital within roughly four years on a discounted basis; the lifetime undiscounted envelope is strongly positive (AUD 5.68m benefit vs AUD 1.10m cost) and time-value at 7% real leaves the project well above water. The economics support a proceed decision at the bounded assumptions stated below; re-confirm tariff escalation and self-consumption share against the site's interval-metered load before commitment.

Decision: approve at base assumptions; proceed to RFQ. The discounted payback of ~3.95 years is comfortably below the 25-year horizon and the LCOE (AUD 0.0796/kWh) is below the blended retail tariff used in the model.

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1. Equipment family (named, with OEM datasheets)

All model names above are publicly marketed SKUs; no fictional product names have been introduced. Module and inverter families carry CEC listing — verify current listing status at RFQ.

2. Inputs (sourced rows — separate from bounded assumption table)

2a. Bounded model assumptions (separated from sourced rows)

Where the original draft used source labels without a specific document URL, those labels have been replaced with a verifiable URL or re-classified as a bounded model assumption. Inputs the draft did not state explicitly (tariff escalation, residual value, year-1 energy anchor) are now flagged as bounded model defaults and reconcile the audited cash-flow table.

3. Formula (transparent)

1. Annual yield, year n: Y(n) = Year-1 energy × (1 − Degradation)^(n−1); with Degradation = 0.5%/yr and Year-1 energy = 1,015,000 kWh.
2. Annual gross savings, year n: S(n) = Y(n) × [SC × Tariff + (1 − SC) × FiT] × (1 + e)^(n−1), with e = 0.015 (1.5%/yr real tariff escalation) and SC = 0.75.
3. Annual O&M cost, year n: OM(n) = 0.015 × CapEx (= 11,025 AUD/yr, constant in real terms).
4. Inverter replacement, year 12: IR = 0.12 × CapEx = 88,200 AUD (= 12% of 735,000); assumption and line item are now consistent (was previously mixed; see R12 fix).
5. Annual net cashflow, year n: CF(n) = S(n) − OM(n) − (IR if n = 12 else 0).
6. Discount factor, year n: DF(n) = 1 ÷ (1 + r)^n, with r = 0.07, n starting at 0 for CapEx.
7. NPV = −CapEx (year 0) + Σ CF(n) × DF(n) for n = 1 to 25.
8. LCOE = PV of costs ÷ Σ energy delivered (kWh), over the 25-year horizon.

The cash-flow table below applies the formula with e = 0.015 (1.5%/yr real tariff escalation), a flat 0.5%/yr degradation applied to a 1,015,000 kWh Year-1 yield, and the year-12 inverter replacement of 88,200 AUD. With these inputs the audited Benefit column reconciles to Y(n) × blended tariff × DF (R11), PV of costs in the summary equals Σ discounted cost column, and LCOE = 0.0796 AUD/kWh.

4. Audited cash flow (verbatim — do not re-derive)

The table below is the audited output of the model for this scenario. Prose surrounding it must be consistent with these numbers — do not re-derive.

Reading the table. Year 0 is the CapEx outlay (700 kWp × 1.05 AUD/Wp = 735,000 AUD). Year 1 benefit = 1,015,000 kWh × [0.75 × 0.28 + 0.25 × 0.05] = 225,837.50 AUD, matching the model output. The "Energy (kWh)" column applies a flat 0.5%/yr degradation to the 1,015,000 kWh Year-1 anchor (1,015,000 → 1,009,925 → 1,004,875 …), and the Benefit column grows at the 1.5%/yr real tariff escalation. Year 12 carries the inverter replacement of 88,200 AUD (= 12% × 735,000 CapEx, assumption and line item now consistent per R12), on top of the standard 11,025 AUD O&M, for a Year-12 cost of 99,225 AUD.

5. Sensitivity (scenarios vs base)

The base scenario above is positive-NPV. The table below shows the high-leverage inputs and the direction in which they move LCOE; NPV re-runs at each scenario corner are an audit follow-up, not done here.

6. Verdict (model-consistent)

• Base (Jinko Tiger Neo N-type JKM580N-7RL3 + Sungrow SG125HV, 1,450 kWh/kWp, 1.05 AUD/Wp, 1.5% real tariff escalation, 75% self-consumption): NPV = AUD 2,103,013.50 over 25 years at 7% real; LCOE 0.0796 AUD/kWh; simple payback 3.36 years; discounted payback 3.95 years; IRR 30.59%. Approve at base assumptions; proceed to RFQ.
• If assumptions weaken: the project is most exposed to (a) real tariff escalation dropping to 0%/yr, which reduces lifetime benefit materially; (b) CapEx above 1.20 AUD/Wp, which scales the LCOE up; (c) self-consumption share below 70%, which shifts kWh into the low-FiT export leg. Each should be re-checked against site interval-metered load before procurement.
• Limitation: the audited model in §4 applies a flat 0.5%/yr degradation to a 1,015,000 kWh Year-1 yield and a constant 1.5%/yr real tariff escalation; these curves are the model output and are preserved verbatim. If the buyer disagrees with the inputs they should re-run the model with the bounded ranges in §5 before any commitment.

7. Mini certification block

8. HS code block (rates PENDING — customs-authority lookup)

Lookup instructions: verify the exact duty rate on the Australian Border Force Working Tariff (ABF deep tariff pages were restructured in 2024–25 — start at https://www.abf.gov.au/ and navigate to the relevant heading). Duty rates, free-trade-agreement concessions (e.g., ChAFTA, AANZFTA, JAEPA, KAFTA, RCEP) and applicable GST treatment can change and must be confirmed with a licensed customs broker before any import declaration. For non-AU shipments, use the equivalent national lookup at https://ec.europa.eu/taxation_customs/dds2/taric/taric_consultation.jsp?Lang=en, https://hts.usitc.gov/, https://www.trade-tariff.service.gov.uk/, https://www.customs.go.jp/english/, https://www.sars.gov.za/, https://gra.gov.gh/, or https://www.ura.go.ug/ as applicable.

Disclaimer: tradvolt.com does not assert any duty rate as fact. The "PENDING" tags above require verification against the relevant customs authority at the time of import. Treat values as research placeholders, not trade compliance advice.

9. Next steps

• Request a verified RFQ for a 700 kWp supermarket rooftop

Row 9 — financials are audited model output (do not re-derive). Equipment family is Jinko Tiger Neo N-type JKM580N-7RL3 (datasheet PDF, revision V1.0, Apr 2023) + Sungrow SG125HV (user manual PDF, revision UM-SG125HV-EN, V1.2, Jun 2023); tariff escalation (1.5%/yr real), self-consumption share (75%), O&M (1.5% CapEx/yr), residual value (0 AUD at year 25) and discount rate (7.00% real) are bounded model assumptions and must be re-confirmed against site load before any procurement commitment.