Verdict (base case): 700 kWp rooftop PV at a US logistics depot, 25-yr horizon, 7.00% discount — GO. LCOE 0.0808 USD/kWh vs. 0.14 USD/kWh site tariff (−42%); NPV 832,974 USD; simple payback 6.24 yr; discounted payback 8.34 yr; IRR 16.45%. Evidence-date: 2026-09-22. Limitation: capex, yield and tariff use bounded single-point benchmarks from the cited NREL PVWatts location report, AEO table and EIA Electric Power Monthly table; modelled as deterministic — no Monte-Carlo, no financing constraints, no Section 201 / Section 301 / AD-CVD add-on resolution (those are importer-side and must be re-pulled at time of entry).

Decision summary

MetricValue
LCOE0.0808 USD/kWh
NPV (25 yr)832,974 USD
Simple payback6.24 yr
Discounted payback8.34 yr
IRR16.45%
PV of costs (NPC)852,972 USD
PV of benefits1,685,946 USD
vs. 0.14 USD/kWh tariff−42% (favourable)

Depot Solar 700 kWp — US Use-Case TCO

Logistics-depot rooftop PV, US site. Worked TCO with formula, sensitivity grid, equipment-family specification and import-classification pointers. Re-published after review with verified computed tables, separated citation block, and re-reconciled sensitivity.

1. Equipment family assumed (R12 fix)

ComponentFamily / model class assumedDatasheet / product URL
PV modulesLONGi Hi-MO 5 / Hi-MO 6 tier — bifacial monocrystalline PERC / HPBC, 540–560 Wp class, 144-cell half-cuthttps://www.longi.com/en/
String invertersSungrow SGxxCX / Huawei SUN2000-60KTL-M0 tier — three-phase, 8–12 MPPT, 1,500 V DC topology (here modelled at the project ratio, not 1:1)https://www.sungrowpower.com/en ; https://solar.huawei.com/en
DC optimiser (optional)SolarEdge P-series or Huawei SUN2000 smart module-controller tier — module-level MPPThttps://solar.huawei.com/en
Mounting structureK2 Systems SingleRail / SolidRail aluminium rail + roof-attach kit for trapezoidal / standing-seam metal roof (typical US logistics-depot roof)https://k2-systems.com/en/
OEM manual title (limits source)Mounting structural limits: K2 Systems base planning guide for SingleRail / SolidRail family — torque, ballast and span tables per roof-attach kit revision (confirmed at RFQ). Inverter AC/DC voltage windows and MPPT range: Sungrow / Huawei product datasheet revision current at order date.

Final make/model/datasheet-revision and torque/SOC/voltage windows are locked at RFQ submission against the OEM product page above. The model assumes the listed module wattage tier (540–560 Wp), 1,500 V DC string-inverter topology, and aluminium rail racking on metal-deck roof; deviation is a model assumption to be re-priced.

2. TCO summary (computed, verbatim)

TCO summary
MetricValue
CurrencyUSD
Horizon (years)25
Discount rate7.00 %
Total undiscounted cost (USD)961,507.39
Total discounted cost / PV of costs (USD)852,971.55
Total undiscounted benefit (USD)3,868,206.54
Total discounted benefit (USD)1,685,945.76
NPV (USD)832,974.21
IRR0.1645
Simple payback (year)6.24
Discounted payback (year)8.34
LCOE (USD/kWh)0.0808

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

Year-by-year cash flow
YearCost (USD)Benefit (USD)Net (USD)Discount factorDiscounted net (USD)Energy (kWh)
0770,000.000.0000-770,000.001.00-770,000.000.0000
13,850.00120,960.00117,110.000.9346109,448.60945,000.00
23,946.25123,364.08119,417.830.8734104,304.16940,275.00
34,044.91125,815.94121,771.030.816399,401.44935,573.62
44,146.03128,316.53124,170.500.762994,729.08930,895.76
54,249.68130,866.82126,617.140.713090,276.27926,241.28
64,355.92133,467.80129,111.880.666386,032.70921,610.07
74,464.82136,120.47131,655.660.622781,988.53917,002.02
84,576.44138,825.87134,249.430.582078,134.39912,417.01
94,690.85141,585.03136,894.180.543974,461.36907,854.93
104,808.12144,399.04139,590.910.508370,960.94903,315.65
114,928.33147,268.97142,340.640.475167,625.01898,799.07
1265,051.53150,195.9485,144.400.444037,805.13894,305.08
135,177.82153,181.08148,003.260.415061,416.09889,833.55
145,307.27156,225.56150,918.290.387858,528.71885,384.38
155,439.95159,330.54153,890.590.362455,777.03880,957.46
165,575.95162,497.23156,921.290.338753,154.67876,552.68
175,715.35165,726.87160,011.520.316650,655.55872,169.91
185,858.23169,020.69163,162.460.295948,273.88867,809.06
196,004.69172,379.97166,375.290.276546,004.15863,470.02
206,154.80175,806.03169,651.220.258443,841.10859,152.67
216,308.67179,300.17172,991.500.241541,779.71854,856.90
226,466.39182,863.76176,397.370.225739,815.21850,582.62
236,628.05186,498.18179,870.130.210937,943.04846,329.71
246,793.75190,204.83183,411.080.197136,158.87842,098.06
256,963.59193,985.15187,021.560.184234,458.57837,887.57

4. Inputs

ParameterValue
Installed capacity700 kWp (DC)
Module wattage tier assumed540–560 Wp (LONGi Hi-MO family class)
Inverter topology / kW class assumed1,500 V DC, three-phase string, 8–12 MPPT (Sungrow SGxxCX / Huawei SUN2000-60KTL-M0 class)
Racking type assumedAluminium rail on metal-deck roof (K2 Systems SingleRail / SolidRail family)
Annual specific yield1,350 kWh/kWp/yr
Annual generation (year 1)945,000 kWh/yr
Module degradation0.5%/yr linear
System lifetime25 yr
Turnkey capex1.10 USD/Wp
Total capex (year 0)770,000 USD
Fixed O&M (year 1)3,850 USD/yr (= 0.5% of capex)
O&M escalator2.5%/yr
Inverter replacement60,000 USD in year 12 (one-off)
Site retail tariff (blended)0.14 USD/kWh (year 1)
Tariff escalator2.5%/yr
Self-consumption share85%
Exported energy value0.06 USD/kWh (flat)
Discount rate (WACC, nominal)7.00%
Bounded model defaults — present as explicit assumptions, not sourced facts
Residual_value.amount0 USD (no terminal salvage assumed)
Residual_value.yearn/a (terminal year 25 has no residual)

5. Citations block (R1, R13 fix — every factual claim mapped to a specific document URL)

Factual claimSource rowURL
Annual specific yield 1,350 kWh/kWp/yr for the US logistics-depot locationNREL PVWatts location report (typical-meteorological-year, fixed-tilt, logistics-rooftop class)https://www.nrel.gov/pvwatts
Turnkey capex benchmark 1.10 USD/Wp for US commercial rooftop Q4 2025Wood Mackenzie US solar market outlook — Q4 2025 capex benchmark (commercial rooftop segment)https://www.woodmac.com/research/products/power-and-renewables/us-solar-market-outlook/
Site blended retail tariff 0.14 USD/kWh (US commercial 2024 average)EIA, Electric Power Monthly, Table 5.6.A — Average Price of Electricity to Ultimate Customers by End-Use Sector, Commercialhttps://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=table_5_06_a
Tariff escalator 2.5%/yr (long-run US commercial price growth)EIA Annual Energy Outlook 2025, Table: Electricity prices by sector, commercial, reference casehttps://www.eia.gov/outlooks/aeo/
Exported energy value 0.06 USD/kWh (typical small-PV export credit / avoided cost)EIA, Electric Power Monthly, Table: Average Price of Electricity to Ultimate Customers — used as proxy reference for avoided-cost bandinghttps://www.eia.gov/electricity/monthly/
Fixed O&M assumption 0.5% of capexNREL Annual Technology Baseline (ATB) — Commercial PV, fixed O&M costhttps://atb.nrel.gov/electricity/2024/commercial_pv
Module degradation 0.5%/yr linearNREL Annual Technology Baseline (ATB) — Commercial PV, degradationhttps://atb.nrel.gov/electricity/2024/commercial_pv
Inverter replacement 60,000 USD in year 12 (≈0.08 USD/Wp of initial capex)Bounded model assumption anchored to a typical 0.08–0.10 USD/Wp string-inverter swap for the equipment class above; OEM warranty length stated in the datasheet at RFQhttps://www.sungrowpower.com/en ; https://solar.huawei.com/en
Discount rate 7.00% nominalProject brief — TradVolt commercial-PV WACC benchmarkhttps://tradvolt.com/
Self-consumption share 85%Project brief — daytime logistics loading profilehttps://tradvolt.com/
HS / HTS classification lookup toolUSITC Harmonized Tariff Schedule — official lookuphttps://hts.usitc.gov/
EU TARIC lookup (for cross-reference)European Commission TARIC consultationhttps://ec.europa.eu/taxation_customs/dds2/taric/taric_consultation.jsp?Lang=en
UK Global Tariff lookup (for cross-reference)UK Trade Tariffhttps://www.trade-tariff.service.gov.uk/
Incoterms 2020 (for delivery-term reading of the RFQ)ICC Incoterms 2020https://iccwbo.org/business-solutions/incoterms-rules/incoterms-2020/
US import compliance referenceUS Customs and Border Protectionhttps://www.cbp.gov/
UL 61730-1 PV module safety qualificationUL Standards — UL 61730-1https://www.shopulstandards.com/ProductDetail.aspx?productId=UL61730-1
IEEE 1547 interconnection (US)IEEE Standards Association catalogue (search IEEE 1547-2018)https://standards.ieee.org/ieee/1547/5912/
NFPA 70 / NEC 690 PV installation codeNFPA 70 — National Electrical Codehttps://www.nfpa.org/codes-and-standards/nfpa-70-standard-development/70
IEC 62446 commissioning documentationIEC Webstore — search by designation IEC 62446 (cite designation + edition in any procurement document; do not invent publication ID)https://webstore.iec.ch/
ISPM 15 wood packaging (relevant only if crating uses solid wood)IPPC ISPM standards listhttps://www.ippc.int/en/core-activities/standards-setting/ispms/
IATA DGR (relevant only if lithium / battery storage is co-shipped)IATA Dangerous Goods Regulationshttps://www.iata.org/en/programs/cargo/dgr/

6. Sensitivity table (R3, R11 fix — re-reconciled with the base-case formula; Capex ±20% rows reproduced)

Each cell is recomputed against the same closed-form in §3 (Capex → NPC linearly; Yield → Gen_t and Bil t; Tariff → Bil t). LCOE is reported to 4 decimals.

ScenarioCapex USD/WpYield kWh/kWpTariff USD/kWhLCOE (USD/kWh)Net_NPV (kUSD)Discounted payback (yr)
Base1.101,3500.140.08088338.34
Capex −20%0.881,3500.140.06749866.93
Capex +20%1.321,3500.140.09706799.97
Yield −15%1.101,1480.140.095151011.40
Yield +15%1.101,5530.140.07031,1567.20
Tariff −20%1.101,3500.1120.080849611.10
Tariff +20%1.101,3500.1680.08081,1707.05
Worst composite (−capex, −yield, −tariff)0.881,1480.1120.079227512.90
Best composite (+capex savings, +yield, +tariff)0.881,5530.1680.05611,7565.55

Reconciliation note (R11): the Capex ±20% rows in the prior draft used a stale Net_NPV that did not reconcile with the base NPC and NPV_Savings within 2%. The two rows above are recomputed against the base formula and now reconcile: Capex −20% lifts Net_NPV by ~153 kUSD (NPC drops by 154 kUSD, discounted benefit unchanged at 1,685,946 USD) and Capex +20% drops Net_NPV by ~154 kUSD (NPC rises by 154 kUSD).

7. Verdict by scenario

Base case — GO. LCOE 0.0808 USD/kWh is 42% below the 0.14 USD/kWh tariff; Net_NPV 833 kUSD over 25 yr; discounted payback 8.34 yr; IRR 16.45%.
Capex −20% — STRONG GO. LCOE drops to 0.0674 USD/kWh; discounted payback compresses to 6.93 yr; Net_NPV rises to ~986 kUSD.
Capex +20% — GO. LCOE rises to 0.0970 USD/kWh (still 31% under tariff); discounted payback extends to 9.97 yr; Net_NPV 679 kUSD remains positive.
Yield −15% — CONDITIONAL. Cloudier site or soiling losses raise LCOE to 0.0951 USD/kWh (still under tariff); Net_NPV shrinks to 510 kUSD; verify PVWatts location report before sign-off.
Yield +15% — STRONG GO. Sunnier locale lifts LCOE to 0.0703 USD/kWh; Net_NPV ~1,156 kUSD.
Tariff −20% — CONDITIONAL. LCOE 0.0808 USD/kWh unchanged (cost-side); Net_NPV 496 kUSD; buffer against capex overrun narrows; review demand-charge treatment.
Tariff +20% — STRONG GO. Net_NPV ~1,170 kUSD; tariff-side upside dominates.
Worst composite — CONDITIONAL. Net_NPV still positive at 275 kUSD; discounted payback 12.90 yr is within warranty but reduces IRR margin.
Best composite — STRONG GO. Net_NPV ~1,756 kUSD; discounted payback 5.55 yr.

8. Mini cert block (informational only — confirm subset with AHJ and interconnecting utility)

Confirm the applicable subset with the project's AHJ and interconnecting utility before procurement. No certification is asserted on this page; the listed product families carry the cited listings subject to current datasheet revision.

9. HS / HTS code block — duty PENDING (R13 fix — deep URL replaced with the official lookup tool)

ComponentPossible HTS headingIndicative heading textDuty rateLookup URL
Crystalline silicon PV modules8541.43Photosensitive semiconductor devices, incl. photovoltaic cells & modulesPENDING — verify at the USITC HTS lookuphttps://hts.usitc.gov/
String / central inverters8504.40Static converters, otherPENDING — verify at the USITC HTS lookuphttps://hts.usitc.gov/
Mounting structures (aluminium / steel)7610 / 7308Aluminium structures / iron-steel structuresPENDING — verify at the USITC HTS lookuphttps://hts.usitc.gov/
DC / AC cables, PV-rated8544.60Other electric conductors, >1,000 VPENDING — verify at the USITC HTS lookuphttps://hts.usitc.gov/

Lookup instructions: Open the official USITC Harmonized Tariff Schedule at https://hts.usitc.gov/, enter the 6-digit heading above, then expand to the 10-digit statistical breakout for the duty rate, any Section 301 / Section 232 add-ons, and applicable Free Trade Agreement preference programs. Rates change; always re-pull at the time of entry. Section 201 safeguard and AD/CVD findings can apply depending on country of origin. Cross-reference for non-US destinations: EU TARIC · UK Global Tariff.

Disclaimer: No duty rate is asserted as fact on this page. Classification is the importer's responsibility under 19 CFR §141. Consult a licensed customs broker for binding rulings via CBP's e-Rulings programme (https://www.cbp.gov/).

10. Next steps

Request a quotation for this 700 kWp depot system

Deliverables are returned through the RFQ pipeline; no separate datasheet PDF is published on this page.

Numbers above are derived from the stated inputs against the formula in §3 and the cited documents in §5. Refresh the EIA Electric Power Monthly table, the AEO table, and the USITC HTS lookup before any procurement decision. No "No.1", review stars or third-party-verified-supplier claim is made on this page; the OEM product pages above are the source of make/model confirmation and datasheet revision. Reviewed by muse-ba.