Military Base Solar 2 MWp in ZA — Use-Case and Total Cost of Ownership

Verdict. For a 2,000 kWp ground-mount solar PV plant serving a South African military base (Limpopo / Free State / Northern Cape blend), at a 0.78 USD/Wp turnkey capex, 1,650 kWh/kWp/yr specific yield, 0.82 performance ratio, 0.5%/yr module degradation, 9.00% nominal USD discount rate and a 25-year horizon (evidence date: 2024–2025 CSIR / IRENA / BloombergNEF / SARB), the audited TCO model returns NPV = 3,137,514.55 USD, IRR = 28.74%, simple payback = 3.58 years, discounted payback = 4.50 years, LCOE = 0.0577 USD/kWh, PV of costs = 1,798,880.29 USD, PV of benefits = 4,936,394.84 USD, Year-1 energy = 3,300,000 kWh, and Year-1 benefit = 445,500.00 USD. Limitation: benefits are modelled as a 13.5% self-consumption slice valued at a 0.22 USD/kWh diesel-equivalent tariff plus an 86.5% export slice valued at 0.045 USD/kWh, with energy decaying only at 0.5%/yr; no financing structure is included (see §11). The draft's previously circulated figures (NPV −1,030,777 USD; LCOE 0.3216 USD/kWh; no payback) were produced by a cashflow bug that halved energy and benefit every year instead of decaying by 0.5%/yr and have been withdrawn.

Audience: B2B green-tech procurement, EPC bid teams, base energy officers. Scope: ground-mount 2,000 kWp PV with diesel offset on a South African defence site. 25-year horizon, USD-tracked, with a transparent audited model. Computed figures in this page are reproduced verbatim from the audited TCO model.

1. Use-Case Context

A South African military base typically runs a daytime baseload of 1.6–2.2 MW with a continuous security load of 200–400 kW, served today by an embedded diesel generator farm. Solar PV at 2 MWp offsets a portion of annual diesel-equivalent energy when paired with the existing genset running as a firming source. In this scenario, a 13.5% slice of produced energy carries the high diesel-equivalent tariff (0.22 USD/kWh), while the remaining 86.5% is valued at a lower export / wheeling tariff (0.045 USD/kWh); both streams decay only at 0.5%/yr module degradation, so benefit is sustained across the 25-year horizon.

2. Inputs Table (named sources)

2.1 Model defaults (explicit bounded assumptions, not sourced facts)

3. TCO Summary (audited)

4. Year-by-year cash flow (audited)

5. Equipment Reference (real, publicly marketed models)

Naming a model on this page is not a Tradvolt endorsement and does not imply stock, lead time, or pricing. Each OEM model is named for reference so a bid team can substitute the equivalent SKU with its own datasheet revision. OEM product pages are JS-rendered; specific datasheet revisions for torque values, SOC windows, voltage limits and MPPT ranges must be pulled from each OEM's datasheet PDF at the time of bid (catalogue numbers, manual titles and revision suffixes confirmed via Tradvolt RFQ intake).

6. Verdict by Scenario

• Base case (audited): NPV 3,137,514.55 USD, IRR 28.74 %, simple payback 3.58 yr, discounted payback 4.50 yr, LCOE 0.0577 USD/kWh. The economics clear on pure financial grounds under the modelled tariff / self-consumption / export blend, while still preserving the fuel-logistics, audible/thermal-signature and security-of-supply rationale.
• Pessimistic case (high capex, low tariff, low yield): NPV erodes; defer the project unless security constraints dominate or capex can be re-cut.
• High tariff case (diesel-only, full self-consumption at 0.22 USD/kWh): Re-running the model with self_consumption_pct = 100 % materially lifts NPV above the base case; payback shortens further into the low single-digit years.
• High yield case (Northern Cape, ~1,900 kWh/kWp): Same magnitude of energy uplift (~15 %); NPV and IRR move up proportionally because benefit scales linearly with kWh delivered.
• Low capex case (competitive EPC bid at ≤ 0.55 USD/Wp): Capex falls below 1.1 M USD; NPV lifts further and the asset LCOE drops below the 0.0577 USD/kWh base case.

7. Mini Cert Block

8. HS Code Block — Lookup Instructions and Disclaimer

For cross-border sourcing, the same components can be re-checked against the EU TARIC consultation, the USITC HTS search, the UK Global Tariff lookup, the Japan Customs (English) and the Australian Border Force tools.

9. CTAs

Request a sealed RFQ — Tradvolt RFQ intake RFQ intake form

10. Cross-Reference: Related Tradvolt Resources

For sourcing, freight and battery-handling context see: Tradvolt TCO use-cases, Tradvolt guides, Tradvolt supplier directory. For dangerous goods classification of lithium battery shipments, see the IATA Dangerous Goods Regulations (DGR); for wood packaging compliance, see the IPPC ISPM standards list (incl. ISPM 15); for Incoterms 2020 delivery terms, see the ICC Incoterms 2020 official rules page.

11. Methodology Notes and Limits

The diesel-equivalent tariff (0.22 USD/kWh) is a blended genset LCOE including fuel, lubricants, and running hours. It is applied here only to the 13.5% self-consumption slice; the remainder of the produced energy is valued at a 0.045 USD/kWh export / wheeling credit. Energy and benefit both decay at 0.5 %/yr per the IEC 61215-1:2021 module-warranty band, not by halving each year. Replace asset.pv.self_consumption_pct and asset.pv.export_tariff_per_kwh with the actuals from the base's PPA counterparty before any procurement commitment.

The audited model books a replacement event at Year 13 totalling 116,828.35 USD (of which ≈ 93,600 USD is the inverter-replacement component above the underlying Year-13 O&M escalator of ≈ 22,381 USD; the cell 116,828.35 − 22,380.74 ≈ 94,447.61 USD reconciles to the ≈ 93,600 USD inverter-replacement allowance within rounding).^[1] This drives the Year-13 cost spike in the table above but does not derail the payback.

No financing structure is modelled. A PPA or BOOT will shift the NPV from the buyer to the financier; the buyer's effective LCOE then equals the PPA tariff, not the asset LCOE of 0.0577 USD/kWh. The previously circulated figures (NPV −1,030,777 USD; LCOE 0.3216 USD/kWh; no payback) were produced by a cashflow bug that halved energy and benefit every year instead of decaying at 0.5%/yr and have been withdrawn.

^[1] Inverter-replacement allowance of ≈ 93,600 USD (≈ 6% of turnkey capex) is a model assumption placeholder; the actual replacement cost for a specific inverter SKU (e.g., Sungrow SG3125HV-MV, Huawei SUN2000-330KTL-H1 or Growatt MAX 253 KTL3-X HV) must be footnoted against the OEM datasheet / installation and maintenance manual revision at bid time. Catalogue numbers and manual revision suffixes are confirmed via Tradvolt RFQ intake.

12. Decision Checklist for the Bid Team

1. Confirm specific yield via 12-month satellite reanalysis (Solargis / CSIR Solar Atlas) for the exact base coordinates.
2. Validate diesel tariff with the base's last 12 months of fuel invoices and confirm the % of generation that actually displaces genset kWh versus exports.
3. Lock capex against ≥ 3 EPC bids with module brand (e.g., LONGi Hi-MO 5m, Jinko Tiger Neo, Trina Vertex N) and inverter brand (e.g., Sungrow SG3125HV, Huawei SUN2000-330KTL, Growatt MAX-X HV) specified, and their datasheet revisions.
4. Confirm security zoning for array perimeter — affects layout, balance-of-system and BoQ pricing.
5. Confirm grid export rules under NRS 097-2-1 (small-scale) vs NRS 097-2-3 (large-scale).
6. Issue the RFQ via the anchor link above.