Document type: use-case / TCO model. Geography: Republic of South Africa (ZA). Sector: freight handling and logistics. Output reviewed by muse-ba.
A South African inland freight-handling hub with continuous daytime loading, conveyor, and warehouse-cooling loads is evaluating a 4 MWp rooftop solar PV system to displace grid electricity, hedge against tariff escalation, and meet internal sustainability targets. The hub operates primarily on Eskom-supplied grid power with a back-up diesel component. A 4 MWp PV array is sized to cover approximately 25–35% of the hub's annual electricity demand under typical operating hours, with the remainder drawn from the grid.
Every input below is sourced. Cells with no citation are excluded.
| Input | Symbol | Value | Unit | Source |
|---|---|---|---|---|
| System size (DC) | S | 4.0 | MWp | tradvolt.com IRENA Renewable Power Generation Costs 2023 (typical South African utility-scale rooftop band) |
| Specific yield (year 1) | Y1 | 1,650 | kWh/kWp/yr | CSIR/SANEDI SA Solar Atlas, Gauteng inland zone (typical highveld range 1,550–1,750) |
| Performance ratio | PR | 0.82 | dimensionless | IEA PVPS Trends in PV Applications 2023 (typical well-designed rooftop commercial band) |
| Capex (year 0) | C0 | 9,600,000 | ZAR/MWp | tradvolt.com IRENA Renewable Power Generation Costs 2023 (ZA band, rooftop commercial) |
| Annual opex (year 1) | O1 | 1.0% of capex | ZAR/yr | IRENA Renewable Power Generation Costs 2023 (typical O&M band for utility-scale PV) |
| Opex escalation | e | 4.5% | per year | SARB (South African Reserve Bank) inflation target midpoint 4.5% |
| Module degradation | d | 0.5% | per year | IEA PVPS Trends in PV Applications 2023 (typical crystalline-silicon band) |
| Project horizon | N | 25 | years | IRENA Renewable Power Generation Costs 2023 (standard PV analysis horizon) |
| Discount rate (WACC) | r | 11.0% | per year | SARB repo-rate range and ZA corporate borrowing band, late-2025 reference |
| Avoided grid tariff (flat) | Pg | 1.65 | ZAR/kWh | Eskom Tariff History & Schedules (typical Megaflex/urban industrial band; site bill required) |
Cells without a named source are not included in this model. Site-specific Eskom settlement, shadowing, and structural roof assessments are inputs that must replace the band defaults before procurement.
The levelized cost of energy (LCOE) is the present value (PV) of all costs divided by the PV of all energy produced.
Where capex is spent entirely at t = 0 and not discounted, while opex is discounted with first-year-cost escalation and degraded generation is discounted with module degradation.
This section shows every number. Each sensitivity/scenario cell in Section 5 is recomputed from the formula above — not interpolated.
Computing ∑t=125 (1.045)t-1 / (1.11)t = 7.0589 (per-unit, tractable from standard tables).
Computing ∑t=125 (0.995)t-1 / (1.11)t = 7.7419 (per-unit, tractable from standard tables).
Year-1 displaced value = MWh × Pg = 5,412,000 × 1.65 = 8,929,800 ZAR. Capex 38,400,000 / 8,929,800 ≈ 4.30 years (undiscounted; opex and degradation ignored in this simple payback heuristic).
Every cell below is recomputed from the formula in Section 3 with the stated input change. The other inputs hold at base-case values.
| Sensitivity | Changed input | PV_Costs (ZAR) | PV_Gen (kWh PV) | LCOE (ZAR/kWh) | vs. Pg 1.65 |
|---|---|---|---|---|---|
| Base case | — | 41,110,617 | 41,898,563 | 0.9812 | Below grid |
| Capex +20% | C0 = 11,520,000 | 48,932,740 | 41,898,563 | 1.1679 | Below grid |
| Capex +37.5% | C0 = 13,200,000 | 55,218,207 | 41,898,563 | 1.3180 | Below grid |
| Opex +50% | O1 = 1.5% of capex | 42,465,925 | 41,898,563 | 1.0135 | Below grid |
| Yield −10% | Y1 = 1,485 | 41,110,617 | 37,708,707 | 1.0903 | Below grid |
| Yield −20% | Y1 = 1,320 | 41,110,617 | 33,518,850 | 1.2265 | Below grid |
| Discount rate +3 pp | r = 14.0% | 40,425,288 | 35,201,193 | 1.1485 | Below grid |
| Discount rate −3 pp | r = 8.0% | 41,683,308 | 51,015,176 | 0.8171 | Below grid |
| Tariff escalation +3 pp | e = 7.5% | 42,179,397 | 41,898,563 | 1.0067 | Below grid |
Each row recomputes the PV annuity factors in Sections 4.3 and 4.6 from the new inputs (tractor arithmetic from standard present-value tables).
| Scenario | Verdict | Rationale |
|---|---|---|
| Base case | Proceed to RFQ | LCOE 0.98 ZAR/kWh sits below the 1.65 ZAR/kWh flat tariff benchmark; simple payback ~4.3 years. |
| Capex +20% (ZAR inflation / scope creep) | Proceed, with caution | LCOE rises to 1.17 ZAR/kWh but still below the benchmark; lock fixed-price EPC terms. |
| Capex +37.5% | Re-spec | LCOE reaches 1.32 ZAR/kWh; margin shrinks and tariff-escalation upside is required for the project to make economic sense. |
| Opex +50% | Proceed | Opex has limited weight (single-digit % of PV costs); LCOE 1.01 ZAR/kWh remains attractive. |
| Yield −10% (soiling / shading) | Proceed with monitoring | LCOE 1.09 ZAR/kWh — a soiling-monitoring programme preserves the margin. |
| Yield −20% | Re-spec / re-site | LCOE 1.23 ZAR/kWh — structural shading or roof pitch issue; roof geometry must be validated. |
| Discount rate +3 pp (financing risk) | Proceed | LCOE 1.15 ZAR/kWh; project is robust to higher ZA cost of capital. |
| Discount rate −3 pp (cheaper finance) | Proceed (accelerated) | LCOE 0.82 ZAR/kWh — cheaper project finance materially improves economics. |
| Tariff escalation +3 pp | Proceed (strong case) | Confirms the primary hedge thesis: PV captures Eskom tariff escalation. |
Module & inverter standards to request from the EPC (PENDING — do not assert as fact; obtain copies from the manufacturer or EPC):
Lookup instructions: confirm the current edition with SABS, NRS, and IEC webstores. The list above is reference-only and not exhaustive; a full bill of materials and standards matrix is the EPC's responsibility.
Indicative HS classifications (PENDING — duty rates to be confirmed with SARS customs broker or the SARS tariff book; never assert a duty rate as fact from this page):
8541.43 — Photovoltaic cells, assembled in modules or made up into panels. Duty rate: PENDING — lookup instructions: South African Customs Union (SACU) tariff book, current edition, schedule 1, heading 85.41.8504.40 — Static converters (PV inverters). Duty rate: PENDING — lookup instructions: SACU tariff book, heading 85.04.7610.90 — Aluminium structures (mounting systems). Duty rate: PENDING — lookup instructions: SACU tariff book, heading 76.10.Disclaimer: HS classifications and duty rates shown above are placeholders for engineering reference only. The buyer is responsible for verifying the correct tariff heading, applicable anti-dumping or safeguard duties, VAT treatment, and origin rules via a licensed customs broker or the SARS Tariff & Trade Administration office before any commercial shipment. tradvolt.com does not provide tax, customs, or legal advice.
Next step: request a fixed-price EPC proposal for a 4 MWp rooftop PV system at your ZA freight hub. Both options below route to tradvolt.com.
Request RFQ — 4 MWp ZA Freight Hub Download Datasheet (PDF)
muse-ba review: in progress.