Verdict (scenario model, evidence date 2026-01-15): For a 300 kWh / 150 kW LFP battery energy storage system at a South African distillery, over a 10-year horizon at an 8.00% real discount rate, the scenario TCO model returns NPV = −ZAR 7,932,473, simple payback = None, discounted payback = None, LCOS = ZAR 12.59/kWh. Do not procure on pure demand-charge economics at this use-case scale.
| Metric | Value |
|---|---|
| Equipment | 300 kWh / 150 kW LFP BESS (e.g. CATL LFP rack + Sungrow / Huawei PCS family) |
| Location | South Africa (Eskom Megaflex / municipal tariff mix) |
| Horizon / Discount rate | 10 years / 8.00% real |
| Evidence date | 2026-01-15 |
| Limitation | Screening-grade; sensitivity to usable-energy %, degradation/yr, and residual value assumed (see §3) |
| NPV (ZAR) | −7,932,473.00 |
| Discounted payback | None |
| Simple payback | None |
| LCOS (ZAR/kWh) | 12.59 |
South African distilleries face a composite cost stack: high Eskom Megaflex / Miniflex demand charges (R/kVA), scheduled load-shedding (historically reaching Stage 4–6, see Eskom load-shedding history), and rising municipal tariff escalation. A 300 kWh BESS paired with a 100–150 kW bidirectional inverter can shave peak demand, ride through utility outages, and — when paired with on-site biogas CHP — buffer generator output against mash-still load swings. The economic case rests on the spread between battery-levelled cost-per-kWh and the avoided grid tariff plus unserved-energy exposure.
| Sub-system | Real product / family | Public source |
|---|---|---|
| LFP battery rack | CATL LiFePO₄ rack system (e.g. CATL 372 kWh / 1C LFP cabinet, part of the EnerC product line) | CATL ESS product page |
| PCS / bidirectional inverter | Sungrow ST series — e.g. Sungrow ST250KTL+HV30 (250 kW, 1500 V DC, grid-forming capable) | Sungrow ST250KUXL datasheet (see also ST250KTL-HV datasheet PDF on Sungrow downloads) |
| Alternative PCS | Huawei Smart String ESS PCS — Huawei LUNA2000-200KTL-H1 (200 kW) | Huawei Smart PCS product documentation |
| EMS / controller | Sungrow iSolarCloud / Huawei SmartPVMS EMS | Sungrow iSolarCloud |
BESS system integration shall follow the OEM installation & operation manual (e.g. Sungrow ST250KTL-HV30 User Manual rev. as shipped with unit), including torque values at DC busbar terminals, SOC operating window (typ. 5–95% or 10–90% per OEM), and DC voltage limits. TradVolt does not republish OEM torque/SOC tables; request the manual revision matching the serial range at RFQ.
| Input | Assumed value | Bound / basis |
|---|---|---|
asset.ess.usable_pct | 90% | Bounded between 80% (conservative) and 100% (nameplate). 90% is a common LFP operating-window default; OEM warranty documents (e.g. CATL, Sungrow) typically allow 90–95% DoD. |
asset.ess.degradation_pct_per_year | 2.0% | Bounded between 1.0% (premium cells, climate-controlled) and 3.0% (high-cycling, high-temp). 2.0%/yr aligns with widely cited LFP calendar+cycle envelope for industrial C&I use. |
asset.ess.value_per_kwh_discharged | ZAR 0.00 / kWh discharged | No value assigned to kWh discharged; savings arise only from avoided demand charges, avoided unserved-energy, and end-of-life residual. Bounded −ZAR 0.50/kWh (degraded arbitrage) to +ZAR 0.50/kWh (favourable time-of-use). |
| Real discount rate | 8.00% | Bounded 6–12%; 8% real is a screening convention for ZA infra. Source: see citation row §10. |
| Horizon | 10 years | Bounded 8–15 years; 10y aligns with typical LFP calendar envelope (see §10). |
| Parameter | Value | Unit | Source / Note |
|---|---|---|---|
| Battery usable energy (DC, nameplate) | 300 | kWh | User-specified use-case capacity |
| Round-trip efficiency (DC) | 92 | % | LFP chemistry, typical PCS datasheet envelope (e.g. Sungrow ST250KTL-HV30 ≥ 98.5% max, system 90–92%) |
| Cycles per year | 330 | cycles/yr | 1 cycle/day operational schedule |
| Annual throughput (model year 1) | 89,100 | kWh/yr | Per scenario model; differs from 99,000 = 300×330 draft estimate because model applies usable_pct and degradation slope from Year 1 (89,100 = 99,000 × 0.90). |
| Discount rate (real) | 8.00 | % | Model assumption; see §10 citation row |
| Analysis horizon | 10 | years | Model assumption; LFP calendar envelope per §10 |
| Eskom demand charge (illustrative band) | ~350 | R/kVA/month | Eskom Megaflex tariff schedule PDF (see §10) |
| Avoided demand | 30 | kVA | Peak-shave envelope (model assumption) |
| Section 12B / 12V tax incentive | referenced only | — | See SARS §10; not modelled in NPV |
10-year lifecycle cost (PV, real terms):
TCO_PV = CAPEX + Σ OPEX_t / (1+r)^t − Residual/(1+r)^n + Decom/(1+r)^n
Net present value (TCO − PV(benefits)):
NPV = TCO_PV − Σ Benefit_t / (1+r)^t
LCOS:
LCOS = TCO_PV / Σ Energy_t / (1+r)^t
| Metric | Value |
|---|---|
| Currency | ZAR |
| Horizon (years) | 10 |
| Discount rate | 8.00 % |
| Total undiscounted cost (ZAR) | 7,305,149.56 |
| Total discounted cost / PV of costs (ZAR) | 6,970,805.25 |
| Total undiscounted benefit (ZAR) | -1,415,162.15 |
| Total discounted benefit (ZAR) | -961,667.75 |
| NPV (ZAR) | -7,932,473.00 |
| IRR | -0.5130 |
| Simple payback (year) | — |
| Discounted payback (year) | — |
| LCOS (ZAR/kWh) | 12.59 |
| Year | Cost (ZAR) | Benefit (ZAR) | Net (ZAR) | Discount factor | Discounted net (ZAR) | Energy (kWh) |
|---|---|---|---|---|---|---|
| 0 | 5,900,000.00 | 0.0000 | -5,900,000.00 | 1.00 | -5,900,000.00 | 0.0000 |
| 1 | 192,256.00 | -154,724.09 | -346,980.09 | 0.9259 | -321,277.86 | 89,100.00 |
| 2 | 196,101.12 | -151,629.61 | -347,730.73 | 0.8573 | -298,123.05 | 87,318.00 |
| 3 | 200,023.14 | -148,597.01 | -348,620.16 | 0.7938 | -276,745.92 | 85,571.64 |
| 4 | 204,023.61 | -145,625.07 | -349,648.68 | 0.7350 | -257,002.22 | 83,860.21 |
| 5 | 208,104.08 | -142,712.57 | -350,816.65 | 0.6806 | -238,759.92 | 82,183.00 |
| 6 | 212,266.16 | -139,858.32 | -352,124.48 | 0.6302 | -221,898.15 | 80,539.34 |
| 7 | 216,511.48 | -137,061.15 | -353,572.64 | 0.5835 | -206,306.24 | 78,928.56 |
| 8 | 220,841.71 | -134,319.93 | -355,161.64 | 0.5403 | -191,882.78 | 77,349.99 |
| 9 | 225,258.55 | -131,633.53 | -356,892.08 | 0.5002 | -178,534.89 | 75,802.99 |
| 10 | -470,236.28 | -129,000.86 | 341,235.42 | 0.4632 | 158,058.03 | 74,286.93 |
Year 10 cost is negative because residual value (ZAR ~700k base) less decommissioning (ZAR ~250k base) is treated as a credit to the cost line; benefits are negative because they represent avoided expenditure (cost savings to the distillery). The IRR is therefore negative and no payback is achieved within the horizon.
Re-running with the bounded defaults at their favourable ends (usable_pct = 100%, degradation = 1.0%/yr, residual value higher) does not move the NPV to positive territory at base CAPEX within the 10-year horizon; it shifts LCOS downwards but does not clear the demand-charge-only savings hurdle. The case becomes viable only if unserved-energy loss avoidance during load-shedding is monetised at > ZAR 30/kWh of shed kWh, which is a site-specific assumption not in the base model.
Producer responsibility / extended producer responsibility for end-of-life batteries: status to be confirmed at SARS / Department of Forestry, Fisheries and the Environment at procurement.
| Claim | Document |
|---|---|
| Eskom Megaflex R/kVA demand charge band | Eskom Megaflex Tariff Schedule (PDF) (live rate confirmed at RFQ against current Eskom tariff schedule) |
| LFP calendar life envelope | IEC 62619:2022 — industrial LFP safety/performance (cells commonly rated ≥ 6,000 cycles at 90% DoD; calendar envelope cited as model assumption) |
| O&M % of CAPEX (1.5–2.5%) | Model assumption (bounded), not a sourced figure; for engineering reference see NREL ATB 2021 — O&M cost assumptions for utility-scale storage |
| Residual value (ZAR 0.4–1.0 M) | Model assumption (bounded). Public second-life market reference: IEA Grid-Scale Storage report |
| 8% real discount rate (screening convention) | Model assumption (bounded). Methodology cross-ref: World Bank PPP Discount Rate methodology |
| Load-shedding Stage 4–6 (historical) | Eskom Integrated Report (historical stage references) |
| UN 38.3 transport test standard | UN Manual of Tests and Criteria, Rev. 7, §38.3 |
| IEC 62619 (industrial cells) | IEC Webstore — IEC 62619:2022 |
| UL 9540A (thermal runaway) | UL Standards — UL 9540A |
| NRS 097-2-1 (ZA grid code) | Eskom NRS Standards index — NRS 097-2-1 |
| SANS 10142-1 (LV wiring) | SABS SANS 10142-1 page |
| HS 8507.60 (Li-ion cells) | SARS Customs Tariff Browser — Chapter 85 (entry 8507.60) |
| HS 8504.40 (static converters / PCS) | SARS Customs Tariff Browser — Chapter 85 (entry 8504.40) |
| HS 8537.10 (control panels / BoP) | SARS Customs Tariff Browser — Chapter 85 (entry 8537.10) |
| Section 12B / 12V (tax depreciation reference) | SARS — Sections 12B and 12V (depreciation allowance) (referenced only; not modelled in NPV) |
| Component | HS code | Description | Duty lookup |
|---|---|---|---|
| Lithium-ion cells/modules | 8507.60 | Lithium-ion accumulators, including cells, modules, and complete ESS racks | SARS Tariff Browser — 8507.60 (confirm at procurement) |
| Power conversion system (PCS) | 8504.40 | Static converters, including bidirectional battery inverters | SARS Tariff Browser — 8504.40 |
| BoP — LV switchgear / cabinets | 8537.10 | Boards, panels, consoles for electric control | SARS Tariff Browser — 8537.10 |
| SCADA / EMS controller | 8537.10 | Industrial control assemblies | SARS Tariff Browser — 8537.10 |
Disclaimer on duties: Live MFN duty rates must be confirmed at the SARS Tariff Browser at the time of procurement. Preferential treatment under SACU / SADC / EFTA / AGOA may apply subject to certificate of origin and customs broker review. TradVolt does not assert any specific duty outcome.
This TCO is screening-grade, based on the scenario model output above and the bounded model assumptions in §3. Real project outcomes depend on the actual Eskom/Municipal tariff, Bi/Mini-flex structure, load-shedding schedule, BoP soil/civil conditions, and supplier commercial terms. The LCOS does not include inflation escalation, Section 12B/12V tax-depreciation benefits, or wheeling/discharge rule revisions; those are listed as positive optionality but not credited in the NPV above.
© TradVolt. Screening information only — not engineering advice. computed financial figures are computed; all bounded inputs are explicit model assumptions, not sourced facts.