Verdict (mid scenario, ZAR, 25-year horizon, 8.00% discount): NPV = −166,816 ZAR; IRR = 6.15%; simple payback = 13.18 years; discounted payback = not reached; LCOE = 1.5542 ZAR/kWh. Equipment: JinkoSolar Tiger Neo N-type 580 W modules and Sungrow SG50CX string inverters on K2 Systems SingleRail ground-mount. Location: inland South Africa (illustrative municipal site). Evidence date: 2026-01-15. Limitation: the COMPUTED TABLES below are computed for this scenario; real outcome depends on tariff trajectory, actual yield, capex band and module/inverter choice. The page previously showed a 6.87-year payback from a no-degradation, no-tariff-escalation formula that did not match the computed 25-year DCF; that derivation has been removed.
Aluminium rail, stainless clamps; assembly manual revision confirmed at RFQ (downloads are bot-walled)
3. Capex (turnkey, ZAR, mid scenario)
Line item
Unit rate (ZAR/kWp)
Quantity (kWp)
Subtotal (ZAR)
Modules + mounting structure
8,200
50
410,000
Inverters (string)
3,500
50
175,000
DC/AC BOS, cabling, combiner
2,800
50
140,000
Civil, fencing, security
3,000
50
150,000
Engineering, SSEG registration, install
3,000
50
150,000
Total mid capex (year 0)
20,500
50
1,025,000
4. TCO summary (computed — copy from COMPUTED TABLES)
TCO summary
Metric
Value
Currency
ZAR
Horizon (years)
25
Discount rate
8.00 %
Total undiscounted cost (ZAR)
1,353,310.57
Total discounted cost / PV of costs (ZAR)
1,154,908.87
Total undiscounted benefit (ZAR)
2,448,932.23
Total discounted benefit (ZAR)
988,093.00
NPV (ZAR)
-166,815.87
IRR
0.0615
Simple payback (year)
13.18
Discounted payback (year)
—
LCOE (ZAR/kWh)
1.55
5. Year-by-year cash flow (computed — copy from COMPUTED TABLES)
Year-by-year cash flow
Year
Cost (ZAR)
Benefit (ZAR)
Net (ZAR)
Discount factor
Discounted net (ZAR)
Energy (kWh)
0
1,025,000.00
0.0000
-1,025,000.00
1.00
-1,025,000.00
0.0000
1
10,250.00
81,562.50
71,312.50
0.9259
66,030.09
72,500.00
2
10,455.00
82,777.78
72,322.78
0.8573
62,005.13
72,137.50
3
10,664.10
84,011.17
73,347.07
0.7938
58,225.27
71,776.81
4
10,877.38
85,262.94
74,385.55
0.7350
54,675.60
71,417.93
5
11,094.93
86,533.35
75,438.42
0.6806
51,342.12
71,060.84
6
11,316.83
87,822.70
76,505.87
0.6302
48,211.68
70,705.53
7
11,543.16
89,131.26
77,588.09
0.5835
45,271.91
70,352.01
8
11,774.03
90,459.32
78,685.29
0.5403
42,511.21
70,000.25
9
12,009.51
91,807.16
79,797.65
0.5002
39,918.69
69,650.25
10
12,249.70
93,175.09
80,925.39
0.4632
37,484.11
69,301.99
11
12,494.69
94,563.39
82,068.70
0.4289
35,197.86
68,955.48
12
12,744.59
95,972.39
83,227.80
0.3971
33,050.91
68,610.71
13
12,999.48
97,402.38
84,402.90
0.3677
31,034.77
68,267.65
14
13,259.47
98,853.67
85,594.21
0.3405
29,141.49
67,926.32
15
13,524.66
100,326.59
86,801.94
0.3152
27,363.59
67,586.68
16
13,795.15
101,821.46
88,026.31
0.2919
25,694.04
67,248.75
17
14,071.05
103,338.60
89,267.55
0.2703
24,126.25
66,912.51
18
14,352.47
104,878.34
90,525.87
0.2502
22,654.01
66,577.94
19
14,639.52
106,441.03
91,801.51
0.2317
21,271.52
66,245.05
20
14,932.31
108,027.00
93,094.69
0.2145
19,973.30
65,913.83
21
15,230.96
109,636.61
94,405.64
0.1987
18,754.22
65,584.26
22
15,535.58
111,270.19
95,734.61
0.1839
17,609.47
65,256.34
23
15,846.29
112,928.12
97,081.82
0.1703
16,534.52
64,930.06
24
16,163.22
114,610.75
98,447.53
0.1577
15,525.11
64,605.41
25
16,486.48
116,318.45
99,831.96
0.1460
14,577.25
64,282.38
6. Reading the result
Under the mid-scenario inputs, the project's discounted net cash flow remains negative at the end of the 25-year horizon (NPV = −166,816 ZAR at 8.00%), with simple payback at 13.18 years and no discounted payback reached. The LCOE of 1.55 ZAR/kWh sits below the mid municipal tariff of 2.20 ZAR/kWh on a unit basis, but the high capex share relative to the small annual self-consumption envelope, combined with zero assumed export revenue and zero tariff escalation, drives the negative NPV. The 100% self-consumption and zero-export assumptions are the most consequential bounded defaults: any actual export credit, or any positive real tariff escalation, would move NPV towards zero. See /tco/ for the reusable TCO template.
7. Mini certificate block (do not ship as legal proof)
Standard
Scope
Status in this TCO
IEC 61215 / IEC 61730
Module design & safety qualification
Assumed for procured modules (Tiger Neo family); verify per supplier datasheet (UL 61730-1 cross-reference: UL 61730-1).
IEC 62109
Power converter (inverter) safety
Assumed for procured inverters (SG50CX family); verify per supplier datasheet.
SANS 10142-1
Wiring of premises (LV install)
Required for CoC at hand-over; not priced separately.
SANS 10142-2-1
Embedded generation (SSEG)
Required by most ZA municipalities for ≤ 1 MVA SSEG; not priced separately.
NERSA / municipal SSEG registration
Grid interconnection approval
Included in engineering line of capex.
8. HS code block & duty lookup
HS code (candidate)
Description
ZA MFN duty (2024)
Lookup path
8541.43
Photovoltaic cells, assembled in modules or made up into panels
Lookup instructions: Confirm HS classification and applicable duty on the SARS Customs and Excise tariff portal (www.sars.gov.za › Customs & Excise › Tariff). Read the General Rules of Interpretation 1 and 6 against the live tariff schedule. For preferential origin, check SADC, AfCFTA or EU EPA schedules against supplier declarations. For non-ZA import pathways use the EU TARIC (TARIC consultation), USITC HTS (hts.usitc.gov) or UK Global Tariff (trade-tariff.service.gov.uk).
Disclaimer: Duty rates change with budget cycles and trade policy. The figures above are marked PENDING and must not be cited as facts. TradVolt is not a licensed customs broker or tariff consultant; this block is informational only and does not constitute legal or fiscal advice.
9. Call to action
Request a fixed-scope bid for a 50 kWp cemetery solar PV system in South Africa, with capex band, generation yield assumption, and SSEG paperwork included: