Which measure would you inspect first if you had to advise the Financial Director?
Your choice is saved automatically on this device. You will revisit it on Reflect.
Purpose → Outcome → Evidence
Purpose of this stage: establish the commercial meaning of the supplier data before using the spreadsheet.
Outcome for this stage: After completing this stage, you should be able to interpret the case data and explain how self-consumption affects the economic value of solar generation.
You will demonstrate this by: distinguishing installed capacity, gross generation and useful generation; identifying the case assumptions; and explaining why a larger system is not automatically the better investment.
Evidence: your prediction response and concept-check explanation.
Story so far: You have accepted the brief. Before calculating, you need to understand what the supplier numbers mean.
The case · The proposals arrive
A larger PV system can generate more electricity, but Cape Manufacturing only saves money on solar electricity it can use when it is produced. This makes self-consumption the bridge between technical output and economic value.
If a system generates 100 kWh while the factory can use only 80 kWh, its self-consumption is 80%. In this simplified case, unused generation has no economic value.
| Proposal | A | B | C |
|---|---|---|---|
| Installed cost | R650,000 | R820,000 | R990,000 |
| System size | 60 kWp | 80 kWp | 100 kWp |
| Year-1 generation | 92,000 kWh | 121,000 kWh | 147,000 kWh |
| Self-consumption | 90% | 85% | 78% |
| Year-1 maintenance | R9,000 | R11,000 | R14,000 |
Excel instruction · read cells, do not calculate yet
A3:E9. Click B4: the Formula Bar should show 2.8, the tariff in R/kWh.A12:F17. System A is column B, B is C, C is D.D15 (147,000 kWh) and then D16 (78%). Note that the cell address changes in the Name Box.Useful habit: never retype an input elsewhere if a formula can reference the original cell. This improves auditability and reduces inconsistent assumptions.
Formative checkpoint · prediction before calculation
If you had only 30 seconds, which metric would you look at first: Installed Cost, Size, Gross Generation, Annual Saving, or Payback?
Write down your choice and one reason. You will revisit it at the end.
System C has the highest gross generation (147,000 kWh). System A has the highest self-consumption (90%). Those facts do not, by themselves, identify the best investment.
Excel + Google Sheets · same task
Excel Use the sheet tabs at the bottom. Click a cell and read its address in the Name Box; read/edit the formula in the Formula Bar.
Google Sheets Use the sheet tabs at the bottom. Click a cell and read its address in the Name box at the left of the formula bar; read/edit the formula in the formula bar.
For this page there is no platform-specific calculation. The cell references Case Data!B4, D15 and D16 mean the same thing in both.
Next: learn the few Excel moves needed to build the model confidently.