1. Introduction: Over the last couple of years, load shedding has become a regular phenomenon in South Africa. Energy experts have warned that load shedding may continue for several years as Eskom battles coal shortages and high maintenance costs. Furthermore, ESKOM is seeking a 45% tariff increase spread over 3 years. With this in mind, a local businessman has decided to investigate switching to solar energy.

2. Scope: The local businessman owns an office block from 08h00 in the morning until 17h00 in the afternoon. The main equipment running on electricity are as follows:

The grass is cut once a week with an electric lawn mower. It takes about 2 hours to do this. There is an electric gate that is used during office hours to access the area behind the building.

The businessman is willing to cut back on aircons in time where there is constraints. There is an existing generator to keep the critical equipment running in case of loadshedding (no aircons used in this scenario).

The roof is flat and covers quite a large area. If need be, the shaded parking can also be used for solar panel space.

3. Request: The request is to come up with a proposal for the local businessman based on this information. The average electricity cost currently is R2,500 per month, but the consumption is expected to increase over the next couple of months (as per ESKOM tariff increases).

The following should be included/taken into account in the proposal:

Should the businessman opt to go completely off the grid or remain tied to the grid?

Should batteries be included? If indeed, how many?

The increase in the ESKOM tariff over the next couple of years.

Payback period.

Will this be profitable

Unit LED down lights LED strips Outside lights Aircons Aircons Aircons Telephones Laptops/PC's Sony TV KIC Fridge Microwave Zip Hydroboil Kyocera fax/copier Internet servers Geyser (150 L) Power rating (W) Number of units Only office hours 5 92 Yes Unknown 2 Yes Unknown 3 No 2,000 3 Yes 1,280 4 Yes 1,136 2 Yes Unknown 5 Yes Unknown 20 Yes Unknown 1 Yes Unknown 2 No 900 1 Yes Unknown 1 Yes Unknown 1 Yes Unknown No Unknown Yes 1 1 Unit LED down lights LED strips Outside lights Aircons Aircons Aircons Telephones Laptops/PC's Sony TV KIC Fridge Microwave Zip Hydroboil Kyocera fax/copier Internet servers Geyser (150 L) Power rating (W) Number of units Only office hours 5 92 Yes Unknown 2 Yes Unknown 3 No 2,000 3 Yes 1,280 4 Yes 1,136 2 Yes Unknown 5 Yes Unknown 20 Yes Unknown 1 Yes Unknown 2 No 900 1 Yes Unknown 1 Yes Unknown 1 Yes Unknown No Unknown Yes 1 1