Most people are aware of the rebate available from ESKOM for demestic solar water heaters. Less well known is that ESKOM also have a rebate available for larger commercial systems. Firstly, their Non-Standard Rebate Offer for small, domestic systems that are already on the rebate program, put together in parrallel to form larger systems up to 7000 liters as per Fig 1. Their Standard Rebate Offer is for large, custom systems above 7000 liters. The rebate can pay up to 90% of the capital outlay over 3 years; this on top of the electricity savings which continue for years after the system is paid for. This program is particularly attractive for retrofitting existing commercial boilers.
Both programs require pre-authorisation from ESKOM but the generous rebate makes the process well worthwhile. The Standard Rebate Offer also requires M&V (monitoring and verification) after installation to assess the amount of the rebate. This is done through one of the universities. Ideal possible applications are office and commercial buildings with large central boilers, hotels, institutions and many other applications. The SABS approved Hills Solar evacuated tube collectors are ideal for these applications.
A summary of the program follows:
Non-Standard Rebate Offer
- 450 to 7000 liter systems
- Existing rebated systems installed in parallel.
- Only applies to ablutions, e.g. factory change rooms or sport club change rooms, not to process functions.
Standard Rebate Offer
- For large systems above 8000 liters.
- Scheme for developers and commercial installations where ESKOM purchases the actual energy savings in kWh
- Retrospective payments paid annually in arrears.
- Run over 3 years
- Pays 40% of modelled (projected) savings up front and then actual savings per annum for 3 years after 40% savings have been achieved.
- ESKOM will pay a maximum of 90% of project capital cost.
- Subject to initial modelling and then M&V (measurement and verification).
- M&V equipment must be paid for by developer/owner and ESKOM pay extra c/kWh.
- M&V done by agent appointed by ESKOM, usually a university.
- Only pays for hot water used, not generated so the modelling needs to be accurate in order to not over-specify.
- Only covers the energy saved by Solar Water Heaters, not by heat pumps.
- 2 kinds of projects
- Green field – New project with no history. Modelled and M&V after installation.
- Brown field –
- Old project, hot water energy usage needs to be measured first and then M&V after installation.
- System supplier should establish do own measurement of hot water usage in liters and kWh usage beforehand to enable modelling.
- Prior M&V to take about 2 months until client and ESKOM satisfied a baseline has been established.
- Prior M&V to measure existing hot water consumption and kWh usage of electrical water heating.
- Cost of M&V works out to about R35,000 to R40,000 for entire duration of the project. This paid by the client.
- Savings paid to the property owner at 70 cents per kWh.