As a retired engineer, I have dabbled with inverters and batteries for several years now, nothing very fancy, just a few trolley setups for load shedding.
I have done a lot of reading in several forums, and consider myself fairly well informed, but have no hands on experience with solar installations, just watching with awe as thousands of fellow South Africans spend big money to escape load shedding.
I have two areas that really do interest me though:
- The quality of the electrical installations (DB board etc) seem to leave a lot to be desired, I suspect many installations are not compliant, even though a COC was issued.
- Sectional title is very tricky, especially where shared roofs are involved.
I am currently a trustee in a small apartment block, which also has some commercial sections. There is a lot of roof space, but it is not going to be easy to cater for both commercial and residential needs, only the common property lighting and motorised gate would benefit from battery backup, and the ROI on investment would be difficult to justify large expense.
Most of the residents are at work during the day, very little power usage for residential during the day.
However I have been mulling over an idea, that I would like the experts to comment on.
Let’s suppose that agreement could be obtained for the body corporate to spend owners reserve funds on solar panels for the common property roof space.
It would need a proposal, a technical, and financial design, a budget etc, a special resolution, and may never get past this stage, but if it did, then my idea would be to allow owners to invest in their own batteries and inverters, according to their requirements, and tap into a shared DC busbar fed from the shared panels.
The solar power generated during the day, would be stored in owners batteries, for use by owners as they decide, during load shedding, or at night to save on electricity costs.
The commercial sections (medical suites) could use power during the day, for aircons and office use.
If there is more than enough solar power to go around, there would be no need for metering, but I have not thought this through in any detail yet.
The benefits of the above are:
- Economies of scale, and ease of management, having a shared solar array.
- No arguments over roof space, shading, maintenance etc, this would all be managed for owners by the body corporate
- Efficient use of excess solar power, if one user does not use his full allocation, another user can benefit.
- No more load shedding for those that buy in to the concept, at attractive prices.
- Owners will all pay for shared panels indirectly, but there would not be any special levies, just an option to spend on batteries and inverters, as needed.
- Savings on after hours usage of power, for lighting, and small appliances.
- Geyser heating, maybe, not sure of this at this stage, it would have to be carefully managed.
One thing I am sure of, is that the electrical DBs would have need an extensive redesign, which is not a bad thing.
I am thinking of using ATS devices (Automatic Transfer Switch) to automate load shedding switch over, still experimenting on this.
Is it possible to have a panel array that can be reconfigured at a central combiner box, on a patch panel basis, when it is needed to change panel setup, to meet changing user needs?
I would like to hear from the experts, your comments and advice would be welcome, even if my idea is not feasible, please tell me why!