PV home systems explained

PV home

systems explained

By October 2022, over 81 days of loadshedding hours had occurred, more than in 2021 and 2020 combined. Many small office and house owners are faced with confusing options as to what to do about it. We asked a local installer of high quality home electricity backup and solar systems to offer some advice. Reinhart Schwendinger is the owner of SOVRN Energy (www.sovrn.co.za), based in Cape Town.

Reinhart Schwendinger Reinhart Schwendinger

It’s best to focus on the positive reasons for investing in Solar PV, through own production, storage and consumption. The driver shouldn't only be mitigating load shedding there being many more reasons to do so, eg. using ‘green energy’ and being more eco-friendly, safety and security are all good drivers.

Notably, solar PV & backup/storage energy is not for everyone. It is not easy to buy good value unless you are well informed.

Using the right team

I recommend that you find a great installation team, ensure they are registered PV Greencard (1) holders and work with qualified and motivated electricians.

Study their work, read their online reviews, even call past clients. Then commit to the project and please be patient; as demand has currently outstripped supply but it should not be at the expense of safety nor quality.

Options and investment costs

As an installer of Meister quality installations integrated in the electrical DB of the home or small office, my advice is slanted towards high end products, but for good reasons if you believe in investing in quality long-term energy security solutions. However since Eskom introduced Stage 6 loadshedding it soon become everyone’s problem. Below are options to help you tailor your personal solution to your budget.

1. Backup power only

The cost is around R10 000 to R20 000 for the small UPS covering 750 to 1800W. In my view for someone who only needs the basics covered like the WiFi router, laptop, TV, phone charger and a lamp, using a simple stand-alone 'box type' UPS for around R10 000 will work well enough.

This is a small box on trolley wheels that stays plugged in from which you run an extension leading to your equipment. It's cheap and works provided quality equipment is chosen. Note that deep cycle (gel) batteries used in these don't last much more than 1000 cycles from three to five years (depth of discharge dependent), and replacement cost is about R2 500 apiece.

You can spend even less (around R1500) if you only need to support your DC powered WiFi router and optical network terminal fibre devices, but do also buy some LED lamps (around R280/each).

2. UPS/Backup power only - no solar

For an investment of R50 000 to R100 000, UPS only (no solar) for supporting the medium load 3 000W to 5 000W, to cover more than just the basics, I recommend entry level pure sine wave inverters coupled with Lithium batteries. This is the preferred size for over 3 000 cycles and a better long-term investment than deep cycle batteries. They are integrated into the building's electrical distribution board (DB) in UPS mode and run all the basics as well as selected plugs and lights, even the refrigerator and freezer. This is a good option on a budget where a quality solution is required.

3. Approaching a solar PV system

For an investment of R100 000 to R180 000, UPS/backup/storage for a medium to large load 5 000W-8 000W requirement, a system that is 'solar enabled’ is recommended. This suits larger loads with room for expansion to include solar PV for daytime consumption and harvesting of solar power for self-storage. A fitout of solar PV on the roof could be added at a cost of approximately R80 000.

Premium inverters are used that offer easy addition of solar PV for your own production at a later stage (perfect phase 2 project when required). In the meantime, you have power when it's needed and later when and where possible, have the option to invest in your own production equipment without much hassle.

In summary, a well installed solar PV can be added to the above 'solar enabled' UPS/backup/storage system making a workable solution for a total investment cost of R180 000.

4. Full solar PV and backup/storage

For a more substantial investment, consider a R300 000 to R500 000 high-quality solar PV and backup/storage handling large 6 000W+ loads. The Meister solutions that we provide are built using German made inverters (e.g. SMA) and the best Lithium (e.g. BYD) battery tech available.

These solutions are for larger homes, or small businesses with fairly steady loads, where solar PV is used directly during the day to power devices and charge the batteries for overnight use. This is an amazing feature.

References

(1) The PV GreenCard Programme focuses on education, skills development, and training to build installer capacity as well as improve standards development and compliance in line with international best practice. www.pvgreencard.co.za