Look before you leap into a solar PV solution

Opinion by Teresa Settas, Marketing Director of the One Energy Group

Demand for solar PV solutions is far outstripping supply as South African homes and businesses look to escape the impact of Eskom’s debilitating load shedding on productivity, safety and security.

Before you rush into purchasing a back-up power solution, you need to take a considered and long-term view of how to get yourself as close to grid independence as possible, for the long term. Any money spent on an unsuitable and poor-quality back-up solution – both in terms of equipment and installation – detracts from your ultimate objective of greater grid-independence and self-sufficiency. Don’t be lured into the many cheap solutions that are flooding the market, punted by drop-and-go shippers and unqualified installers who offer no back-up or support, and even less in terms of warranties on their products.

If you want to take a step-by-step approach to greater grid independence, it is important to start with a scalable, quality solar PV hybrid solution that takes care of your immediate needs for back-up power during load shedding and power failures and allows you to scale up in future to self-generation by adding solar panels and additional battery storage if needed and as budget allows.

The big caveat here is that not all inverters and batteries offer this scalable functionality, so it’s essential to work with a renewable energy partner who is experienced and qualified in this field and understands and works with your medium and long-term objectives.

This is how you start your journey to greater grid-independence step-by-step

Step 1: Convert your electric geyser to a solar geyser

An electric geyser typically accounts for 30-40% of your monthly electricity usage and cost, so this is the most crucial starting point to reducing your daily electricity load, and which means you can also buy a smaller and more affordable PV solution. A 200-litre solar geyser, fully installed is around R27 000. On a R3000 electricity bill, you’ll save around R880 per month, amortising your outlay in just over two years, that’s without even taking annual electricity cost increases into account.

Step 2: Start with a hybrid inverter and li-ion battery as a back-up (UPS) solution that is expandable with panels and more batteries

Option 1: Back-up only, expandable

Install a 5kW Sunsynk inverter with one 3,6kWh li-ion battery set up as a UPS config initially – this means it will provide back-up for your essential loads – which we split at your DB board. Starting cost is around R84k including professional installation and all the required electrical protection and a COC. If you need a bigger inverter, then consider a Sunsynk 8kW Hybrid Inverter & 7.2kWh li-Ion battery, also expandable with solar panels and additional batteries, from around R128k.
Both these systems can be expanded with solar panels and additional batteries when needed and as budget allows.
Your essential load consists of the appliances and equipment that you want to be able to power up in an outage while non-essential is exactly that – items that are not necessary or vital during an outage.

Option 2: Back-Up and Self-generation

For this exercise, we worked on an electricity bill of R2000 per month, which is around 670kWh usage per month (22kWh per day) at a tariff of R3,50 per kWh (effective 1 July with the latest tariff increase). The system spec and cost looks like this:

5kW Sunsynk Inverter
7,2kWh li-Ion batteries
4,7kW solar panel array
Cost fully installed with all materials and COC: R160 000

This size system will take the household to around 90% off grid, supplying around 20kWh per day.

Payback and ROI: On an outright purchase:

Based on an 18,65% electricity tariff increase this year and 12,74% for the next year and then a very conservative 5%/pa thereafter after – this figure is in fact going to be higher as it does not factor in the increases that local councils will add on top of this – which means breakeven point is likely to be much sooner.
Your breakeven point is just over 6 years based on electricity savings.
Based on a very conservative escalation of 5% in electricity tariffs from year 3, your cumulative savings on electricity costs will be R350 000 after 10 years and R920 000 after 20 years – this is a savings multiple of 5,8 on your original investment of R160 000.

Payback and ROI: On a finance option:

Based on prime interest rate, with a finance term of 60 months with no annual escalation, your monthly repayment cost is going to be R3657/pm. (Figures may vary based on your credit rating and interest rates applied)
Your system will be fully paid off in five years and you will own it, and for the rest of the 20+ years of your system lifespan, you will be generating your electricity for free, with only a 10% reliance on grid electricity.
Based on a very conservative escalation of 5% in electricity tariffs from year 3, your cumulative savings on electricity costs will be R350 000 after 10 years and R920 000 after 20 years – this is a savings multiple of 4,2 on your original investment of R160 000.

The right size inverter, battery and panels is determined by doing an energy audit and monitoring for around 7 days to determine your real energy usage as well as peak loads (the most energy you draw at any one time). Don’t accept a quote or system design without doing the proper groundwork.

90% Off grid versus 100% off-grid?

It’s important to understand the system design and temper expectations with going fully off grid. A system that takes care of 80-90% of your electricity needs is the best option from a financial perspective – with a connection to the grid to recharge the batteries during cloudy/rainy weather.

The last 10% to get entirely off the grid can prove very costly. An entirely off-grid system would need to be sized at least three times larger than a grid-tied system that uses Eskom/council as a backup when there is extended inclement weather. While adding a generator can charge up batteries, this comes with the ongoing costs of fuel, system maintenance and emissions.

Track record and technical expertise matters!

Given the strategic importance of the decision you are making with regards to your electricity cost, supply and safety, as well as the quantum of your financial investment and expected ROI, work with a credible, qualified and accredited renewable energy partner that will be around for back-up, support and ongoing consultation over the lifespan of your system – that’s a good 20-25 years.

Far too many consumers are finding out that the result of going with cheap systems and questionable installers is poor system performance, outright failures of battery systems and a vicious cycle of constant ‘call backs’ and maintenance requirements – until the original installer simply does not come back to fix their shoddy work or goes belly-up, leaving you holding the can. In some of the worst cases, these fly-by-nights have disappeared with deposits, and the installations are an immediate fire and electrical risk to lives and properties.

The journey to greater grid independence is a big and important step and you need to be sure that the steps you take today are right for your needs down the line. The proper installation and management of a solar PV system is a complex undertaking that requires a deep understanding and experience of the various technologies on the market, that are suited to the specific circumstances of every client and site. Be prepared to wait for your installation as stock shortages for the short-term are real! The best solar installers are booked six weeks and more in advance.

Download our comprehensive checklist of all the considerations you should be looking at and the important questions to ask of any prospective solar installer.

One Energy is a multiple award-winning and market leading solar energy franchise established in 2011 with a national footprint. We have completed over 13 500+ perfect installations as at the end of 2022. Our ethos of perfect installations backed by quality work, service and products means that every one of our clients is a contactable reference.