Which Type of Solar System Do You Need?
It’s important to decide what you would like to achieve by switching to solar, as different systems deliver different results.
Do you want power during load shedding?
Do you want to save on your electricity bill?
Do you want to live a more sustainable lifestyle?
Do you want to watch Netflix during load shedding?
Let’s take a look at the most common systems.
This means no connection to Eskom (the grid). With an off-grid system, load shedding is a thing of the past because you are not connected to the grid. This is the most expensive system because you need a large battery bank to run your appliances in the evenings and/or on cloudy days. You might also need a backup generator or large battery bank size to compensate for periods of bad weather.
The system will be designed according to your unique consumption profile, available solar panel space and budget. Getting off the grid is the dream, but it’s expensive. An off-grid system can cost from R180 000 to R300 000 for the average homeowner that uses about 30 kWh per day. The homeowner will also need to change energy consumption habits and become as energy efficient as possible. This might mean giving up luxuries such as underfloor heating and air conditioners.
The geyser and stove/oven will not be put on the off-grid system. The geyser will need to be replaced with a dedicated solar or gas geyser, the stove and oven with a gas appliance and lighting with LED alternatives. Once these big consumers are off the system, the system can be sized for the remaining appliances. This is the most cost-effective way to do things.
Your payback period on these systems range from 7 to 9 years. The panels will last 25 years, the inverter 10 to 15 years and the batteries 7 to 10 years if you go with a reputable lithium-ion brand. It’s also important to note that battery capacity decreases over the 10-year period. This means in year 10 batteries will probably have about 60% of the capacity they started out with. Currently, you can’t save money by going off the grid, but it does mean you won’t be reliant on Eskom for power and that you won’t have to deal with load shedding. As technology improves and the cost of components (especially the batteries) decreases, the payback period will reduce.
On-grid System (Also Called Grid-Tied Systems)
This means you are still connected to Eskom. For an on-grid system, you don’t need batteries. The power the panels generate is used immediately by appliances. This reduces your energy bill but doesn’t necessarily eliminate all energy costs. In countries where one can feed back into the grid, the excess power generated during the day can cover evening consumption, eliminating the electricity bill (or even result in being paid by the energy provider for feeding back into the grid).
Feeding back into the grid in South Africa requires permission from the municipality, but you won’t be compensated. So, you can only save money during the day. This option works best for offices where consumption occurs during the day. Consumption in most households occurs early morning and after sundown. The on-grid system would therefore not have a significant impact. On the roof of a commercial building, however, where most consumption happens during the day, you will see a significant reduction in the energy bill. The payback period is currently 3 to 5 years, depending on the project, which will reduce as the price of electricity goes up.
Approximate costs range between R30 000 and R100 000 for homes and farms, but will be more for large commercial projects. The big motivator to get on-grid solar is to save money and since costly batteries aren’t being used in these systems, the payback period is quick and you get a good return on investment.
Hybrid System (ESS – Energy Storage System)
This popular system combines the best parts of on-grid and off-grid systems. You are still connected to the grid, but with a smaller battery bank (compared to a total off-grid system) to get you through 4 to 8 hours of load shedding. When your batteries are fully charged, the excess power generated by your solar panels will be used by your appliances, saving you money during the day. The system can be set up to keep batteries at 100% to run your daily loads from the panels. It can also be set up, for example, that day loads run off the panels and a percentage of the batteries are used every evening, while the remaining percentage is kept for load shedding.
Your loads are split into two main sections: essentials and non-essentials. Essentials are connected to the battery bank. When the grid fails, all your essentials are still powered (lights and your chosen plug circuits). Your other circuits are wired as bulk loads. This means they only work when there is grid power available. If there is excess solar power (more than the essentials need in the day), it can be pushed into your most energy-consuming appliances to save money.
This is the most popular system for South Africans in the suburbs. The main goal is getting through load shedding, but you are also saving money during the day. The cost for an average home in South Africa ranges between R120 000 and R250 000. The motivators here include the luxury of not being affected by load shedding and saving some money during the day.
This system does not need solar panels. The batteries are charged by the grid when grid power is available. The inverter has a built-in AC charger that charges the battery bank from a wall outlet or your distribution board. Battery power is then used when the grid fails (load shedding).
You can select which appliances you want to run during load shedding and the installer will size the battery bank accordingly. When the power goes back on the battery bank will charge from the grid again.
This is the most cost-effective backup solution. You don’t save money with this solution, but load shedding becomes a thing of the past.
This system can also be the first step to a hybrid system. You can install the inverter with an AC charger and battery bank as a backup and when you want to upgrade to a hybrid solar system at a later stage you add a solar charger and solar panels. This gives you the flexibility of installing a solar system in two phases with load shedding issues addressed in phase 1.
Costs will run from about R15 000 to R100 000 for homes, depending on which appliances you want to use during load shedding. The main motivator here is convenience and to not be affected by load shedding. This is not a money-saving option.