After losing five hours a day of productive time during load shedding, I thought it was time to find a solution to my home office. This led to a wider investigation into power options in general.
THE SIMPLE, FAST SOLUTION: AROUND R10 000
The easiest solution is to purchase a “plug and play” inverter or UPS (uninterrupted power supply). For between R8 000 to R10 000 you can buy a 2.4 kilo-volt-ampere (kVA) unit that includes two batteries and an inverter that converts your DC battery power into AC power. That would produce 1.2 kilowatt hours (kW/h) of power and is sufficient to run a few lights, your computer and Wi-Fi. You connect it into a plug point to charge and when the power is down you can plug your appliances into the unit.
Just make sure you are buying a decent brand rather than the cheap knock-off. It is worth spending a bit more for reliability.
THE INVERTER HOUSEHOLD SOLUTION: R30 000 TO R50 000
If you want more than just keeping your computer going or, like me, have two offices at home, you may want to consider upgrading to an inverter system that feeds into your DC board. You would need an electrician to install it and you must get approval by the municipality. This is really a bigger version of the plug and play and the more batteries you buy the more you can power. According to the Western Cape’s switchandsave.co.za website, a system producing 2.4kW/h of energy would power 10 to 15 LED lights, a TV, fridge and laptop.
A system that produces 4.8kW/h of power is enough for an energy-efficient three-bedroom home. Basically, you could run the whole house except for heating appliances, such as your geyser, oven, microwave and electric hob.
The cost is determined by the number of batteries and the type of batteries. For example, we were quoted around R35 000 for a 5kW/h system with lead acid batteries and R55 000 if we opted for lithium batteries. Lithium batteries have double the lifespan so it is a longer-term saving.
CREATING YOUR OWN ELECTRICITY: R60 000 TO R200 000
The above options use Eskom to power up the batteries and do not save you any money. They would also not be sufficient for extended load shedding.
One option is to buy a generator and connect that into your grid. The upfront cost is not that high, we had a quote for R20 000, but the on-going costs are expensive. It consumes diesel at a rate of 2 litres an hour. If you have load shedding for five hours that will cost you R160 a day. The other problem is that you are allowed to store only 20 litres of diesel on your property so you will be going down to the petrol station fairly frequently. It would also be a challenge if we have diesel shortages.
The other option is to go solar. According to Jack Radmore of GreenCape, the average size for a household is between 4 to 7 kilowattpeak (kWp). This would have a capital cost of between R60 000 and R105 000 fully installed. This translates into an electricity cost (per unit or kW/h) of R1.30 for at least the next 15 years.
However, this figure does not include batteries. To use your solar power during load shedding it has to pull the power from a battery. If you are going solar you need to use the more expensive lithium batteries which will cost R50 000.
Radmore does not recommend going off the grid completely, “not only is this not the best-case scenario for South Africa as a whole, it is also very expensive. Battery costs are not yet at a point where it is financially feasible to go off grid.”
HOW TO MAKE THE DECISION
Mark Willoughby, managing director of One Energy, says you need to start by deciding what your goal is. In the short term it might be about keeping the lights on during load shedding but in the medium term it could be about reducing your electricity costs. Based on current electricity price increases we will be paying around R3 per kW/h within a few years. At that price, solar with batteries starts to make a lot of sense.
Willoughby says if you are looking at cutting electricity costs then the starting point is moving to a solar geyser. At around R24 000 it is the cheapest way to reduce your Eskom bill. Willoughby says you would cut about R600 to R800 a month off an electricity bill of R2 000 to R2 500 a month. If you consider that a R24 000 investment would effectively give you a saving of R7 200 to R9 600 a year – that is a 30% to 40% return on investment, tax-free.
The next step is to get your whole house energy efficient by using LED lights, a gas hob and upgrading to new, energy-efficient appliances.
When it comes to generating your own power, if you are on a budget you could start off with a “grid tied” system with solar panels and no battery. This will provide power during the day and you could change your usage to make sure your washing machine, dishwasher, pool pump and other appliances run during the middle of the day when the sun is generating the maximum power.
By using solar during the day, you could possibly also drop into the lower-tier rate for electricity tariffs.
While this will save you money, the downside is that you only have power during the day while the grid is running and you would not be protected from load shedding as the system is not permitted to run when the grid is down. Willoughby says this is not always clearly explained to a customer, “as soon as the grid goes down for any reason [load shedding, cable theft etc] the reference signal disappears and the “grid-tie” system automatically shuts down – as required by law.
“You can imagine how angry a consumer becomes the first time this happens with load shedding during the day and he expects the system will continue delivering power and it shuts down,” he says.
Which is why a hybrid system, although more expensive, is a better option. This can be achieved through either batteries or a generator. You could install a generator for periods of load shedding and, despite the high cost of diesel, as long as we don’t enter periods of prolonged outages, it could work well as a supplement to day-time solar power. A generator would be cheaper than batteries as an upfront cost but has ongoing costs, is noisy and a pollutant.
The “clean” solution is to purchase lithium batteries, which are more expensive than a generator, but which are charged “for free” by your solar panels during the day. Again, you can opt for how much battery back-up you require. You could create a less-expensive solar system that has just enough power to keep a portion of your circuit running like the lights and TV, for example, and spend around R60 000. If you wanted to power your whole home, apart from your oven, you could spend anywhere from R100 000 to R200 000, depending on the energy efficiency of your home.
Willoughby says for the full solar battery system to be cheaper than using Eskom the price of electricity would need to reach R3.50 per kW/h – which will probably be the case in about five years’ time. So, you could invest now for the convenience and then really benefit financially as electricity prices rise.
You can also follow a scalable option where you start with a few panels and build up or add batteries later. The key is to make sure you start with the correct inverter that can convert solar and battery power into your household grid. You just need to make sure you get good advice upfront.
“We often see a gap between expectations and reality which then comes as a big shock because the consumer thought he was buying a system to run his whole house when in fact all he receives is a small system to run a few lights for a couple of hours. This does enormous reputational damage to this industry,” says Willoughby.
The key is to find out how much power you really need and how much you can reduce your consumption through a few changes. Before you spend tens of thousands of rands on a solar system get your electricity usage monitored for a week so that you can get advice on what system would work best for you. Most quality suppliers will provide this as part of the service or deduct any fee off the cost of installation.
Make sure you get good advice and beware of fly-by-nights that will try take advantage of the current demand. Work only with reputable providers and rather pay more than try to do this on the cheap – this is a big investment.
SELLING INTO THE GRID
For certain municipalities, especially in the Western Cape, there is the option to feed back into the grid which the municipality uses to offset your electricity bill. Each municipality has its own rates – some higher than others. For example, the City of Cape Town charges a daily fixed fee of R12.36 to feed into the grid and pays you 70c/kW/h. Given the fixed daily fee you would need a really big installation to make any money selling to the municipality, so don’t count on this to pay back your solar installation.
ENERGY PER PANEL
Most panels produce 330W an hour. In South Africa you multiply that by five peak sun-hours.
HOW TO FUND YOUR SOLAR PANELS
If you need financing the best option is to use your home loan, however, according to Stanley Mabulu, channel management head at FNB Private Bank Lending, the bank will still follow the National Credit Act and apply affordability rules. They will consider if there is equity in the property to allow for a re-advance or further loan to finance the solar panel system. The savings are not normally considered as part of affordability, but you can use those savings to increase those home loan repayments to pay off your solar costs over a shorter period of time.
www.green-cape.co.za and www.switchandsave.co.za