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07 Aug 2015 00:00
Gerhard Minaar's farm is powered by solar panels on 5m high metal frames, pointing north. (Photo: Madelene Cronjé)
Gerhard Minnaar is a happy man. His game farm near the Limpopo border with Zimbabwe is at the far end of Eskom’s faltering electric grid — meaning the power supply in the area is erratic — but he does not rely on the power utility.
Instead, he runs most of his operation off solar panels. “It takes work. But making your own power is not that complicated,” he says.
His sprawling farmhouse is air-conditioned and even in summer his low-power air-conditioning is able to keep the house at around 25°C. The only noise is a faint hum coming out of a small room just off his large, tiled kitchen. Inside the room, rows of black battery boxes are stacked on a series of metal shelves. Each battery has a 20-year lifespan; together they can run his house off the grid for the whole night. During the day, they are charged by solar panels outside the house, which also power the house during the day. Pointed north on their 5m high green metal frames, the panels bring a wide smile to his face as he talks about them.
Everything in his his house and around the farm is energy efficient. His waterholes are supplied by solar-powered boreholes. But his pièce de résistance is an electric golf cart. A large solar panel on the cart’s roof — it also provides shade for the occupants — charges batteries under the bench-like seats. If he drives slowly, he can traverse his entire farm. At night the golf cart is parked in a custom-made shed where it can charge from the batteries inside his house.
The whole system cost Minnaar R400 000, and he expects to break even in five years through recouping the money he is not paying to Eskom. After that, he will be saving thousands of rands every month. Much of this saving he plans to invest back into his system, as technology inevitably improves. It also means he can appeal to guests who wish to stay in a more eco-friendly lodge.
Such is his trust in the system that he has asked Eskom to remove the thick, black cables that run alongside his farm’s dirt roads, a relic of an age when centralised power supply was the only way to go.
With Eskom buckling under the pressure of maintaining an aging fleet of coal-fired power stations fast approaching their decommissioning dates, (and facing a R200-billion budget shortfall), many, like Minnaar, are choosing to get off the grid.
Renewable prices for local consumers are rapidly dropping, thanks to massive investment in renewable energy at a producer level. Nearly R200-billion has been invested in over 6 000MW of renewable energy to date. This figure is also set to double, ensuring renewables add more power than Eskom’s giant Medupi and Kusile coal-fired power stations combined. The utility has also overseen the installation of over 100 000 solar water geysers in homes throughout the country (the programme has as its stated goal one million geysers).
All of these investments have seen the cost of solar photovoltaic panels drop from R5 per kilowatt-hour in 2010 to 90c per kilowatt-hour this year. In the same period, Eskom’s charge for electricity has almost tripled, from 50c per kilowatt-hour to R1.40 per kilowatt-hour. The utility has also been given permission to substantially increase this price.
The incentive for homeowners to get off the grid lies in security of supply and in saving money on electricity in the long term. South Africa’s renewable revolution is still being implemented at the mega-scale. The model that has driven renewables in people’s homes in other countries is yet to be implemented — mainly thanks to municipalities not allowing households to sell back to the national grid.
This model is at the core of the renewable energy explosion in countries such as Germany, where individual homes are given 20-year contracts to sell electricity back at guaranteed prices. On summer days German homes now supply half of the national grid. Small schemes are being tried in Cape Town, but municipalities still rely on the sale of electricity for a substantial portion of their income. — Hugh Pugh
How to take your home off the grid
Storage technology such as the new Tesla Powerwall with solar panels means that homes can now store enough electricity in the day to continue operating at night. But this technology is still expensive and struggles in the winter months, when the number of daylight hours shrinks to around 10.
South Africa does, however, have the advantage of having one of the highest levels of solar radiation in the world — so each panel can absorb more energy here than almost anywhere else globally.
Local energy companies have tended to advise that homeowners use a combination of Eskom and solar panels, in what is dubbed a “grid-tied” system. This will cost around R200 000 for solar panels and storage for a medium-sized family home. In new homes the system is now being tied in with mortgages, meaning an extra R2 000 a month on a 20-year bond.
Over that timespan, electricity generated by the panels will cost around 60c per kilowatt-hour with the mortgage; Eskom and municipalities currently charge homes upwards of R1.40 per kilowatt-hour.
Coupled with energy efficiency measures — such as LED lights and insulated or solar geysers — it means in less than five years those homeowners will have made back their investment and will be enjoying free electricity.
The biggest cost comes from buying solar photovoltaic panels. According to a Council for Scientific and Industrial Research guide to going off the grid, R90 000 will get you two-dozen solar panels and all the wiring. Batteries will cost a further R50 000, and they have to be replaced every decade or two. The cost of an inverter, installation and certification will bring the full cost to about R200 000. — Hugh Pugh
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