making the switch

MAKING THE

CLEAN ENERGY IS SWITCH A WIN FOR As the world grows more conscious about the negative impact of our lifestyles on the environment, ceaseless efforts have been made by academics and the civil ALL – FROM community to find ways to lower human degradation of the environment. Switching to renewable energy is the most preached solution. In South Africa, there are many households HOUSEHOLDS and big companies already using these renewable energy sources for their daily functions. Is it achievable for everyone?

Clean energy in the house

TO LARGE, Dr David Tinarwo from The University of Venda (Univen) has done extensive research over a couple of years about how rural, low-income communities could use renewable energy. SUCCESSFUL The biggest problem in Vhembe district, Limpopo, where his studies are based was excess usage of firewood for cooking and water heating. His studies lead to introduction of biogas COMPANIES. digesters to some low-income households in the district. We follow one of his studies that evaluates how viable digesters are in households. WE TAKE A A biogas digester uses organic waste to produce biogas, a methane-rich gas. It is a tank built into the ground with QUICK LOOK two sealed openings on the top. The openings lead to two underground chambers, one to store the waste fed to the digester and one for the biogas produced. AT SOME. Households can use biogas for cooking, space heating and water heating. For these functions, a household would need By: Mukosi Fulu a biogas that would be fed 5000 L of substrate (water and waste mixture) per day. Unfortunately, a single, average household cannot produce that much waste or obtain that much dung so a community digester is recommended. When it comes to installation, however, digesters are affordable. Acting general manager of Limpopo Economic Development, Environment and Tourism (Ledet), Lilly Maja, compares the affordability to building a toilet. There is obviously still a lot of research to be done to improve practicality of a biogas digester, but it promises to rid the villages of burning wood for fire through community digesters.

Make it your business

Keith Browne, the electronics engineer at the South African Astronomical Observatory (SAAO), tells us about the effectiveness of SALT's switch to solar energy.

What are the costs of switching to solar energy?

"That is difficult to say because costs are coming down all the time and seeing as the components are imported, it is highly dependent on the exchange rate. For a grid-tied solar system like ours, maintenance is minimal. The panels get cleaned every three months and tested for electrical integrity."

Considering the performance so far, is using solar energy viable, effective and practical?

"On viability – Any renewable installation should be considered prepaid electricity. You put down the capital based on an expected kWh that the system will produce. For us, the system will pay for itself in five years. That calculation was based on Eskom increases of 8% per annum. I do believe the last increase was more than that so we expect payback sooner. In the meantime, it helps to reduce the monthly running costs of the telescope.

On effectiveness – Yes, we pay less for electricity every month now. Our system doesn't cover the full load of the telescope, though – only about a third during the daytime operations. We are on a TOU tariff so the electricity used at peak times and during the day is more expensive than the electricity used at night. During the day, we have a large cooling load to condition the telescope for nighttime use and the solar installation offsets that energy.

On practicality – Being in the desert, between the winter rainfall and summer rainfall, regions having a cool climate and high altitude gives us a good solar resource so it's very practical."