Wind & solar energy pays off

Prof Paul Wessels has customised a wind and solar energy system to meet the needs of his home and farm, writes Annelie Coleman.
Issue date : 24 October 2008

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Wind-generated power is viable, sustainable, economical, and ecologically friendly,” enthuses Prof Paul Wessels, who runs his farm Krapfontein, 50km from Bloemfontein, on solar and wind energy. His passion is generating “clean,” sustainable alternative power using natural resources. “I had a gut feeling, long before the Eskom disaster, that South Africa was going to encounter serious energy problems, because we’re dependent on coal as a non-renewable feedstock source,” he explains. Prof Wessels is an academic and gynaecologist and has been farming with cattle and sheep since 1997.

“We settled on the farm in 2005,” he recalls. “At that time our power supply was a Lister generator and a system of 12V batteries, but that was inadequate for our increased power needs – remember, we now had to run a full household as well!” “We weren’t connected to the Eskom lines and wanted to keep it that way. The closest lines were about 6km away and even then the connection fees would have been exorbitant. also wanted to keep Krapfontein free from overhead Eskom cables, which disfigure the countryside. I’m not convinced their electromagnetic fields aren’t harmful. also wanted to keep our power supply as sustainable and ecofriendly as possible, without any harmful carbon legacies.

Starting with solar
The Wessels kicked off with a solar energy and battery system. “It seemed a sensible option for the Free State, where we have at least 200 days of sunshine per year,” Prof Wessels explains. “The biggest initial problem was calculating our energy needs and the specific energy requirements for the household appliances.

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No manufacturer could give me an indication of the energy required to run, for instance, a fridge or a dishwasher, so connected an amp counter to the appliances and literally counted amps – no mean feat, but it gave me a good indication of what our needs would be.” He installed 85W solar panels. initial 18 soon proved inadequate, but 24 and eventually 30 still didn’t meet Krapfontein’s needs. “The energy supply seemed adequate during sunny days, but it dwindled too much if we had even one overcast day. It became a gamble to ensure enough power to keep the farm and the household running in the rainy season,” Prof Wessels recalls.

‘The wind blows on overcast days’
The challenge was to find enough reserve capacity to provide power at night and on overcast days. “We needed another energy source that met our non-negotiable requirements of sustainability and environmental friendliness,” Prof Wessels says. “Under no circumstances would we consider anything harmful to the environment. �The wind in the Free State blows even on overcast days, so seriously started considering wind energy three years ago. It was relatively unknown in South Africa and had to literally start researching from scratch. “was told the wind supply in the Free State is inadequate.

Apparently Bloemfontein falls to the northeast of the imaginary line between Windhoek and Durban, which means less wind than on the other side of the line. My common sense told me otherwise and nevertheless carried on with my plans.” N elson Adams, a well-known alternative energy expert from Cape Town, helped the Wessels find the right equipment. They eventually settled on the largest domestic wind charger available locally, a 3,2kW Whisper from the US. he problem was where to put it for optimum exposure to the wind. Northwestern winds prevail in the Free State, Prof Wessels says, but strong southern winds occur regularly, so he measured wind speeds over a specific period.

The charger must be at least 15m above ground, but he put it at a height of 22m for optimum wind exposure. he combination of the wind charger and solar panels generates an average 550A per day, quite enough for Krapfontein. This is stored in 36V, 2 000Ah deep-cycle batteries connected to a 10kVA sine-wave inverter to ensure an output of 230VAC. This is then connected via the mainline to the farmhouse, garage and barn. “In the beginning, my biggest problem was not knowing how full the batteries were and what my electricity usage was at any given stage,” explains Prof Wessels.

“I consulted with Nelson Adams and bought a pentameter. Measurements are taken every morning before dawn, and show we never used less than 400A per day in the past three years. “We’ve proven the success of wind as an alternative energy source,” he continues. “We run the entire household and farm on it. Without a doubt it’s economical. Our power has been free after the initial investment of about R140 000, and we’re totally self-sufficient. “We have five freezers and two fridges constantly going and use compressors, centrifugal and submersible pumps, an electric lawnmower, a welding machine and other electrical equipment on the farm. We haven’t run out of power in three years.”

Unlimited potential for agriculture
“Don’t fall into the trap of trying to generate without measuring,” Prof Wessels warns those who want to explore alternative energy. “No decent motorcar runs without a functioning fuel gauge to show what’s being used and what’s still available in the tank. The same applies to alternative energy.” He’s adamant that nature holds enormous potential for power supply, for both agriculture and individual households. “It becomes a lifestyle to monitor your available energy,” he says. “It certainly makes you much more aware of what’s going in nature. Even my farmworkers are learning the art of efficient energy usage. “The sky’s the limit,” he concludes. “You can generate as much as you need by adding solar panels, wind turbines and batteries.” E-mail Prof Paul Wessels at [email protected]