Mixed reaction to South African wind farm

Initial reaction to government's first experimental wind energy farm at Klipheuwel near Stellenbosch has been mixed, Eskom said on Monday.

"In local conditions it will have to be horses for courses with the correct turbine chosen for the weather conditions in that area," said Dr Louis van Heerden, Eskom's energy research manager.

This sentiment was borne out in the Klipheuwel research, which showed that of the three turbines, the smallest was performing the best under high wind (summer) conditions, while the largest turbine was performing the best under weak wind (winter) conditions.

Van Heerden said overall annual production for the three imported turbines, which rise like giant aircraft propellers on towers out of the flat farmlands, was just over four gigawatt hours (GWh) or one thousand megawatts.

An average house uses two to three kilowatts at peak times.

He said the three-year research programme has provided valuable information, including information about the turbines' operation and maintenance requirements.

Asked if wind power could be successfully used in the Western Cape, Van Heerden said it could indeed be harnessed from a "technical perspective", in that the equipment worked, but the technology was not economically viable.

"The dispatchability, predictability and generation cost of wind is a concern. Storage technologies, in specific battery type, are continuously monitored but the technology at this stage is non-commercial and not a viable option yet."

Van Heerden said wind power was still very expensive compared to conventional technologies in South Africa. The addition of bulk energy storage something might have an impact in future, if the energy could be stored and dispatched whenever necessary.

"This (bulk energy storage) has the potential to increase the plant capacity factor and provide dispatchable power. The critical issue is, however, to provide this energy storage on a cost competitive basis," said Van Heerden.

He said the cost of wind energy was decreasing constantly, but it would be some time before it was cheaper than conventional generating technologies.