Solar power proves its worth

2008-01-31 08:28

Cape Town - Solar water heating could save a household about 32% of the energy normally required to heat water, according to research conducted at the Nelson Mandela Metropolitan University in Port Elizabeth.

A postgraduate residence that had 10 solar water heaters installed saved 3 600kWh over three months - which was a worst case scenario - said director of the university's Centre for Energy Research, Professor Ernest van Dyk on Tuesday.

"The residences where the systems were installed are small houses and are suitable for... this experiment because they simulate an average urban house.

"In a normal household a similar system could save more than 50% compared to an electrical system."

Solar heating would also reduce carbon dioxide emissions. It was estimated that for every kWh of electricity generated by Eskom's coal-fired power plants, 0.97 kg of CO2 gas were produced.

"A typical solar water heating system can save a Port Elizabeth household between 150 and 200 kWh per month. That translates to approximately 150kg of CO2 emissions saved, which is huge if the number of potential users is considered," said van Dyk.

Electricity relatively cheap

Physics researcher at the university, Ronnie Mulder, said the South African public was slow to convert to renewable energy sources.

This was because electricity was relatively cheap, which affected the payback time for the initial capital outlay.

A typical system would consist of a solar collector panel, a small pump, normally powered by a photovoltaic panel, and plumbing into the existing household geyser.

The total cost could vary from R10 000 to R20 000. The expected payback time for the householder, with a subsidy scheme, was estimated to be between six to eight years.

In its plan on dealing with the country's electricity emergency, the government planned to install one million solar water heaters in households, commercial and industrial facilities over the next three years.

This was expected to save 650MW. It estimated that one solar heater would cost between R7 000 and R20 000.

- SAPA