Solar will get cheaper

DEAR SIR — We urge David Gleason to do more research on renewable energy before making such sweeping judgments (SA’s bottomless pit for renewables, Torque, April 10). Solar and wind energy, he states, are “horribly expensive” and don’t “do the job anyway” because they are “so dependent on natural conditions over which humans have no control”.

The intermittency of some renewable energy generators is well recognised, but does not diminish the fact that they deliver useful energy to the grid, with low or zero harmful emissions. Further, the costs of renewables are rapidly declining as opposed to those of fossil fuels.

If Mr Gleason digs a bit deeper, he will also discover Concentrated Solar Power (CSP), which can in fact act largely independently of natural conditions and deliver stable power to the national grid. CSP works in the same way as a coal or nuclear power station, except that it uses the free and infinite energy of the sun. CSP systems use mirrors or lenses to concentrate a large area of sunlight onto a small area, creating high temperatures. The heat is used to generate steam, which drives a turbine to generate electricity.

What sets CSP apart is its ability to store heat accumulated during the day and use this to generate electricity in cloudy periods or after sunset. This enables CSP to generate electricity in accordance with SA’s demand curve, and specifically during the early morning or evening peak periods. SA’s first three CSP power stations will have storage of between three and nine hours.

Yes, CSP is currently expensive when compared to coal, but costs are declining as the technology benefits from economies of scale through greater deployment internationally and intensive research and development. According to research in a recent study by the Industrial Development Corporation on the potential of CSP in SA, costs are likely to decline by 40%-28% by 2017 provided we deploy it at greater scale. This will justify local manufac- turing of components and create jobs.

Mr Gleason is welcome to call us at any time for an in-depth discussion on CSP and its value to SA.