By Annabel Eaton

Many authorities on renewable energy advocate Concentrated Solar Power (CSP) as the ideal renewable technology for South Africa and see it as a vital and integral part of the energy mix in this country going forward.

Confronting a chronic energy shortage and the urgent need to decrease its dependence on coal-fired power stations, South Africa as a matter of urgency has to turn to alternative energy sources.  CSP is one of a variety of renewable technologies that is being introduced by Government as part of the country’s Integrated Resource Plan (IRP), which is expected to change the power generation paradigm forever.

Why then do CSP supporters believe so strongly in the benefits of this technology and, in particular, why is it suitable for South African conditions?

In the paper, ‘Value Proposition of CSP for South Africa’ (May 2012), Paul Gauché, Senior Researcher and Director for the solar thermal energy research group (STERG) at Stellenbosch University, proposes a value proposition for Concentrated Solar Power (CSP) in South Africa, and states: ‘CSP is the ideal future dispatchable power technology for South Africa.’

CSP overcomes intermittency

Experience in other countries has shown that a challenge faced by wind and pholtovoltaic (PV) technologies is their intermittency.

Gauché argues that CSP offers a solution to the intermittency of renewables, due to its storage capability.  “The storage capability of CSP essentially makes the technology a dispatch solution which means that CSP can provide peaking power and, in concert with other potentially cheaper renewables, it can also offer a sustainable baseload.”

Gauché says that this is especially true with hybridized CSP, where plants are permitted to include combustion of a fuel.

He explains that a local analysis of the Gemasolar CSP plant in Spain, a country which has similar Direct Normal Irradiance (DNI) values to that of South Africa, reveals that the plant is demonstrating 15 hours of storage using molten salts, and believes that such a technology in South Africa would easily provide similar capabilities.  

Supporting Gauché’s viewpoint is Dino Green, Mechanical Engineer and qualified, accredited expert in certification of energy performance, who outlines in more detail the concept of energy storage.  “CSP systems are capable of storing energy by use of Thermal Energy Storage (TES) technologies and using it at times of low or no sunlight to generate electric power.  This capability helps overcome intermittency problems, usually due to environmental fluctuations.

“Thus energy storage capabilities can improve dispatchability of solar power and flexibility in the network, as well as financial performance.”

Local resource and skills development

The paper, ‘Value Proposition of CSP for South Africa’, states that ‘CSP components, skills and operation risks are a good match for the resources, skills and infrastructure of South Africa.’

“This is because CSP plants are constructed out of steel, mirrors, electric motors, concrete and traditional power plant components,” Gauché explains.  “In South Africa, we are familiar with all of these and are also particularly skilled in the development and operation of equipment in harsh, dry conditions as demonstrated by the dry cooling experience here.”

CSP also has localization potential for South Africa, a tremendous advantage and one of the stipulations of the IRP.

“Distributed CSP could offer significant employment in the deployment and operation of plants, as well as Operations and Maintenance (O&M).  Once a large-scale rollout begins, an industry will be sustained for decades,” Gauché says.  “We also have a vision where small CSP plants can be an integral part of smaller rural communities in Southern Africa.”

He continues that South Africa could also develop some new technologies for local use, but also possibly offering international licensing opportunities.  

Backing Gauché’s belief in the localization potential of CSP is John Hazarkis, Head of Solar and Hydro at Siemens South Africa.  “The roll-out of CSP in South Africa and the rest of Afirca is not only good for ensuring a sustainable source of electricity, it also offers huge potential for job creation and localization,” he comments.

Hazarkis cautions however: “To create a sustainable industry more capacity needs to be allocated to CSP technology to ensure that the necessary investments can be made in local manufacturing and skills development.”

A complementary solution

Most authorities advocate the use of CSP in conjunction with other renewable energy technologies, especially wind and PV, and as a complementary solution to overcome intermittency issues.    

Green says: “Storage can help increase the mix of solar systems, CSP and PV, and wind energy systems.  It may be that CSP with TES may not necessarily be perceived as a competitor to PV systems,  but as a complementary enabler for large scale PV installations, and in the future they may work together to increase solar energy penetration in the power industry.”   

The STERG value proposition paper concludes that ‘an optimal mix of CSP with other renewables will be essential’.  Gauché explains that studies conducted show that CSP could provide all the electricity needs of South Africa, but at a price.  Because there are cheaper alternatives now and perhaps in the future, these technologies can be blended and in conjunction with each other still achieve the primary objective which is of course to provide South Africa with continuous power.  

To comment on this article write to Annabel Eaton

Or contact the editor, Jennifer Muirhead