Normally, solar thermal power plants over 20 MW have been seen as the most cost-effective way of producing solar electricity, but large plants are not always practical to plan, design and construct.

“Small is beautiful – and most of all fast,” says Dr Werner J. Platzer, Department Head at Fraunhofer ISE.

“Systems ranging from 20 kW up to 2 MW can be more easily realised and they offer greater possibilities: the local heat or cooling demand can be combined with electricity production. This increases the profitability and facilitates the financing.”

Fraunhofer ISE has investigated the potential of small and medium-scale solar thermal power stations.

Plazer says: “For regional applications, the technology is economical where there is a large fraction of direct sunlight. This applies, for example, to the Mediterranean and the more southerly regions.

“For off-grid applications and for applications where the provision from the grid is unreliable, this technology is more cost-effective than employing a diesel generator.

“Air-condition could also be an important application. Over 40 million new air-conditioning units are sold worldwide annually and the tendency is increasing. Up to now, this potential application has not been used because market-ready products and demonstration projects that serve as role models are still needed.”