Power and energy management company BBE Energy has constructed South Africa’s first locally developed linear Fresnel concentrated solar-power (CSP) demonstration plant, at its premises in Bryanston.
The demonstration plant comprises almost entirely of locally sourced components, is developed and constructed by local labour, and is estimated to come in at half the cost of importing a similar system.
BBE Energy director Steven Bluhm stated that the system was designed to be robust and applicable to local South African conditions, particularly the mining industry’s refrigeration and cooling requirements.
The company is now hoping to construct a full-scale demonstration project, and is looking to attract financiers and mining industry clients, which would also be interested in proving the technology in South African conditions.
The linear Fresnel device makes use of curved mirrors, which reflect and focus the sunlight towards a central pipe – a fluid-carrying, thermal, receiver-tube, which is then heated.
The water in the pipe is heated, at times reaching about 200 ºC, which produces high-pressure steam, which is then drawn through a valve.
The system is currently powering a small refrigerator, but can be used for various industrial processes and absorption refrigeration.
The mirrors rotate to follow the sun and the company is still experimenting with different drives to rotate the mirrors.
It is envisaged that the solar system could be used to power refrigeration and cooling systems in mines, which use absorption chillers driven by steam.
The system at BBE Energy comprises four mirrors, but should two more mirrors be added to the module, it could produce 75 kW. The system is modular and could be scaled up as required for different applications.
These six-mirror modules could be arranged in an array, and could produce some 3,5 MW from an area roughly equivalent to a rugby field.
BBE projects MD Richard Gundersen explained that the company started on a project to develop a solar energy system that could provide South African companies with a reliable energy producing alternative in 2008, “when it became clear that affordable and reliable power was going to become an increasingly problematic issue in the mining and minerals sector”.
“After completing a feasibility study for an installation in Namibia, we felt confident that we could design a local system that would be better suited to local conditions and more cost effective,” reiterated Gundersen.
BBE Energy previously sourced funding worth some R100-million, and completed the design and construction of numerous energy-efficiency and load-shift projects on behalf of Eskom.
