Molten silicon as the basis of a new generation of CSP systems


A module that contains 1,000 litres of molten silicon at 1,410°C, directly placed in the centre of a solar concentrator that can store just over 1 MWh of energy (10 times more than molten salts) and directly produce electricity via solid state converters, with no moving parts or heat transfer fluids. Such systems are being developed at the Universidad Politécnica de Madrid’s Solar Energy Institute with the aim of creating a new generation of low cost CSP systems. The key to this technology stems from the use of thermophotovoltaic converters instead of turbines, to produce electricity directly from the incandescent thermal radiation of molten silicon. The result is a device that is compact, modular, easy to install, silent and robust that can be used in both large power generation plants and in smaller-sized systems for the cogeneration of heat and electricity in urban centres.

Today’s CSP technology is largely based on the same concepts that have been used in power plants since the start of the 20th Century: generated heat, in this case via solar power, which produces pressure differences in a fluid that makes it move, transferring its mechanical energy to a turbine and transforming that energy into electricity. The use of an established electricity generation technology with a high level of development was probably the reason why it has been possible to execute large-scale CSP power projects over such a short period. However, conventional power generation technologies may not be the best solutions to develop the CSP plants of the future, in which scalability, modularity and reliability are considered as being key criteria.


In this regard, CSP power offers two fundamental aspects that distinguish it from other thermal power generation plants and that should be considered when planning new systems. First is the haphazard nature of the solar resource, followed by the need to incorporate a thermal energy storage system, a key differentiating aspect that allows it to compete with other renewable generation technologies. Both aspects combine the need to offer extremely compact storage and generation technologies that facilitate the modularity and scalability of the system, allowing easy installation in any site, and particularly, in regions close to the final consumer. Read more…

Alejandro Datas Medina
Research Scientist, Solar Energy Institute of UPM

Article published in: FuturENERGY October 2016