SOCRATCES is a European Commission-funded Horizon 2020 project which is investigating the use of ‘calcium looping’ as a form of concentrated solar power (CSP) energy storage. It runs from January 2018 to September 2021. It involves the design of novel reactors, their construction and operation, and finally their integration into a full working prototype.
It takes a lot of energy to calcine limestone (i.e. calcium carbonate) into lime (calcium oxide) and carbon dioxide.
However, the other side to this chemical coin is that you get the same energy back if you recombine them. So, if you can calcine limestone when energy is plentiful, you should be able to recover much of that energy when it is scarce. This cyclical process is called calcium looping.
CSP uses banks of mirrors to focus large amounts of sunlight onto a small receiver, increasing its temperature to a level where steam can be produced to generate electricity.
In SOCRATCES, instead of producing steam we calcine limestone using specially designed CSP direct separation reactors (DSR’s) from Calix. DSR’s are ideal for this process because they already operate with indirect heating, something which is highly desirable for SOCRATCES.