This was a term we coined to follow on from prior use of the term ‘wind correlation penalty’.
In the case of solar, there is obviously an alignment of general harvest patterns because of the relatively narrow east-to-west spread of the NEM. The term is short-hand for describing how unit VWA Prices suffer across solar farms because of a high correlation of solar yield patterns.
A number of articles have been written on WattClarity to reference the ‘solar correlation penalty’, with some tagged that way (when we have remembered).