Estimating the EROI of whole systems for 100% renewable electricity supply capable of dealing with intermittency

Until the last few years it has not been possible to estimate the energy return on energy invested (EROI) for 100% renewable energy supply systems, because simulations indicating the amount of capacity required were not available. This study takes the finding of a recent simulation for 100%renewable Australian electricity supply, along with commonly quoted EROI values for the technologies involved, and derives a conclusion for total energy supply system EROI. The EROI values for individual renewable technologies do not provide a reliable guide to the system value because of the large amount of redundant plant that must be on hand to enable whole systems to meet demand reliably despite intermittency. The general finding is that 100% renewable supply systems probably have values that are too low to sustain energy intensive societies.