Should Storage be Included in EROI Considerations?
Article discusses the question whether storage should be part of EROI considerations and calculations. Take-away points:
1. A shift from an electrical system based mostly on energy stocks (with built-in energy storage function) to one based mostly on natural flows (with the construction of storage devices required to ensure large-scale availability) will probably be constrained by the energetic demands of the VRE-storage subsystem. Or in other words, high penetration of VRE will require the large-scale deployment of storage solutions, but there might be biophysical limits to how much storage can be deployed if the energy system is to remain viable.
2. Lithium-ion batteries, which are the fastest growing form of electrical storage today and are increasingly being touted as capable of supporting the energy transition to renewables, could probably only usefully contribute a short-term role to buffering VRE. The energetic productivity/EROI of an energy system reliant on lithium-ion batteries (and other similar electro-chemical storage devices) would indeed rapidly fall below the minimum useful EROI for society. The energetic requirements of pumped hydro storage, on the other hand, are sufficiently low to enable a greater displacement of conventional generation capacity and penetration of VRE, but wide scale deployment is dependent upon regional topography and water availability.
3. Storage technologies that would enable a full displacement of conventional generation capacity and 100% penetration of VRE at the current system reliability level are, as of today, unavailable. New storage solutions may emerge as a result of current and future research activities, but in order to assess their potential it will be necessary evaluate their energetic performances within the VRE-storage subsystem, all along the energy transition pathway. Only if these performances are markedly superior to existing technologies will storage potentially constitute the ‘holy grail’ of the energy transition that many expect.
VRE = Variable Renewable Energy.
EROI/EROEI = Energy Return On (Energy) Investment
[biophyseco.org] – Storage is the ‘Holy Grail’ of the Energy Transition – or is it?