I'm dubious about all long duration energy storage systems (LDES).
I feel their addressable market gets squashed between a) simply building more renewables and short term battery storage, both of which are reducing in cost due to massive buildout, b) making chemicals from renewable energy (i.e. green hydrogen, that then gets used as a building block for Ammonia or hydrocarbons).
As long as the former is able to cheaply eat marketshare then you can just use the fossil fuels it displaces in the hard to decarbonise markets and still come out ahead financially and in terms of carbon.
The latter can be used in jumbo jets or whatever, but also in fairly standard turbines for electricity production if needed, but emphasis on "if" because if you need it just as insurance against unpredictable demand/weather, then it's a plus point if you can just sell it to farmers, airlines or factories once you get to spring, and the physical storage already exists on a large scale for those purposes.
I think this already makes pumped hydro financially dubious, never mind more theoretical ideas.
The timeshifting of electrical heat demand for industry is another market nibbling away at this, and might be another use for the fluidized bed and sand storage part though.
I feel their addressable market gets squashed between a) simply building more renewables and short term battery storage, both of which are reducing in cost due to massive buildout, b) making chemicals from renewable energy (i.e. green hydrogen, that then gets used as a building block for Ammonia or hydrocarbons).
As long as the former is able to cheaply eat marketshare then you can just use the fossil fuels it displaces in the hard to decarbonise markets and still come out ahead financially and in terms of carbon.
The latter can be used in jumbo jets or whatever, but also in fairly standard turbines for electricity production if needed, but emphasis on "if" because if you need it just as insurance against unpredictable demand/weather, then it's a plus point if you can just sell it to farmers, airlines or factories once you get to spring, and the physical storage already exists on a large scale for those purposes.
I think this already makes pumped hydro financially dubious, never mind more theoretical ideas.
The timeshifting of electrical heat demand for industry is another market nibbling away at this, and might be another use for the fluidized bed and sand storage part though.