Balancing power demand with renewables is tricky. We need a way to store excess renewable energy and then use it later. Molten salt can be used to store excess energy as heat. But the people at DLR (German Space Center) Institute of Future Fuels think they have a better idea. Sulfur is cheaper and since the energy can be extracted chemically, you can control the temperature.
“Sulfur’s energy density is so much higher than that of molten salt, and also you get high-value heat,” DLR Institute of Future Fuels research head Christian Sattler said, per SolarPACES. “You have a very cheap storage medium in the sulfur, and since we propose chemical combustion, you can adjust the temperature to whatever temperature level you need.”
As SolarPACES explained, sulfur would be stored in a pile outside, and when heat is needed, it would be burned using solar energy.
https://www.thecooldown.com/green-tech/sulfur-solar-storage-thermal-energy/
Concentrated solar would be used to power the reaction.
“During this cycle, the sulfur is collected to form a pile, and the H2SO4 is stored in suitable tanks. When the sun is shining, the sulfur pile grows while the H2SO4 tank is emptied. During the night or when it is cloudy, the sulfur pile reduces [as some is burned, generating H2SO4] so the H2SO4 tank fills up.”
And then, because sulphur can be stored in a pile in ambient air, and is not affected by rain, sulphur is just as available as coal was, but with no CO2 emissions, and renewable, due to this thermochemical cycle.
It’s possible that this could become a closed loop system where the sulfur is continuously recovered and reused.
Each time you burn sulphur, it creates sulphur dioxide that can be processed to sulphuric acid, which can be reacted to create sulphur again. So this continuing cycle lends itself to a thermochemical process that endlessly cycles between sulphuric acid and sulphur.
https://www.solarpaces.org/why-solar-sulphur-cycle-ideal-seasonal-thermal-energy-storage/
Darcy Hitchcock 