NREL weird idea for long term energy storage
2022.04.11 – Ian Page https://cleantechnica.com/2022/04/10/nrel-researchers-plot-energy-storage-under-our-feet/ I'm not sure what I think of this one! The idea is to use fracked and uncapped wells. Pump natural gas into them under pressure and seal it up until it's needed. (Weird! Why not, not let the gas out of the well in the first place when fracking.) Then use the pressure to drive a turbine. Finally pump the natural gas back in again (don’t burn it) Eventually replace the natural gas with something else such as nitrogen, CO2, or hydrogen. (Nitrogen has the advantage that when it leaks it doesn't matter) There are some interesting features. When you compress gas, it gets hot. I guess that this heat is going to end up in the rock of the well and will cool off relatively slowly. This helps for when the gas is allowed to expand later as expansion takes heat and if there is some around in the rock to preheat it, the system will have a better round trip efficiency. The pro...