Speaking as a engineer who generally applauds the competitive attempts but is sometimes freaked out by the technical challenges they put ahead of themselves...
Gravity Power: I hope they have a good idea for how they can make and seal a giant concrete piston and boreshaft. I think engineered pumped hydro has a major edge on these guys -- and energy cache.
Isentropic: potentially lower cost than us (gravel's not too expensive), but significantly more loss channels, so a tougher efficiency problem. Serious loss channel potential in the thermal gradient, plus both heat stores need to be pressurized in their main design.
Wouldn't trade places with them, but maybe they'd say the same.
We might eventually do a ~10kw version for homes or a ~100kw version for cars but that is very speculative / in the future.
I am modestly excited by Ambri, Aquion, and Tesla.
Gravity Power: I hope they have a good idea for how they can make and seal a giant concrete piston and boreshaft. I think engineered pumped hydro has a major edge on these guys -- and energy cache.
Isentropic: potentially lower cost than us (gravel's not too expensive), but significantly more loss channels, so a tougher efficiency problem. Serious loss channel potential in the thermal gradient, plus both heat stores need to be pressurized in their main design.
Wouldn't trade places with them, but maybe they'd say the same.
We might eventually do a ~10kw version for homes or a ~100kw version for cars but that is very speculative / in the future.
I am modestly excited by Ambri, Aquion, and Tesla.