China is the runaway leader in supplying the world with the hardware to gather solar power. Now it's installing it at home at such a clip that the country's grid is getting more than it can use in some places.
While some approaches like compressed air might be less efficient, the simplicity might still make them worth it. Ultimately, what matters is being able to scale the tech quickly. If you can easily build a bunch of pumped water and compressed air facilities without needing any special minerals like you do for batteries, then the fact that they don’t store energy as efficiently might not really be an issue.
Indeed, China also has projects like this for pumped water energy storage https://www.rechargenews.com/energy-transition/chinas-1bn-bet-on-gravity-to-store-massive-amounts-of-green-energy/2-1-1550122?zephr_sso_ott=FuyYMk
While some approaches like compressed air might be less efficient, the simplicity might still make them worth it. Ultimately, what matters is being able to scale the tech quickly. If you can easily build a bunch of pumped water and compressed air facilities without needing any special minerals like you do for batteries, then the fact that they don’t store energy as efficiently might not really be an issue.