We do use gyroscopic power storage, see e.g. https://h-cpc.cat.com/cmms/v2?f=subfamily&it=group&cid=402&lid=en&sc=US&gid=18492969&nc=1 https://h-cpc.cat.com/cm

We do use gyroscopic power storage, see e.g. https://h-cpc.cat.com/cmms/v2?f=subfamily&it=group&cid=402&lid=en&sc=US&gid=18492969&nc=1 https://h-cpc.cat.com/cmms/v2?f=subfamily&it=group&cid=402&l... https://www.activepower.com/ https://www.activepower.com/ ...and probably others. (A couple of decades ago I worked for a company that was a tenant at a datacenter that used these instead of batteries; it's not new or particularly exotic technology.)