We use gravity batteries in the UK. They work well and are pretty good at their efficiency. When you are creating massive systems they are made to last decades. There is always upkeep but it is the same with coal, gas and nuclear plants. All these renewables are far cheaper and far more cost effective than these power stations and for years the main problem has been that wind and solar cannot be used as base load, but with battery storage on a mass scale, thermal and hydrogen storage, we are now at a place where building out far more solar and wind than we need is viable and mixing in these technologies to provide base load and grid stability.