The question is still economics. At minimum the cost per watt/h need to be cheaper than to build a nuclear plant and have it run when demand exceed supply from

The question is still economics. At minimum the cost per watt/h need to be cheaper than to build a nuclear plant and have it run when demand exceed supply from renewables. Is this true for compressed air? When people discuss green hydro as a storage solution the numbers so far, from what I have managed to interpret, is around 3-5 times that off nuclear for the same amount of energy delivered. It is still technically possible to make a profit given enough subsidies and time, and it get much more economically if the hydrogen can be used directly in the production chain like steel and fertilizer. Right now there are a steel foundry in Sweden testing the technology and economics doing that, through I don't know how much subsidies and tax reductions were involved. Which all means the question about economics remains. There are many alternatives to fossil fuels but the primary question everyone debates is the issue of price. Without a price per watt/h or a time frame for when the investment get repaid its impossible to separate the practical from impractical, and the subsidy question is very relevant when discussing this on a national level.