If you can come up with an economically productive use of intermittent excess electric power, which beats Bitcoin in profitability, you can make a truly enormous amount of money selling whatever value you're generating to the people who want it.
Because it's a safe bet that excess intermittent electricity is going to be a growing resource over time.
You could almost certainly tune a pumped hydro installation to absorb the ramp of a reactor cycling up and down, but you'd lose the risk of running dry due to renewable unpredictability.
Hydrogen is a more interesting option. Not necessarily for energy storage, but as a fuel for use cases where electricity can't be used (like fertilizer or methanol rather than cars or heating).
Whereas pumped hydro can store far more energy (limited by upper reservoir size) then any battery array, but you pay for it in the fact that if you have a 1 MW turbine system on it, and 100 MWh of storage, you still only have 1 MW of power capacity (and about 100 hours of storage).
The problem is 100 hours of storage isn't much use if your grid needs more then that right now and it also can usually only be "charged" at about half that rate, so that 100 hours takes 200 hours to accumulate and that number is fixed - there's no surge capability - but if you're dealing with solar panels putting out on average 30% of their faceplate power, but obviously peaking at 100% frequently, you need to be able to store the peak to store it at all.
