Good to see the Linthal power plant has been brought online this month. It is a much larger and more complex project but it has the same principle as KPH.
https://interestingengineering.com/switzerlands-water-battery-operational
https://www.ge.com/news/reports/how-the-swiss-turned-an-alpine-peak-into-a-battery-the-size-of-a-nuclear-plant