Interesting, we have had a micro-hydro (pelton wheel) @ 25metre head and 630 metre penstock length, in conjunction with solar, working here for years and it has paid for itself.
Our storage is not on a creek, just two reservoirs. The pumped side of ours is powered by water not electricity so the remaining water is let go to maintain environmental flows into a nearby creek. Rainfall and run off supplies our water.
As I've said here in the past , water is the most under utilised free resource on the planet. Its good to see at least some of you doing some thinking about it. As things get bad enough I guess it will slowly be worked out by the vegies in power.
I would be surprised at 80% round trip efficiency figures, especially if it includes evaporation, as stated in the article but who knows.
