El Hierro wind-hydro project (2014)
The Canary Island of El Hierro commissioned an 11.5 MW wind farm paired with a pumped-hydro storage plant, aiming to run its isolated grid entirely on renewables. Technical problems with the hydro system kept renewable share far below the 100% target in the project's early years.
The island kept relying on its diesel plant more than planned, and renewable penetration stayed well below the target for years.
El Hierro became a cautionary example of how hard it is to decarbonize an isolated grid without reliable, fast-responding storage.
The Red Sea project takes a different technical path, using grid-forming batteries instead of pumped hydro to create a stable isolated grid.
