Overview | Kauai Island Utility Cooperative Like many islands, Kauai has been dependent on imported oil for electricity generation for decades. But an understanding of climate change and a desire to lower costs and volatility have pushed the island to embrace a heterogenous mix of clean energy solutions. Tesla recently completed a large PV/battery installation here of 13 MW PV with 52 MWh battery -- so far as I know, the largest to date. The co-op page is interesting reading. Of note, for the ~ 33,000 co-op customers: 10% of co-op customers have residential PV 7.5% of current needs is from old hydro, and the co-op is looking into building a pumped hydro from PV Utility PV is currently 37 MW Bio-mass is 7 MW On sunny days, PV has provided up to 90% of demand 62 MWh of online battery storage Added up (but not accounting for capacity), this works out to over 1.5 kW per customer from the utility I'm not sure why they do not use off-shore wind, but the integration of hydro and PV is smart since they tend to complement one another during the day. It will be interesting to follow the PV+pumped_hydro project, since it strikes me as a direct competitor with PV+battery.