Celebrating the People's Republic of Christchurch

Something that I have been following for a while now is pumped hydro. The idea is to build high altitude storage lakes so that water can be pumped up to them when there is a surplus of generation capacity and electricity prices are low. Then when electricity is in short supply and prices rise the pumps can be reversed to generate electricity. Pumped hydro is considered the cheapest method for doing large-scale energy storage.