How Chile’s electricity sector can go 100% renewable
If pumped hydro plants that use the sea as the lower reservoir can be put into large-scale operation Chile would be able to install at least 10 TWh of pumped hydro storage along its northern coast. With it Chile could convert enough intermittent solar into dispatchable form to replace all of its current fossil fuel generation, and at a levelized cost of electricity (provisionally estimated at around $80/MWh) that would be competitive with most other dispatchable generation sources. Northern Chile’s impressive pumped hydro potential is a result of the existence of natural depressions at elevations of 500m or more adjacent to the coast that can hold very large volumes of sea water and which form ready-made upper reservoirs.
Valhalla’s pumped hydro plant
My recent review of the Valhalla solar/pumped hydro storage project is what set me to wondering how much untapped pumped hydro potential there might be in Northern Chile, so I begin with a brief recap of pumped hydro potential there.
Valhalla’s project layout map shows its two upper pumped hydro reservoirs (they will be connected by a canal) occupying two natural depressions at around 600m elevation and about seven kilometers from the sea. According to Valhalla they can hold at least 25 million cubic meters of sea water and according to my estimates about 15 gigawatt-hours of stored energy:
Figure 1: Valhalla’s pumped hydro project layout
The question I had was how to go about identifying other prospective pumped hydro reservoir sites in the area, and the best tool at my disposal was Google Earth. So before beginning my search I checked to see whether I could duplicate Valhalla’s reservoir outlines and volumes from Google Earth, which in Northern Chile uses good-quality imagery and gives spot elevations to the nearest foot.
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