Colbun plans up to 800-MW ocean-powered pumped-storage HPP in Chile

Chilean utility Colbun SA plans to tap into the Pacific Ocean to draw water into its proposed pumped-storage hydropower plant (HPP) with a capacity of up to 800 MW in northern Chile.

The company on Friday presented its plan for the Paposo pumped-storage hydro project, aiming to create a power station that will circulate desalinated water between its lower and upper reservoirs to store and release excess renewable energy that would otherwise be lost to curtailment.

Colbun said it had submitted the environmental impact study (EIS) for the Paposo project, which, if approved, would bring about an investment of close to USD 1.4 billion (EUR 1.29bn).

The plan is to take advantage of the natural coastal cliff in Taltal in the region of Antofagasta to build the reservoirs. The upper reservoir would be located on the top of the cliff at 1,500 metres (4,921 ft) above sea level, with the lower reservoir situated at the foot of the cliff next to the turbine hall and a substation.

Water that will flow between the reservoirs will be siphoned from the ocean, passing first through a desalination plant. To fill the reservoir, the water will be desalinated at a rate of 90 liters per second. During operation, this rate will be reduced to 30 liters per second to compensate for evaporation and internal consumption, Colbun said.

The project also includes the construction of a water catchment system, power lines, plant operation and administrative buildings, and a visitor centre.

The Paposo plant is expected to be able to generate around 1,800 GWh and contribute to mitigating renewable energy curtailment in Chile, Colbun said.

As for the timetable, the EIS for the project is currently going through a formal five-day admission procedure during which the environmental permitting authorities will decide whether to accept it for thorough evaluation. If all goes according to plan, Colbun expects to break ground in mid-2026 and commission the plant in the second half of 2029.

(USD 1.0 = EUR 0.922)

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