Molten salt is “becoming the standard” for energy storage systems coupled with solar power in new markets, according to a study by the International Energy Agency (IEA).
The IEA’s ‘Renewables 2017’ market report, released on 4 October, said solar and wind together will represent more than 80% of global renewable capacity growth in the next five years.
In terms of storage, the study said: “Molten salt is quickly gaining favour due to its ability to reach higher temperatures. Likewise, using molten salt as a storage medium is becoming the standard among developers in new markets to increase storage hours and efficiency.”
However, the IEA warned renewables will become “more exposed to the risk of losing system value” unless investments are made for a “simultaneous increase in system flexibility”, including energy storage.
The study predicts that by 2022, “projects boasting 10 or more hours of storage— mostly towers utilising molten salt storage— are expected to become the new norm”.
This trend is being spearheaded by several projects including two in Chile, according to the study. The Cerro Dominador molten salt tower project, with 17.5 hours of storage is scheduled to come online in 2019, followed by the Copiapo molten salt tower project, with 13 hours of storage, expected to be operational in 2022.
The IEA said while a larger pipeline of projects is needed to “further standardise costs” across solar towers utilising molten salt, “some investment cost reductions are expected”.
In 2015, SolarReserve’s 110MW Crescent Dunes solar tower project in the US, with 10 hours of molten salt storage, cost around $9,000/kW, which the IEA said was “a higher cost due to the fact this plant was the first of its kind”.
However, the IEA said SolarReserve’s 100MW Redstone solar tower project in South Africa, which has 12 hours of storage, is expected to become operational in 2020 “with costs anticipated around $7,000/kW, due largely to a 30% decrease in the cost of heliostats”. Heliostats account for roughly 50% of the investment cost of solar towers, over previous projects, the agency said.
IEA executive director Dr Fatih Birol (pictured) said China is “now the undisputed leader in several renewables sectors”— and “effectively setting deployment volumes and prices” for solar PV and associated facilities worldwide. He said Chinese companies account for more than 60% of global PV manufacturing, “with its domestic market equal to half of global demand”.
Birol said the next key market for renewables and energy storage development is forecast to be India— which “will overtake the European Union for the first time”.
Earlier this year, South Australia signed a deal to build the 150MW Aurora Solar Energy Project in the state with eight hours of molten salt energy storage.
In September, Dubai’s state energy utility awarded a contract to build the 700-megawatt fourth phase of a solar power plant with molten salt energy storage.