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Researchers in the UAE are developing an energy storage solution for concentrating solar plants that uses industrial waste.
The project at the Masdar Institute of Science and Technology is developing a thermal energy storage (TES) device from aluminium dross and steel slags. Researchers have been collecting waste from Emirates Global Aluminium and Emirates Steel with the aim of creating a useful, inexpensive device that can store thermal energy at very high temperatures.
Tests have shown the materials can store heat up to 1,000°C, some 400°C higher than the molten salts currently used for TES. The byproduct is less expensive than molten salts and the higher temperatures achievable will increase the operating temperature of CSP plant, increasing efficiency and reducing costs, said the researchers.
Kholoud Al Naimi, a researcher on the project at the Masdar Institute, said: “Currently, the only kind of material that can go to this high temperature is very expensive. So we’re very excited about having a free material that can get this hot and how it will impact efficiency and cost of CSP plants in the future.”
In a CSP plant, excess heat is diverted to a storage material so that when electricity is required after sunset, the stored heat can be released into the steam cycle and the solar plant can continue to generate electricity all night long. The storage also acts as a buffer to enable the “smooth” production of electricity.
The team is now working on shaping this material to develop a prototype. Dr Nicolas Calvet, assistant professor of mechanical and materials engineering, at the Masdar Institute, said: “During the production of aluminium and steel, their waste byproducts are obtained in molten form and can be easily poured into another container and cooled down without any additional treatment. We will modify this step and pour it into the mold of the heat exchanger we develop.
“We can use it up to 1000°C without any problem of degradation or cracks.”
“Developing efficient and inexpensive thermal energy storage devices is necessary if the UAE is going to see a greater uptake in solar energy. Right now there is a big focus on solar panels, but electricity generated by solar panels is still very expensive to store, especially at high power levels,” Al Naimi added.