Electricity is increasingly generated from renewable sources like solar and wind. Because these sources are not available around the clock, it is necessary to store electricity. Researchers from ETH and other institutions are exploring the storage of electricity by storing compressed air in caverns in the Swiss Alps.

The increasing reliance on intermittent renewable energy sources like solar and wind to generate electricity requires that electricity is stored to match demand. In Switzerland, pumped hydro storage could accomplish this task at least partially. Such plants store electricity in the potential energy of water that is pumped to a higher elevation.

Whether additional pumped hydro plants will be built in Switzerland is uncertain because of questions about their profitability and resistance from environmental organisations. Storing electricity in the form of compressed air in caverns is an alternative. Researchers from ETH and other institutions are collaborating with the company ALACAES to investigate the potential of compressed air storage in the Swiss Alps.

With support from the Swiss Federal Office of Energy, the Swiss National Science Foundation, and the Commission for Technology and Innovation, the researchers carried out experiments with the world’s first pilot plant for compressed air storage near Biasca. The pilot plant, built in a decommissioned tunnel used for the excavation of the Gotthard base tunnel, used thermal storage units based on rocks excavated from a river bed and a metallic phase-change material. The technical feasibility was demonstrated with plant efficiencies of about 67-78%.

One the steel doors and concrete plugs that contain the compressed air in the cavern.

Further information about the project can be found on the project website. Note in particular that there are videos produced by SNF at:

video (German)

video (German with english subtitles)

The researchers involved in this project are ESC member, and head of the Professorship of Renewable Energy Carriers (PREC)Prof. Aldo Steinfeld, Dr. Andreas Haselbacher, and Phd student, Viola Becattini.

The Professorship of Renewable Energy Carriers performs pioneering R&D projects in emerging fields of renewable energy engineering, operates state-of-the-art experimental laboratories, offers advanced courses in fundamental/applied thermal sciences, and produces qualified scientists and engineers with expertise in renewable energy technologies.