ALACAES, an Airlight Energy company, is currently constructing a compressed air energy storage solution that enables large-scale electricity storage. ALACAES’ storage solution will be a valuable solution for grid stabilization and energy balance of the electricity network.
This pilot plant in Pollegio, Switzerland, to test the feasibility of its electricity storage solution will exploit an abandoned tunnel in the Swiss alps as the air reservoir
The large-scale test contains a pressure chamber, isolated by means of two concrete plugs equipped with heavy doors for controlled access. In the framework of construction work of the two plugs in early 2015, Amberg Technologies (Switzerland) was contracted to furnish and install geotechnical and ambient instrumentation. Amberg has chosen Sisgeo International as a supplier of geotechnical monitoring systems.

For this project but also for monitoring of underground mining facilities Sisgeo developped a special convergence-extensometer, based on the displacement sensor technology. The system consists of a telescopic very rigid tube made of carbon-fibre reinforced plastic and thus it is very strong end light weighted. The thermal expansion of the system is practically neglectible. The system can be easily extended and adapted to the requested distance of measurement. Fixation points, normally groutable bolts include spherical joints to enable a simple installation.