Alpine Solar Wall Delivers Winter Power, but Swiss Regulation Stalls the Next Wave

Switzerland’s Muttsee dam hosts 4,872 solar modules on its south face, delivering a surprisingly strong winter share of annual output (43% of energy in the cold half) thanks to altitude and a steep tilt, but a five‑foot gap to the concrete is left so inspectors can map cracks—limiting the rear-face (bifacial) gain to about 1.5%. The project, funded by Axpo/IWB under the Solar Express regime, shows that site conditions and the regulatory framework largely determine alpine solar viability, with many such projects stalled or canceled despite measured performance that exceeds a valley reference plant.