The cave plant in Stazzona, in the municipality of Villa Tirano, is located at 394 meters, at the lower altimeter point of the entire hydropower system of Valtellina.  

HISTORY Work on the construction of the plant, begun in 1935, ended in 1938 with the operation of the plant. The plant has been revamped in the mid-1980s.  

OPERATION The plant uses the waters derived from the Sernio basin, made through the barrier of the Adda river by the same cross. Through a derating channel the waters are brought to the loading tank and then fed to the turbines in the engine room through a forced conduit. The waters released by the Stazzona plant are no longer used for A2A hydroelectric production in the province of Sondrio. At the Sernio basin, the central homonym uses the waters released in Adda for Minima Vitale, that is the amount of water released to ensure the conservation of the river ecosystem.