The power station in Hällsjön is renowned for the development of alternating current transmissions. In 1893, the world's first commercial alternating current transmission was inaugurated between the power station in Hällsjön and the mining fields in Grängesberg. The original station was demolished and rebuilt in 1912. Some parts of the original building still remain. Today's power plant is fed with water from Vasselsjön through a 450-meter-long steel pipe and a drop height of 44 meters.