The hydro-electric power station at Blaenycwm was completed in 1904 by Moses Kellow, who had reopened Croesor Quarry (NPRN 40593) in 1895. Water came from a small lake, Llyn Cwm-y-foel, in a pipe supported on low stone pillars. The station provided 375Kw alternating current, used to light the mine, power compressors for air drills, and from 1905 to provide power for two early electric locomotives. The quarry closed in 1930, but was subsequently used for the storage of explosives.
In 1999 the power station was refurbished, a new pipe buried underground, and the station's Pelton turbine now feeds 500Kw into the National Grid.
W J Crompton, RCAHMW, 30 July 2009.