This sector comprises establishments engaged in the provision of the following utility services: electric power, steam supply and water supply. Within this sector, the specific activities associated with the utility services provided vary by utility: electric power includes generation, transmission and distribution; steam supply includes provision and/or distribution; and water supply includes treatment and distribution. Establishments in this sector typically provide power, steam and water through a permanent infrastructure of lines, mains and pipes. They are grouped together based on the utility service provided and the particular system or facilities required to perform the service. Also listed under this major sector are companies that operate as independent producers and/or distributors of power.