ISO 50001:2011

ISO 50001:2011 specifies requirements for establishing, implementing,
maintaining and improving an energy management system,
whose purpose is to enable an organization to follow a systematic approach in achieving continual improvement of energy performance,
including energy efficiency, energy use and consumption.
ISO specifies requirements applicable to energy use and consumption,
including measurement, documentation and reporting, design and procurement practices for equipment,
systems, processes and personnel that contribute to energy performance.