The water energy nexus, an ISO50001 water case study and the need for a water value system

•Water as a resource needs to be managed.•The water–energy nexus, is detailed.•A water management case study using Energy Management Standard ISO50001 is given.•ISO14046 Water Footprint Standard and other benchmarking measures are discussed.•The requirement for a value system for water management is identified.

The world’s current utilisation of water, allied to the forecasted increase in our dependence on it, has led to the realisation that water as a resource needs to be managed. The scarcity and cost of water worldwide, along with water management practices within Europe, are highlighted in this paper. The heavy dependence of energy generation on water and the similar dependence of water treatment and distribution on energy, collectively termed the water–energy nexus, is detailed. A summary of the recently launched ISO14046 Water Footprint Standard along with other benchmarking measures is outlined and a case history of managing water using the Energy Management Standard ISO50001 is discussed in detail. From this, the requirement for a methodology for improvement of water management has been identified, involving a value system for water streams, which, once optimised will improve water management including efficiency and total utilisation.