Severn Trent Water – Improved unmeasured PCC monitor

Project Description

Severn Trent Water and Artesia have been working together to improve the robustness and accuracy of Severn Trent’s unmeasured household consumption monitor. The pre-existing individual household monitor was becoming less representative of the population in the company’s area. At the same time Severn Trent had invested in a small area monitor for measuring household night use. Severn Trent challenged Artesia to develop a method to adapt the small area monitor to calculate household consumption and integrate this with the existing individual household monitor.

Artesia developed a method to make use of small area fast logging to quantify household consumption in each area, and then use a weather demand model to estimate each area’s monthly measured household consumption. This was thencorrected for meter under-registration. The data analysis process from data collection, QA, statistical analysis, modelling, and extrapolation to WRZ and company level has been developed into an online application to allow Severn Trent to calculate their unmeasured PCC in-house on a regular basis. The application provides Severn Trent Water with the ability to compute unmeasured night use for different regions and time periods, with the reassurance that the method has been fully audited and conforms to best practice.

Severn Trent have now asked Artesia to develop a similar set of small area monitors in their Hafren Dyfrdwy area in Wales for assessing their night use and unmeasured household consumption and integrate these with their individual household monitor in this area.

The Severn Trent area consumption monitor has successfully been reporting unmeasured per capita consumption (PCC) for the past few years allowing Severn Trent to report a robust PCC value in its water balance. The completion of the Hafren Dyfrdwy area monitor will allow Severn Trent to report PCC for its whole area in line with regulatory requirements throughout AMP7.

As a result of this work, Ofwat gained insight into what future water demand might look like from the scenarios we developed, which demonstrated that significant reductions in water use compared to the current rate of consumption were feasible, with the right combination of technology, regulation and behaviour change. Some of the technologies considered are already proven but delivering such deep reductions will require collaboration between stakeholders, greater awareness of water scarcity issues in the UK, combined with greater leadership in moving this whole area forward.

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