Service: Pump optimisation
Client: Northumbrian Water Group
Background
Energy efficiency of pumping assets is a key area of focus for water companies as they look to reduce their energy consumption and the impact of emissions on the environment.
Northumbrian Water Group (NWG) and Integrated Water Services Mechanical & Electrical (IWS M&E) hold a long-standing relationship. IWS M&E has earned its reputation with NWG through the successful delivery of energy efficiency analysis of assets.
When NWG decided to develop its energy efficiency strategy, IWS M&E was the natural partner of choice and were contracted to conduct a comprehensive programme of pump optimisation works.
Action
The programme of works undertaken by IWS M&E was based on a simple process of conducting surveys to identify energy saving opportunities before implementing and then verifying the original analysis.
Assets were selected for testing based on multi-departmental criteria with priority given to the largest energy users. IWS maintained a live calendar showing their availability for undertaking site surveys, enabling NWG to book individual surveys by selecting suitable dates from the calendar. A minimum notice of two weeks was given to allow for compilation and approval of job specific risk assessments and method statements.
IWS carried out all site activities in the presence of an NWG station operator and communication with the network controllers was maintained. This level of supervision provided assurance of minimal impact on the network during pump performance testing.
Two assets were typically tested per day and the team recorded a full suite of performance information during the site survey, which was later used for detailed energy consumption analysis. The team also benefitted from historical unit utilisation data, which was analysed in the first instance, to fully understand typical operation of individual pumpsets. This was followed by a key stage where performance data recorded at site was crossed with a typical operation of the tested unit.
From this analysis, IWS was able to provide a detailed report on the suitability and condition of the tested asset which determined the best solution – refurbishment of existing infrastructure, replacement for new highly efficient infrastructure or optimisation of the current site operational regime. Assets were selected for replacement or overhaul based on the energy payback period basis.
The cost analysis which was issued prior to an energy saving measure being implemented was scrutinised and verified. Any new or refurbished asset was tested once again to prove that the calculated energy saving was achieved.
A collaborative approach was key to the success of this project, with key stakeholders attending weekly catch-up meetings to conduct a frequent review of the works. Close co-operation with several specialist manufacturers was also crucial to the delivery of the works.
Case in point
A medium size split unit driven by a 315kW motor was assessed and found to be underperforming. Refurbishment was recommended due to an achievable payback period being just over 2.5 years by this overhaul. Following the refurbishment actual savings of £11.3k per annum were made. The energy savings achieved were close to the value predicted in the post-survey cost analysis. Additionally, a non-energy performance related mechanical problem was identified and rectified during the overhaul, increasing site resilience, and helping to avoid inevitable unplanned asset outage.
Result
This has been one of the most successful programmes undertaken by IWS M&E to date. Between March 2023 and September 2024, IWS M&E tested 77 pumping systems on behalf of NWG.
- Of 77 sites tested, 61 were classed as high energy consumers
- 46 optimisation opportunities were identified, where energy savings were achieved through altering the mode of pumping station operation
- Total savings of £358,887.31 or 417.22 tonnes of CO2 emissions per year
- Self-funded opportunities were identified, where the payback will take less than three years:
- Eight refurbishments providing total savings of £163,941.82 or 207.92 tonnes of CO2 emissions per year
- Four replacements providing total savings of £138,875.85 or 169.16 tonnes of CO2 emissions per year
- 30 combined opportunities providing total savings of £605,367.66 or 722.36 tonnes of CO2 emissions per year
Total cost saving: £1,267,072.64 per year
Total energy saving: 1,516.66 tonnes of CO2 per year
This project is something which can be replicated with other companies, driving decarbonisation of the water sector. This proof of concept validates that it’s not always necessary to replace assets – increasing carbon emission through the manufacturing process – and that a simple survey and analysis of the results can have a big impact in terms of cost and energy savings as well as reducing carbon emissions.
