ESOS – the proof of the audit is in the saving


Thomas Whiffen, Senior Energy Specialist, National Energy Foundation


Photo caption: Thom is a specialist in the sustainable built environment and combines a keen interest in energy use with a depth of knowledge from his process engineering background and years spent researching sustainable energy technologies for the non-domestic built environment. Thom has experience of industry and academic collaborations, publishing and presenting work in international journals, and at conferences.


If anyone needs convincing of the value of ESOS, we have the evidence. Over the course of the first tranche of ESOS compliance, we worked with a number of organisations and identified hundreds of energy-saving opportunities, the potential value of which was millions of pounds of savings.


Using half-hourly energy data, utility bills, finance records and mileage claims, we identified energy savings totalling 29 GWh per year, the equivalent of £12.5 million per year off fuel and utility bills. One particular situation we experienced among our site visits and examination of various plant rooms across the country was at a commercial site where they had an onsite combined heat and power plant. Although they were using the power, they were dumping the heat into the atmosphere, only to use lots of energy heating hot water for their industrial washing facility. On top of that, there was no space heating in their centre during winter. The solution was to re-engineer the systems to produce space heating during the winter and deliver low-carbon pre-heating for the industrial washing facility. Together, these two solutions are set to save £40,000 and 1.7 GWh per year.


Our experience and top 12 insights:

  1. There was positive engagement from the organisations we audited.
  2. The ESOS process improved energy-use record keeping.
  3. ESOS also improved energy awareness, and improving the visibility of their energy consumption helped organisations identify energy-saving opportunities.
  4. Major energy-saving opportunities were identified through behaviour change initiatives in both buildings and transport – in the case of the latter through reducing the number of miles driven and incentivising improved driving techniques.
  5. Major energy efficiency improvements were achieved through modernising the technology used to monitor and control energy, especially in areas of high energy demand.
  6. There was scope for energy management behaviour to be improved in all the buildings we audited.
  7. Likewise, there was room for all organisations to improve the support they provided to their staff through awareness and training initiatives.
  8. Lighting upgrades and boiler replacements reduced lighting and heating demand by 25-50%.
  9. Those organisations using fuel card systems were able to provide energy consumption data for their transport systems more easily, and the availability of driver fuel-use data made it easier to undertake behaviour-change programmes.
  10. The true benefit and power of ESOS compliance will be in the number and value of energy saving opportunities that are actually implemented.
  11. Over the next few months, we’ll be consulting with our clients, revisiting our original audits and working on strategies for implementing the savings we identified. We’ll also consider doing similar work for other ESOS-compliant organisations.
  12. The next stage will be to measure the savings and, finally, to prove the business case.


Looking ahead, the National Energy Foundation is leading on a new standard (ISO 17747: Determination of Energy Savings in Organizations) which is now at Final Draft International Standard stage. Once approved, it will provide us with a standardised and an internationally recognised method for measuring energy savings, and give us the ability for improved reporting to our clients.


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BDC 318 : Jul 2024