ESOS: The Essentials – Go Green’s first evening networking event with Arup

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On 1st July Go Green held its first evening networking event, kindly hosted by Go Green members Arup. Everyone enjoyed the respite from the heat on the hottest day of the year when we settled into the auditorium with its air conditioning!

As evening temperatures peaked at 28 C outside, the obvious need for a tech fix to keep us cool was a pertinent reminder of how reliant we are on energy, which tied in well with the theme of the evening’s event: energy management.

Energy legislation has become a hot topic for businesses in the last few years since new regulations have come on line. Government seems to be steering business towards a more sustainable approach to energy use. However, there has been much debate about whether this is a burden and simply a tick box exercise, or whether is could be the perfect opportunity to get lasting value from investments in energy efficiency.

Liz Meddings, Senior Engineer from Arup gave us the low down on what has influenced English energy legislation and how this has resulted in the development of the Energy Saving Opportunity Scheme (ESOS), an energy assessment and energy saving scheme with a compliance deadline of 5th December 2015.

It was eye opening to see that almost 40% of the UK carbon emissions are from buildings.

Data from 2009 UK Government Carbon Plan - chart from Arup

The second largest contribution is from transport. Be aware that fuel auditing is included in the ESOS requirements. So even if you have a BREEAM Excellent building it is worth taking a close look at your staff mileage payments or fuel used for deliveries.

Liz explained that ESOS requirements usher in an important shift in energy legislation because the assessment has to be signed off by the Company Director which should ensure more top level support for investment. She then went on to highlight how Arup are themselves going about meeting the ESOS requirements. They are even using their Go Green Action Plan to help them with energy saving actions.

When thinking about energy use in your building you may find that so many little things need addressing that a full building refurbishment would be simpler, and Liz had tips on this too. Arup have a 1960s listed building in Edinburgh that they refurbished to achieve BREEAM Excellent and an EPC rating of A, which is pretty impressive considering it’s a retrofit not a new build. Here are some of the ways they achieved this:

  • Solar tubes increasing daylighting levels
  • Better U-values than building regs
  • Monitoring and metering
  • Lighting control – daylight dimming and presence detection
  • Natural ventilation and phase change materials in ceiling for thermal mass
  • Biomass boiler

Read Liz’s slides

Following Liz we moved onto the national energy picture. Paul Cosgrove from Arup took us back in time to discover how the national energy network came into being and then highlighted the current stresses that it is experiencing due to fundamental changes in the way energy is being produced and distributed. Whereas energy used to be all generated centrally in power stations, there is now a growing amount of microgeneration and energy from renewables being fed in everywhere, so the need for a smart approach is becoming all the more crucial. This then led onto Simon Roberts, Chief Executive for the Centre for Sustainable Energy laying out an aspirational vision for Bristol as a Smart Energy City.

Read Paul’s slides

Read Simon’s slides

The evening ended with networking over wine, beer and a buffet in the atrium. Thank you to all those that came along to make it such a fantastic event and to Arup for hosting us.


1. When measuring energy use, consider whether the amount used or the cost is a more appropriate metric for you.

2. Many energy savings measures can be zero cost such as altering thermostatic controls, and many others pay back in just a year or two such as using a automatic system to turn off PCs at night

3. If you have a portfolio of buildings, prioritise which buildings to start working on to reduce energy use – getting each building to reduce by a small amount might be easier than focusing on just a few big energy users

4. If in a large office, use a spreadsheet system to get staff to vote on how comfortable the temperature is for them in a rating out of five. Use this data to take an average and feed into the settings on a Building Management System (if you have one)

5. You can get a Fleet Healthcheck from the Energy Saving Trust to see where you can make reductions in fuel use


1. Do you employs 250 or more people? By ’employ’ this means anyone with a contract who is subject to income tax in the UK, even if they are on zero hours contracts or work abroad.


2. Do you have an annual turnover greater than £38.9 million & balance sheet greater than £33.4 million?

3. Are you part of a corporate group which includes others that meet either of these conditions?

This criteria are not exhaustive, see p.7 of the Environment Agency guidance for further details on qualifying criteria for ESOS

If you think that you meet any of these criteria then you should check the ESOS guidance carefully.

There is a fixed penalty of up to £50,000 for failure to undertake an energy audit (or for a false or misleading statement) and £500 for each working day until the breach is remedied!


  •  Get your audit signed off by an ESOS Lead Assessor
  •  Achieve ISO 50001 but bear in mind this can take up to 18 months, so if you haven’t already started it will only be relevant for phase 2 of ESOS
  •  Lodge a Display Energy Certificate for your building or Green Deal Assessment which is cheap and quick but does not provide a comprehensive financial analysis