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Climate Change blog - Cambridgeshire Schools Energy Efficiency Retrofit

Chris Parkin is the Community Energy Manager in Cambridgeshire County Council’s Climate Change & Energy Services Team. Following his presentation to ADEPT’s Energy and Clean Growth Group, Chris shares progress and learnings about the Council’s Schools Energy Efficiency Retrofit Programme.

We’ve been running the Schools Energy Efficiency Retrofit Programme since 2014, starting with traditional energy efficiency projects such as LED lighting, solar PV and improved heating controls. In 2019, the Council then declared a Climate Emergency. One of the actions adopted under our Climate Change and Environment Strategy was to work with schools to replace end of life boilers with low carbon heating systems, like Air Source Heat Pumps. These low carbon heating projects have become the focus of the programme.

Savings in energy consumption for schools

Historically, we've been achieving around 20% savings in energy consumption for schools. The traditional projects were funded by loans to the schools and designed to pay for themselves within 15 years through energy bill savings. But when you start looking at replacing the heating system with a low carbon heating source, things get more challenging financially.

Low carbon heating projects can deliver much greater energy savings, up to 77% in some cases. However, heat pump installations come with a very high capital cost and electricity costs a lot more than gas. Additional capital funding is needed so that the schools are not left with a net increase in their costs. The Council came up with a solution that monetises the social benefits of a project’s carbon savings to finance the projects – essentially, we put a financial value on the carbon savings using the Treasury's Green Book greenhouse gas analysis toolkit. We supplement this with Public Sector Decarbonisation Scheme grant funding, and our Education Capital team has made a contribution of the equivalent cost of putting in replacement boilers.

Finance - not the only challenge with low carbon heating projects

Finance isn’t the only challenge with low carbon heating projects. Noise from heat pumps can be a challenge if a school is very close to houses and space for the heat pumps can also be challenging in urban schools. Considering noise and location from the outset are important. Some heat pumps are quieter than others, but may necessitate other changes to the heating system. The efficiency of the building fabric can also been a challenge, particularly in some of our older schools. Fabric upgrades can have very long paybacks, we’ve seen 30-100 years – so our projects have to work with the existing building fabric. In some cases high temperature heat pumps have been installed, but where low temperature pumps have been specified, we’ve had to replace all the radiators which can only be done in school holidays.

We are currently installing air source heat pumps at 10 primary schools and have submitted grant applications for another 15. The heat pumps are already operational at one school, two others are just waiting for mechanical and electrical connections, work has just started at another four and contracts are about to be signed at a further three schools.

We also have one £3 million project to install Ground Source Heat Pumps of 720 kilowatts – two units of 360 kilowatts each – at a secondary school. These units will draw heat from 60 boreholes, 200 metres deep and supply 12 plant rooms around the school site. There is still some more commissioning work to do, but we are close to completion.

Five top learnings - Cambridgeshire Council’s Schools Energy Efficiency Retrofit Programme

I’ll leave you with our top five learnings:

  1. If you’re not measuring it, you can’t control it:
  • Put half hourly energy metering in place to understand heating use and performance of installed equipment
  • Review data regularly e.g. using an online energy monitoring platform, ideally with email alerts set up for unexpected energy consumption or generation patterns

2. Building Energy Management Systems (smart heating controls) can be complex for small schools/non-expert users to engage with, compounded by staff changes:

  • Front end software set-up should feature a ‘caretaker’ screen with just the basic settings that the school needs to routinely adjust
  • Ensure at least two staff are trained on the BEMS at handover
  • Video record the training and save this so the school can refer back to it
  • Keep a central record of each school’s system login details

3. Low carbon heating projects deliver much greater carbon reductions than solar PV, lighting etc works, but capital costs are high and (on a retrofit project) bill savings are unlikely to repay the initial capital investment:

  • Apply for grant funding where this is available e.g. the Public Sector Decarbonisation Scheme
  • Consider the monetised social value of the carbon savings in your business cases as well as cash benefits
  • Include electricity saving measures and/or fabric upgrades (where affordable) in scope to offset electricity demand from heat pumps and/or reduce thermal demand

4. Supply chain capacity and expertise can be challenging, especially for low carbon heating projects:

  • Ask potential suppliers for successfully delivered example projects
  • Speak to the customers for their experience
  • Include modelling of building thermal losses and assessment of electrical supply headroom in specifications for design work
  • Critically review proposed capacity and projected energy savings, seek third party expert review if you don’t have expertise in-house

5. Lead times for Distribution Network Operator quotes and electrical supply upgrade works are long (typically 3 months at each stage). Apply early!

Further information

  • For more information on ADEPT's climate change work, please take a look at the climate change hub.


Chris Parkin is Community Energy Manager in Cambridgeshire County Council’s Climate Change & Energy Services Team.

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