Working towards zero-carbon heating emissions

The Committee on Climate Change's recent report on reaching net zero carbon emissions included some interesting proposals for decarbonising the UK's heating systems, as Paul Reeve explains

At the beginning of May, the UK government's independent Committee on Climate Change (CCC) issued a recommendation that the country should move rapidly towards a 'zero net carbon' economy. While the UK is already committed to a hugely challenging 80% greenhouse gas reduction target by 2050, the CCC's latest report, Net Zero: The UK's contribution to stopping global warming, points the way to zero UK carbon emissions over the same timescale and prompts the government to take early action.

While the new report spans the entire UK economy, a specific chapter on buildings focuses on the fundamental challenge of achieving 'low to no carbon' building heating. The CCC refers to the essential and growing role of electricity from renewables, and the need to deploy smart tech to control the country's energy demand, supply and storage. The stand-out recommendation is for the massive roll-out of hybrid (dual fuel) heat pumps and hydrogen boilers across the UK, either supplementing or replacing natural gas boilers. This would boost low-carbon heating in UK buildings from 4.5% now to a game-changing 90% by 2050 – but at an eye-watering abatement cost of around £140 per tonne of carbon dioxide equivalent (tCO2e). This would involve tens of billions of pounds of capital expenditure per year.

Although the CCC adds that installing these technologies would become more affordable if they were deployed at scale, it freely acknowledges this won't be easy. First, it would require positive, urgent and joined-up government energy policy, to include “a fully-fledged strategy for decarbonised heat“ by next year, along with a 'Future Homes' standard aimed at ensuring UK new builds have low-carbon heating and excellent energy efficiency by 2025.

With energy efficiency offering the most cost-effective route to energy savings, the CCC also wants the “energy efficiency retrofit of 29m homes to be a national infrastructure priority.“ However, any such programme would need to achieve far more than the 'Green Deal' retrofit scheme, which failed some five years ago.

Second, the UK is well short of the capacity and infrastructure needed to deploy heat pumps and hydrogen boilers, as envisaged in the report. Replacing natural gas boilers would mean boosting the UK's current 20,000 annual heat pump installations by a factor of 50, while also delivering a hydrogen boiler infrastructure within 15 years from a standing start.

While the CCC does not set government policy, its hugely ambitious report shows what's technically possible, based on strong data and authoritative analysis. It also identifies many of the barriers that would need to be overcome. Yet, despite plenty of ideas for how to achieve a zero-carbon built environment, the report doesn't include possible contributions from excellent whole-life building performance or even a circular building economy.

However, the CCC has now issued a net zero-carbon challenge for the UK built environment, and much more besides. It's now for government, clients and the construction and building maintenance sectors to consider how to respond.

The CCC's 275-page report 'Net Zero: The UK contribution to stopping global warming' is here.

Paul Reeve FIEMA CEnv is director of CSR at engineering services body ECA.