Achieving net zero

To achieve net zero, schools must rapidly curtail their carbon emissions. Initiatives such as the UKGBC’s Whole Life Net Zero Carbon Roadmap for the Built Environment and the UK Net Zero Carbon Buildings Standard provide essential guidance. So what should schools be mindful of? Tom Wigg from the UK Green Building Council shares valuable insight.

In 2023, we witnessed the hottest year on record. Climate change is no longer a distant concern for the future generations, it is a present reality that is profoundly impacting both humanity and ecosystems.

Whilst the consequences of man-made global heating are already manifest, we have the opportunity to minimise the worst long-term impacts if we can keep the temperature rise to within 1.5°C of pre-industrial levels.

Greenhouse gas (GHG) emissions (those that trap the sun’s energy in the atmosphere) released by anthropogenic processes are the cause of the rapidly increasing air and sea temperatures worldwide.

We must reduce global emissions to net zero by 2050 – where an equivalent amount of emissions are removed from the atmosphere than are released each year – if we are to stand a chance of keeping the temperature rise to within that 1.5°C threshold.

Carbon in buildings

Based on work by the Intergovernmental Panel on Climate Change (IPCC), the world’s buildings were the cause of 21 per cent of global GHG emissions in 2019.

If considering just energy-related emissions, this proportion rises to 39 per cent, according to the World Green Building Council. Any way you frame it, buildings are a significant hurdle we must overcome if we are to get to net zero in time.

According to the UK Government, schools and universities are responsible for 36 per cent of public sector emissions, and schools spend £630m a year on energy. For this reason, improving the performance of our education buildings could provide a strong opportunity for both reducing emissions and operating cost to the taxpayer, as well as allowing pupils a chance to engage in and learn from our built environment’s net zero transition.

The UK Green Building Council’s Whole Life Net Zero Carbon Roadmap for the Built Environment, which was launched at COP 26, was the first attempt at creating a coordinated decarbonisation pathway for the UK built environment that aligns with our carbon budget (i.e., the maximum quantity of carbon that can be emitted en route to net zero).

This includes key actions that must be taken and milestones achieved between now and 2050, with the ultimate goal of reducing emissions to nearly zero.

Cutting carbon

For schools, this means adopting robust strategies to significantly reduce both operational and embodied carbon. Operational carbon describes the emissions that result from a building’s day-to-day operation.

These are primarily from energy used by the building, such as from burning gas or consuming electricity, but also things like water use.

Embodied carbon emissions are those which are emitted during the extraction, processing, manufacture, transport, construction, or maintenance of the building and its constituent materials and products, both before it is built and when it is in use.

One effective approach for schools to address operational carbon emissions is by reducing energy demand. Implementing solutions such as double glazing, cavity wall insulation, mechanical ventilation with heat recovery (MVHR) and LED lighting can reduce heat loss and improve energy efficiency. Similarly, replacing gas boilers with efficient electric heat pumps minimises the amount of energy needed to generate heating and hot water for a building.

Another solution for reducing operational carbon is to shift away from burning fossil fuels and embrace low-carbon alternatives.

For example, using electricity instead of gas. The rationale behind this lies in the declining carbon intensity of the UK grid over the last two decades, reducing by more than 70 per cent in the last 10 years alone. By transitioning away from coal and gas generation to renewable alternatives like wind and solar, the UK’s electricity system is aiming to be zero emissions by 2035. Switching from a gas boiler to an electric heat pump doesn’t just reduce demand but leverages the decarbonising grid to further reduce operational emissions, with a clear route to net zero when electricity is zero carbon in future.

This future zero carbon grid is the cornerstone of us delivering against our national net zero goals, by supporting the decarbonisation of buildings, transport, manufacturing, and other industrial processes.

But buildings have an important role to play in the grid’s transition. Firstly, buildings can reduce their energy demand, as indicated by the UKGBC Roadmap, by approximately 60 per cent.

However, the contribution doesn’t end there. Buildings also need to contribute to the additional generating capacity by installing onsite renewables such as rooftop solar PV panels.

Moreover, buildings need to operate in a way that aligns with a grid dominated by intermittent wind and solar power. This involved responding flexibly to availability of renewable electricity. By doing so, buildings become integral players in the transition toward a sustainable and resilient energy system.

Reducing a building’s demand for energy by implementing these solutions often has an embodied carbon impact, however. Producing materials and products like insulation, windows, and heat pumps uses substantial amounts of energy which in turn releases greenhouse gas emissions. It is for this reason that both embodied and operational carbon, as well as energy demand, must all be considered together when seeking to decarbonise our built environment.

Defining ‘net zero’

What ‘net zero’ means for an individual building remains dynamic and ever evolving. Initially defined by the UKGBC’s framework definition (which brought together 70 industry experts in one of the UK’s first efforts at creating a definition), subsequent initiatives like LETI’s Climate Emergency Design Guide have further enriched this understanding.

For schools, these guidelines offer best practice targets related to building fabric, services performance, energy demand and embodied carbon – critical insights that should inform building design, delivery, and operation.

The next step on this journey of defining net zero for buildings comes in the form of the forthcoming UK Net Zero Carbon Buildings Standard (NZCBS). The Standard is a cross-industry initiative between many of the key professional institutions and industry bodies in the UK built environment.

With five task groups and 14 sectors groups comprising over 350 representatives, the NZCBS will provide an extensive list of criteria that a net zero building needs to meet, as well as a robust process for verifying that it does.

In addition to this, it will set building-level limits for operational energy consumption and embodied carbon that are derived from our carbon budgets.

It is these ‘science-based’ limits, including those for schools, that will ensure any building wishing to claim to be net zero is reducing its emissions in a way that is compatible with the UK economy’s transition to net zero by 2050.

Learning from others

Whilst the NZCBS will help the schools sector understand what performance new and existing buildings need to achieve to do their part in this journey, other initiatives are focussing on how to deliver this in practice.

Arm’s-length body to the Department for Education (DfE), LocatED, recently ran a pilot Net Zero Accelerator for schools, which sought to ‘demonstrate the commercial viability of a range of decarbonisation interventions.’

In future, it is hoped the learnings from this exercise will establish a model for private and public sector partnership to realise net zero for the school estate.

This accelerator forms part of DfE’s wider strategy for sustainability and climate change.

Along with the institutions, organisations, and ambitious private sector companies involved in the range of initiatives seeking to define and deliver net zero buildings in the UK, we at UKGBC look forward to continuing to work with and support DfE in achieving the goals of their strategy and, ultimately, transitioning to a sustainable and net zero school estate by 2050.