Decarbonising buildings: being clear about definitions 

Building decarbonisation is all about reducing and ultimately eliminating the greenhouse-gas emissions associated with how buildings are designed, built, operated and renovated. 

Operations are the most obvious source of emissions, through the energy we consume to heat, cool, ventilate and illuminate spaces. However, the upstream and downstream factors are less visible. These include the materials we purchase, the equipment we replace, the call-outs avoided with better maintenance or the waste we keep out of landfill. All of these impacts are covered by three scopes, as defined by the GHG Protocol:

• Scope 1 covers direct on-site emissions such as those generated by gas boilers or back-up generators. It can also include less intentional emissions such as refrigerant leaks.
• Scope 2 concerns purchased electricity and heat.
• Scope 3 spans the wider value chain, including procurement, logistics, equipment life cycles and end-of-life processes.

Taken together, these three scopes describe not just a technical challenge but a managerial one. Here, we have a network of decisions that, if made coherently, can significantly alter the emissions curve for an asset portfolio or city. 

Moving from policy to practical outcomes

Across Europe, public policy demands higher performance from buildings, as well as realistic renovation targets and clear milestones for new builds. The revised EPBD1 establishes national renovation plans and timetables, setting a target of zero emissions for new public buildings from 2028 and all new buildings from 2030. Meanwhile, the Renovation Wave1 initiative aims to at least double renovation rates and upgrade 35 million buildings by 2030. 

These measures form part of the broader European Green Deal scheme, where “Fit for 55”2 turns ambition into a binding legal commitment. And following the European Parliament’s 2024 vote on the EPBD3, it has never been clearer that buildings represent the front line when it comes to tackling energy security and climate issues, as well as the challenge of affordability.  

However, policy momentum does not complete projects on its own. Building owners, facilities operators, private businesses and public services all face tough choices when it comes to funding and how to coordinate or integrate their actions. This is where robust, practical solutions and an experienced integrator make all the difference.

Equans’ solutions: a 4-lever approach

Our decarbonisation solutions are designed around a pragmatic sequence. First, optimise what you have. Then, electrify and produce clean energy. Thirdly, recover any waste energy. And finally, tighten the value-chain loop. In practice, each of these four steps reinforces the others.

1. Optimise energy performance

Undeniably, the cheapest and cleanest energy is the energy you don’t use. This is why we start with controls and scheduling. This means, for example, making sure that ventilation isn’t running at night in an empty building. It could also involve the implementation of presence sensors for lighting and HVAC. Building Management Systems (BMS) deliver the greatest impact when they shift from weather-based scheduling to occupancy-driven controls. Analytics layers can flag inefficiencies such as simultaneous heating and cooling or misaligned schedules, enabling quick corrective action. We also add LED retrofits and leak detection for immediate savings across Scopes 1 and 2.

The entire approach is supported by accurate metering and facilities teams that are empowered to tackle any issues. It is also covered by performance contracts to ensure incentives and outcomes are firmly aligned.

2. Electrify processes and add renewables

We cut direct emissions by switching from fossil-fuel heating to high-efficiency heat pumps or electric boilers where appropriate. On the supply side, we deploy rooftop or on-site PV for self-consumption, supported by storage and smart controls. Geothermal or solar thermal energy, or well-sized cogeneration using low-carbon fuels, can be implemented to stabilise costs and improve long-term resilience. The key is effective integration. Hospitals and retail parks, for example, will not share the same load profile or constraints.

3. Reduce Scope 3 emissions with circular practices

Scope 3 relates to how an organisation purchases and moves around. We extend asset life through high-quality maintenance, reducing call-outs and associated mileage and priortitising repair and reconditioning wherever possible. In parallel, we set low-carbon procurement criteria that suppliers can meet; emergency lighting blocks (BAES), for example, are often suitable for reconditioning with warranty support5. And when these circular practices are embedded in performance-based contracts, this approach to Scope 3 eventually becomes business as usual.

4. Reuse waste heat and optimise thermal flows

Many sites waste a lot of useful energy. Places like data centres or supermarkets are rich sources of recoverable heat. Instead of letting it escape, we capture it for reuse on site, raising the temperature where required and routing it through the BMS to cover heating or domestic hot water needs. Where it improves the profile, we add thermal storage, including high-temperature modules, and connect to local heat networks. In data centres, immersion cooling cuts cooling loads and makes waste-heat recovery easier. The result is simpler electrification and lower dependence on the grid.

The role of the carbon manager covers all four of these levers and requires exceptional talent. They need to act as a bridge between energy-performance teams and procurement functions, as well as liaising with suppliers to ensure investment in low-carbon solutions. They then need to translate data into decisions and convert strategy into daily action.