Achieving net zero will mean cities decarbonising existing infrastructure and buildings that was built way before energy efficiency was a key driver. Stuart McClaren of Atkins offers some ideas on how to do it.

Between 65% and 75% of the built environment that will exist in 2050 already exists today. In the context of net zero, that means a city’s challenge is how it will go about improving its existing built environment. In some respects, building new infrastructure, particularly buildings, to be net zero is ‘relatively easy’. What is more difficult is decarbonising existing city infrastructure that was built long before energy efficiency was a key driver. 

Below are 12 steps I believe cities need to take to decarbonise their infrastructure.

1. Develop your baseline, targets and plan. Baselines must be data-driven and targets science-based so that cities can have a high degree of confidence that their plans will actually deliver net zero outcomes. We must not deliver a theoretical net zero future, based on wishful thinking on behaviour change and new technologies. 

2. Understand your city as a ‘system within a system’. Pathways to a net zero future must be developed through an understanding of how your city’s system fits within the regional and national system. Regional spatial planning, local planning and the translation into masterplanning needs to be simpler and a greater line of sight created. 

3. Understand the innovation gap and map skills. The gap between a city’s 'business as usual' and what is needed to deliver net zero is likely to be significant. It is essential that cities maximise the opportunity to encourage and develop local skills and jobs ‘at home’ while developing an effective net zero value chain. 

4. Establish a net zero steering committee to guide the city’s transition and provide direction on integrating with national plans and systems. This should be a cross-discipline, cross-industry group focusing on all aspects of decarbonisation, identifying the innovation gaps tied to a city’s transport and energy systems, retrofitting and repurposing buildings and optimising underutilised land.  

5. Don’t over-rely on grid scale energy decarbonisation. Cities need an adaptive and resilient strategy around clean energy systems should grid scale clean energy capacity not be delivered as hoped. Strong leadership will be needed to make intelligent decisions on how to integrate with the national system and large local systems with any independence will also need to tell the system operators what its plans are for demand planning. 

6. Ensure your pathway delivers climate resilience. Cities are increasingly becoming susceptible to our changing climate. As such, cities must focus on ensuring their built and natural environments are not only resilient to climate change but they have in place what they need to be adaptive. Their pathway to net zero must not compromise this. 

7. Green your ageing infrastructure. Rather than demolish and remove the old – that takes time, money and carbon – great value can be gained from repurposing ageing infrastructure to create new urban greenscapes and pedestrians transport links. Cities should be constantly seeking to green its surrounds to address biodiversity net gain, wellbeing and social value.  

8. Make the vision real for communities. Take the lead on community engagement to help drive demonstrators of possible net zero interventions. These don’t have to be time and cost intensive; it can simply be repurposing a heavily trafficked area for a day or two to show people what a ‘pedestrianised city centre’ would feel like. 

9. Adopt a multimodal view of the future of transport. The fallout of Covid, its impact on society, the economy and our way of life provides the drive to challenge the status quo and look to new and bold multi-modal sustainable transportation strategies, enabled through combining planning with placemaking and digital infrastructure to decrease the need for commuting. 

10. Develop a city digital twin. This seems a big task but with the Centre for Digital Built Britain building a National Digital Twin, it is within every cities power to do; and the price of developing digital twins is reducing all the time. The goal should be to provide cities a means to model the impact of interventions and how best to optimise a city’s performance over the coming decades. 

11. Don’t forget the residuals. It is highly likely that interventions across all segments of a city over the next 30 years will not fully decarbonise the system. As such, cities must include credible plans for managing any residuals through carbon sequestration, be it nature-based solutions or technological.

12. Attract sustainable finance. Underpinning all the above 11 points is a city’s ability to finance its pathway to net zero. To attract investment, you need a credible plan, a good understanding of risk and reduction of that risk, sustained government (or local) policy supporting Return on Investment and a progressive and collaborative approach to procurement and value chain development. 

With technology and industry ever advancing, the way we view net zero is always changing. By adopting these 12 actions, cities can feel confident their approach is robust and adaptive.

Stuart McLaren is a technical director at Atkins.