Zero Carbon Accelerator: why it is about people, not just carbon

Zero Carbon Accelerator: from cold buildings to comfortable spaces

As London strives for net zero by 2030, the Mayor of London’s Zero Carbon Accelerator is showing how a coordinated, people‑centred approach can turn complex decarbonisation challenges into scalable, practical solutions that could work anywhere. Mott MacDonald technical director for sustainability Eszter Gulacsy and head of building decarbonisation Kevin MacLennan explain.

Helping organisations to decarbonise and support the city’s goal of reaching net zero by 2030 was the primary ambition of the Mayor of London’s Zero Carbon Accelerator. Since its launch in September 2024, Mott MacDonald has led a network of specialists and worked alongside the Energy Saving Trust to deliver on those aims and, in doing so, has built up knowledge that could benefit decarbonisation in other regions too.

Conversations about decarbonising public buildings often default to targets, carbon budgets, compliance frameworks and investment thresholds. These metrics matter, but they are not the reason the work is urgent. The real driver is people, those who live, learn, work and receive care in public buildings every day. The Zero Carbon Accelerator was created to turn London’s ambition into meaningful, lived outcomes, such as warmer rooms, healthier environments and lower energy costs.

The Zero Carbon Accelerator is vital to London’s 2030 target with buildings responsible for 67% of the capital’s carbon emissions. The programme focuses on overcoming persistent barriers to running decarbonisation initiatives successfully, such as limited in-house capacity, complex procurement processes, challenging project business cases and fragmented funding options.

The support led by Mott MacDonald under the Zero Carbon Accelerator has included programme management, technical guidance, skills development, project planning and financial insight, helping local authorities, health providers, education settings and housing organisations accelerate their decarbonisation journeys.

Mindset shifts

Over the past year, the Zero Carbon Accelerator has seen how mindsets shift when conversations are rooted in lived experience rather than carbon numbers. Carbon is the measure, comfort, affordability and wellbeing are the outcomes and when the outcomes improve, the carbon reductions follow.

Across London, too many homes and public buildings remain inefficient, costly to heat and uncomfortable to occupy. Decarbonising heat is not simply a technical exercise involving the removal of boilers and installation of heat pumps, or the expansion of low carbon heat networks. It is fundamentally about creating thermal comfort that is accessible and equitable. Schools, libraries, care homes, community centres and social housing depend on reliable warmth to support learning, dignity, health and connection. In these settings, comfort is not a luxury but vital for wellbeing.

The Zero Carbon Accelerator has already supported a growing pipeline of projects across London, demonstrating how coordinated technical, financial and strategic guidance can unlock momentum and turn ideas into deliverable programmes. These early projects show the potential for transformation when organisations receive structured support and a shared framework for delivery.

Accelerating estate-wide decarbonisation in Lewisham

The Pepys Estate in Deptford, which is one of London’s largest council estates, faces significant fuel poverty challenges and is an example of how the Zero Carbon Accelerator is driving change.

Planning and procurement support for an estate-wide decarbonisation strategy was provided by the Zero Carbon Accelerator to address gas safety, outdated infrastructure and prepare for future heat network connections. The work explored options such as ground and air source technologies, heat and cooling network integration and smart energy systems across both high-rise and mid‑rise building types. Alongside improving energy efficiency and reducing carbon emissions, the project will result in lower fuel bills, improve indoor comfort and support a just transition for residents. For the Zero Carbon Accelerator it has created replicable templates and guidance to help accelerate decarbonisation across other London estates.

The real driver is people, those who live, learn, work and receive care in public buildings every day.

Moving from learning to acceleration

After 12 months of learning on the Deptford project and other schemes, the Zero Carbon Accelerator is now focusing on accelerating delivery. Learning alone doesn’t cut emissions, action at scale does. The Zero Carbon Accelerator is shifting from isolated pilots to coordinated portfolios, applying standardised, repeatable approaches across dozens and hundreds of buildings; in many cases coupled with GLA frameworks that improve access to delivery partners. Cutting friction by streamlining designs, simplifying procurement and speeding the path from feasibility to shovel-ready projects and aligning teams, asset managers, finance leads and communities behind shared outcomes. In doing so, the Zero Carbon Accelerator moves from simply supporting delivery and starts driving it, becoming a true delivery engine.

Speeding up delivery

Acceleration now depends on a series of practical shifts. High quality asset level data is essential, creating a single source of truth about building fabric, systems, energy use, metering and maintenance history. With this foundation, organisations can prioritise interventions that deliver the greatest impact and standardise design approaches to avoid duplication.

While improving the building fabric remains essential, practical constraints such as limited funding or fixed delivery timescales sometimes make technological solutions the most viable short‑term option for achieving desired outcomes. In many cases, the greatest impact comes from combining technologies, such as pairing solar PV with battery storage, or integrating solar PV, batteries and heat pumps as a coordinated system.

Procurement must focus on outcomes rather than transactions though. The Zero Carbon Accelerator can help establish the necessary measurement and verification frameworks to make these approaches consistent across portfolios. Finance models should match asset lifecycles and whole life performance, blending grants, low-cost borrowing and energy performance models where appropriate.

Skills development is equally critical. Commissioning, performance monitoring and seasonal recommissioning should become standard practice, replacing outdated “install and walk away” approaches. The Zero Carbon Accelerator can champion training, standards and performance assurance across delivery partners.

Blueprint ready 

The work over the last year has shown that when technical expertise is paired with a people-centred approach, decarbonisation becomes practical, repeatable and scalable. While a challenging financial climate exists, all three of these attributes are likely to improve risk profiles and reduce capital cost.

The barriers faced in London are the same challenges confronting other regions across the UK. What the Zero Carbon Accelerator demonstrates is that many of these can be overcome with standardised delivery pathways, outcome-based procurement and a focus on improving comfort, health and affordability.