Scaling Energy Modelling from Buildings to Urban Areas

Achieving climate neutrality requires scaling energy analysis from single buildings to integrated urban neighbourhoods. Using IES software, the POSIFIT project builds Urban-Scale Energy Model Digital Twins to virtually test decarbonisation strategies like heat pumps, renewables, and building upgrades. A Hungarian pilot showed this approach could theoretically cut district energy demand from 3,040 MWh/year to 217 MWh/year. By evaluating collective energy flexibility and storage, these digital twins support the creation of Positive Energy Districts. Ultimately, bridging building-scale data with district simulation gives planners a practical roadmap for smart, climate-neutral urban development.

Understanding how digital twins can support neighbourhood-scale decarbonisation

As Europe works towards climate neutrality, improving the performance of individual buildings remains essential. However, achieving large-scale reductions in energy demand, carbon emissions, and reliance on fossil fuels requires looking beyond single buildings and understanding how entire neighbourhoods perform as integrated energy systems.

This is where urban-scale energy modelling plays an increasingly important role.

Within POSIFIT, detailed building energy models have been developed using IES Virtual Environment (IES VE) to evaluate renovation strategies, energy-positive building concepts, renewable energy integration, and operational improvements. These models provide a virtual representation of how buildings consume and manage energy under different conditions, enabling informed decisions before investments are made. 

 

From Building Models to Urban Digital Twins

While building energy models are invaluable for assessing the impact of interventions at the individual building level, many of today’s energy challenges extend beyond a single asset.

Questions such as:

  • What happens if neighbouring buildings adopt similar renovation measures?
  • How much additional renewable generation could a district accommodate?
  • What is the combined impact of electrification, heat pumps, and energy storage across a neighbourhood?
  • How might future climate conditions affect urban energy demand?

require a broader perspective.

To address these questions, POSIFIT is scaling energy modelling from individual buildings to neighbourhoods through the development of Urban-Scale Energy Model Digital Twins (USEM-DTs). These digital twins expand detailed building-level simulations into a virtual representation of a wider urban area, allowing stakeholders to explore future scenarios and evaluate their potential consequences before implementation. 

The urban-scale models are developed using IES intelligent Community Design (iCD), which enables the creation of large-scale digital twins representing multiple buildings, energy systems, and their interactions within a district. 

Figure 1 Urban-scale digital twin of the POSIFIT Hungarian pilot developed using IES iCD.

 

Creating a Virtual Neighbourhood

Developing an urban-scale digital twin begins with collecting and organising information about the local building stock.

Building geometry, construction characteristics, energy systems, usage patterns, and local climate data are combined to create representative models of the surrounding area. The calibrated building energy models developed earlier in the project provide the foundation for this process, ensuring consistency between building-scale and district-scale assessments. 

Once established, the urban digital twin can be used to explore a broad range of scenarios, including:

  • Building envelope improvements
  • Renewable energy deployment
  • Heat pump adoption
  • Energy storage integration
  • Energy flexibility measures
  • Future climate change conditions

By testing these strategies virtually, cities, planners, and building owners can better understand the potential impacts of different interventions and identify the most effective pathways towards decarbonisation.

 

The Hungarian Pilot: Exploring District-Level Decarbonisation

One of the urban-scale digital twins developed within POSIFIT focuses on the Hungarian pilot site.

Starting from detailed building energy models created in IES VE, the project team expanded the analysis to include neighbouring residential buildings through an urban-scale model developed in iCD. This approach makes it possible to investigate how successful interventions applied to the pilot building could potentially be replicated across the surrounding district. 

Figure 2 Preliminary decarbonisation roadmap for the POSIFIT Hungarian pilot area.

To demonstrate the potential of the methodology, a preliminary decarbonisation roadmap was developed for the wider neighbourhood. Rather than representing an implementation plan, the roadmap explores a series of hypothetical intervention scenarios that illustrate how different technology combinations might contribute to reducing energy demand.

The scenarios included:

  • Building fabric improvements
  • Deployment of air-source heat pumps (ASHPs)
  • Installation of photovoltaic (PV) systems
  • Integration of battery storage
  • Expanded PV deployment across the district

The analysis showed how annual neighbourhood energy demand could progressively decrease from approximately 3,040 MWh/year in the baseline scenario to 217 MWh/year in the most ambitious scenario. While these results are illustrative rather than predictive, they demonstrate the value of urban-scale digital twins in understanding the potential benefits of coordinated neighbourhood-level action.

By evaluating intervention packages rather than isolated technologies, the digital twin helps stakeholders explore different pathways towards decarbonisation, identify promising strategies, and better understand the interactions between buildings, renewable generation, and energy storage systems.

 

Supporting Positive Energy Districts

Urban-scale modelling also supports one of the wider ambitions of POSIFIT: contributing to the development of Positive Energy Districts (PEDs).

Rather than optimising buildings individually, neighbourhood-scale digital twins enable the assessment of collective performance across multiple buildings and energy assets. This allows stakeholders to investigate opportunities for:

  • Increasing renewable energy self-consumption
  • Improving energy flexibility
  • Reducing carbon emissions
  • Enhancing local energy resilience
  • Supporting climate-neutral urban development

Through this approach, digital twins become a powerful tool for understanding how building-level innovations can scale into wider community benefits. 

 

Looking Beyond Individual Buildings

The transition towards climate-neutral cities requires more than efficient buildings. It requires understanding how groups of buildings interact, how energy is generated and consumed across neighbourhoods, and how local interventions can contribute to wider sustainability objectives.

By combining detailed building energy modelling in IES VE with urban-scale digital twins developed in iCD, POSIFIT is helping bridge the gap between building-scale analysis and district-scale decision-making. These digital tools provide a practical way to evaluate future scenarios, test renovation strategies, and explore pathways towards more sustainable and resilient communities.

As the project continues to develop and validate its methodologies across multiple pilot sites, it is demonstrating how digital twins can support smarter planning and accelerate the transition towards energy-positive neighbourhoods and climate-neutral cities across Europe.