Digital Twins: The Virtual Key to Sustainable Cities
By James Morton
Step into the heart of a modern city and you’ll find a world of complexity humming beneath the surface. Buildings, roads, railways, power grids, water pipes, traffic flows, and microclimates all interact in subtle, sometimes unpredictable ways. For city officials and developers tasked with delivering net zero and climate resilience, this complexity can be a formidable challenge. But a new wave of digital technology is changing how we design, build, and manage our built environment. At its core is the digital twin: a virtual replica of a physical asset, dynamically linked to the real world, and set to become the nerve centre of sustainable cities everywhere.
What Is a Digital Twin—and Why Does It Matter?
A digital twin is far more than a static 3D model. It is a living, breathing virtual counterpart of a building, street, or entire city, updated with data from sensors, user feedback, weather stations, and more. At its best, it allows planners, engineers, and building operators to simulate, analyse, and optimise performance—long before the first brick is laid, and throughout an asset’s operational life.
The idea may sound futuristic, but it’s rapidly becoming a practical reality. Take Singapore, often hailed as the world’s “smartest city.” Here, the government has developed a country-scale digital twin, mapping every building, road, and green space. Planners use the model to test everything from energy demand and public transport flows to flood scenarios and the impact of new green infrastructure. The city’s digital twin isn’t just a planning tool—it’s a dynamic sandbox, where sustainable solutions can be trialled virtually, optimised, and then rolled out in the real world with far greater confidence.
Design Smarter, Build Better
In the world of new developments, digital twins are rewriting the design process itself. Imagine an architect tasked with creating a new office block. Instead of relying solely on standard calculations and best guesses, they can now use a digital twin to predict exactly how the building will perform—optimising the shape, orientation, glazing, and insulation to minimise material use and slash future energy bills.
Before a single foundation is poured, the twin can simulate everything from daylight access and thermal comfort to the embodied carbon of different construction options. Should the team specify recycled steel or low-carbon concrete? What happens if they increase the size of south-facing windows, or add a green roof? Each decision can be tested in a risk-free virtual environment, letting the team design out waste and inefficiency from the very beginning.
Operation: The Living, Learning Building
But the real magic begins once a building—or a whole campus—is up and running. With the right sensors and integration, digital twins turn data into actionable insights. They become the eyes and ears of facilities managers, constantly monitoring HVAC systems, lighting, water use, occupancy patterns, and even air quality.
A compelling example comes from a university campus in northern Europe. By integrating its digital twin with the building management system, the facilities team was able to model how small tweaks in heating, ventilation, and cooling would affect both comfort and energy use. They discovered that reducing HVAC operation during certain hours, with only minimal impact on indoor conditions, could cut annual energy bills by 10%. Those savings were reinvested into further upgrades, creating a virtuous circle of efficiency and climate action.
Elsewhere, digital twins are being used to spot maintenance needs before they become failures, optimise cleaning schedules, and even support post-pandemic “healthy building” protocols—all while providing a single source of truth for decision-makers.
The City-Scale Sandbox
The true promise of digital twins lies at the city scale. When planners can simulate an entire urban environment, they gain a risk-free laboratory for climate action and resilience.
Consider a city grappling with urban heat islands and poor air quality. With a digital twin, planners can test the effect of planting thousands of new trees, adding green roofs, or rerouting traffic before committing public funds. Flood risk? Simulate rainfall events of increasing severity, trialling new permeable paving or wetland creation to protect vulnerable districts. Need to hit carbon targets? Test the combined impact of solar rooftops, active travel infrastructure, and electric bus fleets on city-wide emissions.
This approach isn’t just theoretical. Cities from Helsinki to Shanghai are building their own digital twins, collaborating across public and private sectors to use data, simulation, and digital storytelling to accelerate sustainable change.
The Power—and the Caution
Digital twins do not, of course, guarantee perfect outcomes. The quality of their insights depends on the quality of data, models, and the commitment of teams to act on the findings. Privacy, cybersecurity, and digital inequality must all be taken seriously.
But with those caveats in mind, the value is hard to ignore. Developers and city officials alike now have at their fingertips a powerful tool: a risk-free environment to innovate, optimise, and collaborate—helping ensure that every decision, from the materials chosen to the transport network designed, is grounded in real-world evidence and aligned with climate goals.
Conclusion: From Vision to Reality
The challenge of sustainable urbanisation will not be solved with technology alone. But digital twins are fast becoming an essential part of the solution—a way to see around corners, learn from the past, and design for a future where cities are not only smarter, but greener, healthier, and more liveable.
As this technology continues to evolve, the opportunity is there for every city and every project: to embrace digital twins as the virtual key that unlocks a new generation of sustainability—one decision, one building, and one community at a time.
References:
Singapore Land Authority. (2024). Virtual Singapore: The City’s Digital Twin.
C40 Cities. (2023). Digital Twins for Urban Climate Action.
Helsinki Smart City. (2024). Helsinki 3D+ City Model and Digital Twin.
World Economic Forum. (2025). Digital Twins for Cities: A Guide to Implementation.
Sustainable Stories Interviews, 2025.