Green spaces in cities are of particular importance in the face of ongoing urbanisation and the anthropogenic climate change. Urban greenery affects the physical and mental health of citizens. It reduces the immediate effects of global warming such as heat islands and improves the thermal comfort of cities. In addition, plants have an impact on particulate emissions and the carbon balance. Finally, urban green is an important part of the cultural heritage and the identity of a city. 

In the framework of the Smart City Center of Excellence, the GreenTwins project addresses the issue of urban greenery and how it can be better taken into account in planning processes for sustainable and more democratic cities. The focus is on urban digital twins: they can be used to enable comprehensive data exchange and can include models, simulations and algorithms that describe their real counterpart, its properties and behaviour in the real world. Digital twins have only arrived in urban planning in the last few years. The example of the digital replica of Singapore is certainly one of the best known. The cities of Tallinn and Helsinki are consistently building their digital twins to digitalise and optimise planning processes, while the national level digital twin of Estonia was presented just recently.

The modeling of the natural environment in urban digital twins is so far underdeveloped compared to the built environment. Also, participatory and collaborative processes have been given little consideration in the application of digital twins. Yet these digital tools offer great opportunities. The GreenTwins project develops a dynamic layer of green infrastructure in the urban digital twins of Helsinki and Tallinn. Additionally, it creates three new user interfaces to urban digital twins in order to harness the potential of urban digital twins in advancing planning processes and democratic decision-making. Accurate modeling of the natural environment is essential for citizen participation, as non-professional stakeholders often do not have the necessary expertise or planning language background. Due to this barrier, many people are excluded from participatory processes or have problems in interpreting professional planning representations correctly. 

This is where GreenTwins comes in and develops new approaches by an outstanding team of scientists and experts from the partner cities of Tallinn and Helsinki. A CityHUB will be co-developed as a built structure in Tallinn to serve citizens, planners, decision-makers, city administrators, businesses and researchers. Additionally, two applications will be developed in the project. The co-planning app provides additional information and the opportunity for citizens to directly participate in planning processes. The urban tempo simulation app supplements simulations and visualisations by enabling virtual spatial experience in the CityHUB but also on desktops. For the first time, the inventory of existing species and their characteristics will be included as a dynamic digital layer in digital twins. The focus is on the interplay between the built and natural environment, the change of plants over the seasons and over the years. The impacts of vegetation  on our neighbourhoods and the cityscape, on urban space and microclimate, as well on our well-being. With the help of the visualisations and involvements, the complexity of urban planning can be reduced and more democratic participation and Citizen Science will be enabled and encouraged.

The GreenTwins project contributes to the development of participatory urban planning, which relates to one of the global Sustainable Development Goals (SDG 11) provided by the United Nations. The on-going development of urban digital twins is creating new opportunities for better citizen engagement and the improvement of democratic processes in the civic society.

The GreenTwins smart city pilot is financed by the European Regional Development Fund and the Estonian Ministry of Research and Education.

Fabian Dembski is a research professor at TalTech, Academy of Architecture and Urban Studies and a project leader of GreenTwins together with Kimmo Sakari Lylykangas (TalTech) and Aija Staffans (Aalto University).

Project Consortium: 

Tallinn University of Technology (TalTech), Estonia | Aalto University, Finland | The Cities of Tallinn and Helsinki

Collaboration Partner: 

High-Performance Computing Center Stuttgart (HLRS), Germany