A Vision of the Regenerative Future City

Prof. Dr. Gerhard Schmitt, ETH Zürich, Founding Director, Singapore-ETH Centre, discusses why cities are both causes and victims of climate change and critical considerations to achieve responsive and regenerative cities.


Excerpts from his keynote address during Systemair's event, "The future of sustainable HVAC – Trends and Innovations" held at the Sweden Pavilion in the Expo 2020 site in Dubai, UAE.

Prof. Dr. Gerhard Schmitt

The vision is simple: look for responsive and regenerative future cities. We know that cities today are the causes and the victims of climate change. For this reason, we must go beyond smart cities, and we must move towards responsive cities. We must go beyond sustainable cities and move towards regenerative cities. Most importantly, we must investigate responsive and regenerative enterprises for the good of society.

In the next 30 years, more than 2 billion more people will live in cities. Most of them will not be moving and living in Europe or the United States but in Africa and Asia. If trends continue, there could be more people on the African content by the end of the century than in Asia.

As such, technological and societal solutions are needed to accommodate the needs of the growing urban population in these hotter regions of the world. The governance of the future city, as well as the skills and knowledge base of the next generation of students and researchers are also critical issues to consider.

Cities – the problem and the solution

As I've said, cities are at the same time causes and victims of climate change. In countries like Sweden and Switzerland, we see what can be considered a luxury climate, which, in some respects, might even benefit from climate change and being exposed to warmer temperatures. Such countries have numerous lakes, which can serve as energy storage facilities, and they also tend to have a diversified energy mix.

We see a radically different climate in other parts of the world, providing a different set of problems and solutions. For example, every person in Singapore directly sees and feels the consequences of climate change, and they can do something against it. The massive use of air conditioning using electricity generated by burning natural gas takes a heavy toll on the grid. It also makes a strong case for decarbonisation by importing renewable energy from outside the region.

Every city has its own DNA and, thus, particular pathways to achieve a responsive or regenerative solution. To move towards responsive cities, smart cities are a good starting point. The term smart cities has a wide range of definitions. Many technologies contribute to it, from smart parking to smart mobility to smart water and energy supply. The early smart city trend has been technology driven. These initiatives were directed towards managing the city and not necessarily made for the citizens to participate in the process.

Monte Rosa Hütte interior (Valais, Switzerland)

Cities as sustainability models

There are not enough sustainable cities today, and it is only getting worse. Cities are responsible for 60-70% of global emissions and greenhouse gases, so we must do something about it. The emissions are not caused by energy production and use only – we must consider all the stocks and flows within a city.

A few examples: In Singapore, the reservoir at the city's centre, less than a 100 m above sea level, is a recreational area but is also used to store water and balance the temperature of the surroundings. In Switzerland, the Monte Rosa hut, almost 3000 m above sea level, is a testament to how much autonomy a building can have at that height. It is made almost entirely of wood, a fantastic lightweight material offering ease of transport. On the scale of districts, there are benefits of connecting buildings into networks for cooling or heating. Facilities that produce a lot of heat, such as research buildings, can pump excess rejected heat in the summer into the ground. In winter, this dynamic earth storage system can use heat pumps to provide energy for heating.

Photovoltaic (PV) electricity production, dynamic earth storage and CO2 reduction are examples for moving from sustainable buildings and neighbourhoods towards regenerative ones. For regenerative cities, its parts must produce more resources than they take. There are numerous examples of urban residences in Germany and other European countries that produce almost 3 times more electricity than they consume over the course of one year. This is not in the future - it is happening now.

Cities and civic engagement

Today, many cities have recognised that citizens demand to be involved in developing their cities. In a responsive city, responsive groups, and individuals should be involved in the planning and the management of their habitat. They express what they need and what they suggest. They use smart city technologies to communicate their ideas. Ideally, they have access to the same big data reservoirs of their cities as the professional planners and designers.

Such systems can be observed in Switzerland with its strict bottom-up direct democracy. In Zurich and other Swiss cities, citizens suggest what should be done in the city in constant communication with politicians and political parties. Based on a different political system, Singapore is developing a smart city and a smart nation. While introducing technology in every part of city management, it seeks consultation and advice from its citizens. Vienna and Scandinavian capitals that rank high in liveability benefit from a strong civic engagement of their population.

Civic engagement is fundamental because people living in cities are aware what is needed. They know the temperature; they know what is working and what is not. If they have the instruments to extract and communicate urban data and information, technology companies, such as HVAC companies, can work much better.

The importance of responsive and regenerative enterprises

Responsive and regenerative enterprises should support these overarching efforts. The Cooling Singapore project is one example where people play an active role in the decision-making process on what should be changed in the city. To prepare the project, in surveys citizens explore options and propose initiatives such as green streets. They suggest in which options to invest tax money. It is impressive how they select long-term over short-term beneficial solutions. They follow up on details and suggest where in their neighbourhood the initiatives should be implemented. This collaboration between a city and its population, supported by smart technology, is important.

In cooling cities in a regenerative way, we must identify active and passive heat sources and replace them with renewable, less or no heat emitting solutions. Air conditioning is often, but not always the solution, as in many places it is not possible or desirable. 

While investigating new measures, we must remember that the problem has many dimensions. Urban topology, urban geometry, building materials, industry, commercial enterprises, transportation, and energy production contribute to the urban heat island effect. For a tropical climate like Singapore, there are many mitigation measures, such as vegetation, water bodies, shading, optimisations in materials, surfaces, fossil-free transportation and import of renewable energy.  

Fundamental changes are needed, and this is not easy. One cannot just turn down the thermostat for an entire city. It is therefore necessary considering all mitigation efforts in terms of cost and their impact on the environment, health, and economy. If a city decides to lower the temperature and increase the outdoor thermal comfort, it must consider factors such as materials, energy, vegetation, shading, transport, urban geometry, and water features, to name a few, and how they are interlinked. For this, digital twins emerge as necessary computation support.

Why build digital twins

Simulations help define the best cooling options by developing "what if" scenarios. By building digital twins, we can study the effectiveness of different initiatives, be it District Cooling or electric vehicles. Models and effective visualisations can help show the impact of individual factors and measurements on the future city. 

For Singapore, we built an interactive visualisation for citizens and decision makers to experience the dynamic behaviour of the city in the course of an entire day: they watch the dynamics of the urban heat island effect at 2 am compared to 5 or 6 am; they observe the impact of rush-hour traffic and its emissions into the urban system; they follow the breeze from the sea around 10-11 am that slightly cools parts of the city and the temperature rise from 1 to 3 in the afternoon; they see that at 4 or 5 pm people drive home, adding more heat into the urban system and that at night, heat from the buildings radiates out and makes it uncomfortable to sleep. These are common problems that many cities have, and advanced HVAC companies provide some of the solutions to solve them. Using digital twins, we can arrive at scenarios to continuously improve the city.

In summary, the vision of regenerative future cities requires an informed society, a responsive governance, regenerative enterprises, integration of re-use and recycling, new jobs in nature-based cooling and heating, more public-private industry partnerships, and most important: citizens to support this development.