written by Francesca Bruno

How do you define sustainability in your practice?

    We invented the term ‘supergreen’ because we were highly committed to pursuing sustainable design in our work. Our understanding of green architecture is not typical of the greenwashing that is found in many green designs. It is about a realistic, integrated approach to architecture. Christoph, the founder of ingenhoven architects, grew up in a time where young people were becoming increasingly frustrated with the thinking of the older generation – similar to today. It was around this time that the Green party emerged in Germany. So it was a natural reaction to become more conscious of our environment, and this became an integral part of our thinking in architecture.

    We believe that you shouldn’t just build a building based on beauty, style, or your personal idea of architecture. Instead, you should create something that is in dialogue with its surroundings, with the community, and with the planet as a whole. Sustainable rating systems like LEED concentrate a lot on energy consumption and reduction. For us, ‘supergreen’ means more than energy consumption and social sustainability; it represents a big-picture approach that tries to address all aspects of sustainable design. These include carbon neutrality, replacement, public space, resilience, and urban greenery.

How is your concept of ‘supergreen’ reflected in the recent Kö-Bogen II development in Düsseldorf?

    Kö-Bogen II is mainly a retail development, which gave us the unique opportunity to cover substantial parts of the building with hedges – a green facade. In terms of ‘supergreen’, the hedges improve the city’s microclimate: they reduce the urban heat island effect, close the gap in the water cycle by storing rainwater, bind carbon dioxide and dust, absorb noise, support biodiversity, and support people’s general wellbeing.

    There is a lot of talk about green facades being wild and uncontrollable. Kö-Bogen II is a good example of how landscape art can also be applied to a building. You can't control every leaf but of course you can give it a shape.

The facade of Kö-Bogen II is quite distinctive. How does it react to its surrounding urban environment?

    Kö-Bogen II is located between two architectural icons: the Dreischeibenhaus by Helmut Hentrich and Hubert Petschnigg (1960) and the Schauspielhaus by Bernard Pfau (1970). The Hofgarten, a big, beautiful park, lies behind it. Until a few years ago, it wasn’t possible to experience these buildings or see the park from the Schadowstrasse shopping boulevard. So one of our first ideas was to break up the volume and design a shape that opened up the view.

    Kö-Bogen II enters into a dialogue with the clear austerity of the Dreischeibenhaus and the lightness and buoyancy of the Schauspielhaus – a contemporary answer to these two historic landmarks, bold without being overbearing. Its dynamic green facades enable the new building complex to oscillate in a deliberate indeterminacy between city and park.

You work on many international projects, including Marina One in Singapore. How do your sustainability strategies differ based on the region of the world?

    Wherever we build we look at many factors, including the surroundings, setting, climate, and traffic. Singapore requires 100% greenery replacement, meaning you have to replace 100% of your footprint with a publicly accessible green landscape. If you are building on 200,000 square metres of land, you have to give back 200,000 square metres of land – that’s quite a challenge! Germany doesn’t have such regulations. With Marina One we managed to give back 170% in public space by using terraced gardens to create a green landscape on multiple levels inside the building.

    If you compare Germany and Singapore in terms of climate, the sun and humidity values are very different. German winters see very little sun, whereas in Singapore, the sun is always above you. In Singapore, cooling and dehumidifying the air use up a lot of energy. In Germany, it’s dramatically less. So different systems are needed. It’s about your exposure to the environment – compactness is important when developing buildings in Europe or the northern hemisphere, because it's important to keep things close and not expose yourself to the cold air. Marina One is less compact. We included air gaps and air wells enhancing ventilation and air circulation. We even lifted the building up to create an air gap inside the high-rise, so that when the upper parts of the tower facades heat up, cooler air is drawn into its green heart.

Renovating existing buildings instead of constructing new ones is one way to reduce embodied carbon in a building. What can you tell us about embodied carbon in your architecture?

    You have to run an energy-efficient building for 75 years to get to the amount of CO2 already embodied in its construction. To deal with this fact is a huge challenge for architects. Reusing existing buildings is a task we are increasingly confronted with. If you build new, you have to invest in the most efficient construction in order to limit embodied carbon. This includes things like using recycled steel and concrete, or materials produced with green energy, as well as integrating green facades. 

    Another important aspect is city planning. For example, Marina One is a mixed-use development with office, retail, and residential space with direct access to the metro station. This limits car usage and CO2 emissions. Looking at the wider context, in many cities over the last decades, residential areas were separated from working areas – everything became disconnected. We have to change that. Short walking distances have to become the new normal.

Do you think there are any practices in sustainable architecture that are labelled sustainable but are, in reality, ineffective and serve as an example of greenwashing?

    Of course. There are many instances where there is a bit of green panelling added to a building so that it looks like green architecture, but the concept hasn’t been thought through, so that it seems like more of an afterthought added merely to score points with the LEED rating system.

    We search for clients who have a deep understanding of sustainability, who want to change things for the better. For sustainable architecture to develop further, awareness needs to come from all sides. It’s not just about the architects, engineers, and clients, but also about the users. We need sustainable thinking and practice. I think the younger generation is working towards that, but there is still a lot of outdated thinking that gets in the way.