Prof. Inger Andresen is a professor in Integrated Energy Design at the Norwegian University of Science and Technology. She has more than 30 years of experience in research and development within the fields of energy efficient buildings, renewable energy, and low carbon buildings. She focuses on developing concepts and solutions for zero emission buildings and plus-energy houses. Andresen led the research on pilot and demonstration buildings within the Norwegian Research Centre on Zero Emission Buildings, and was involved in the Research Centre on Zero Emission Neighbourhoods in Smart Cities, where she led the work on pilot projects and living labs. Currently, she is the coordinator of the EU-funded project ‘Climate Positive Circular Communities’.

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What is the main challenge in (re)constructing net-zero energy buildings?

Inger Andresen: I’d say the biggest challenge is costs. Even if the solutions have positive lifecycle costs, the initial costs are too high for many people, and the financing options are still not great in many countries. Naturally, there are other challenges, such as skills and knowledge. The technical solutions are often not well integrated into what people need or want and can be too complicated to use. For example, during one of our projects, we tested smart home systems that help reduce the energy consumption. These included a panel where everything could be controlled – including turning off lights or other electronic devices while people were out of the house. People were often too afraid to use it because they worried it would also turn off their fridge, for instance. The solution might seem simple and easy to use, but in practice it does not work well.

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Is it possible to turn an old building into a net-zero building? How, and why, isn’t it done on a scale?

Inger Andresen: It is certainly possible to turn an old building into a net-zero energy building, but it can be difficult in many cases. In some buildings, such as heritage buildings, it might not even be viable. In fact, this is why we started looking at the issue at a neighbourhood level rather than making changes building per building. It might not even be the smartest thing to do, to consider individual buildings, because some can compensate for others at a neighbourhood level. Furthermore, to renovate a building, it can be difficult for people to find the best solutions – because it differs from building to building. That’s why we are developing one stop shops, where we can offer people the full package. The shops combine different suppliers and services, so they can offer the best options to the community. We need to offer more of these services to make it easier for people. In fact, every country should establish these.

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In your projects, you have worked with demonstration sites across different European climate zones. Are there particular building types, climates, or renovation contexts where net-zero solutions are working well - and others where the concept still struggles to be cost-effective or replicable?

Inger Andresen: When we find a neighbourhood where all the buildings are the same, it’s easier to renovate them, because we can offer the same solutions at the same time – which makes it more economical and efficient. There are differences depending on the climate – due to temperature, solar accessibility, culture and so on, but there are also a surprising number of similarities. The specific strategies might be different, but the principles are comparable. The global principle is to reduce the need for energy and to supply renewable energy sources locally.

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What are the practical barriers development keeps running into?

Inger Andresen: Financing is the main issue, combined with codes and regulations. It is the carrot and whip principle. Regulations are the whip and the financing would be the carrot. However, there could be other incentives for people other than financing. We could offer faster approval of permits, for example. Then there are many soft criteria, such as liveability and architectural preferences, that need to be taken into account. Financing alone will not solve this. It needs to go hand in hand with the right regulations.

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Do you think the EU's targets for the renovation of buildings by 2030 and 2050 are still achievable? What are the steps that need to be taken?

Inger Andresen: I’m beginning to doubt that we will reach the 2030 targets, but there is still time – we just need to work hard. The goals of 2050 should definitely be possible. What needs to happen now, is that each country follows up on their intentions. They need to finalise building renovation plans and build the, stone by stone. There are a lot of good intentions, but little is happening on the ground, also because there are many other things happening in the world that demand attention.

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What is the main message you would give to the EU and global policymakers gathering around the COP31 agenda “Resilient Cities”?

Inger Andresen: My main message would be that creating net-zero energy neighbourhoods is important not only for the climate, but also for the safety and security of our people. These solutions don’t only provide environmental benefits, but also safety and security, because smart use of energy and producing energy locally makes Europe more robust.

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