What challenges do you see in the transition from local energy systems to renewable energies?

Sonja Witkowski: Renewable energy sources are particularly important in the electricity sector. However, we also need to take these sources into account in the supply of heating and domestic hot water, as decarbonization is essential here. However, the electricity and heating sectors are still usually considered separately – a major challenge on the path to the energy transition. Heat and electricity must be seen as a single unit, resulting in economic advantages and robust solutions. We need to detect this, because without energy systems integration, this potential will remain unused.

Carsten Beier: Thereby, we must definitely move towards acceleration and implementation. And this is also in line with the goal set by the Federal Ministry for Economic Affairs and Climate Protection. However, it is important that we don't look at everything in isolation. Then we may have solved something in one place, but created a huge problem in another. We need to develop integrated solutions and think about activities in heat, electricity, mobility and infrastructure all together.

Why hasn't this happened yet?

Sonja Witkowski: In my view, one challenge is that very different players and stakeholders are involved. For example, when I own a building, I usually buy heat and electricity from different suppliers. There is no need, but usually also no incentive to link these things.

Carsten Beier: To make it worse, business economics does not reflect the future problems that arise from sector separation – as overloading the electricity grid. That is why many remain passive. We need to invest now, even if part of the massive economic benefits lie in the future. We need to expand infrastructures now, but this is always slowed down – because investing seems uneconomical for the moment. Sure: Companies must work cost-efficiently. But the challenges facing our society will not arise now, but only in the future. There is no price tag for this, which is why we don’t get started. Another problem is the complexity of local energy systems and the associated groups. It is of course easier to pick out just one thing – even if this means missing out on economic as well as ecological potential.

What needs to happen for something to change?

Carsten Beier: In my opinion, municipal heat planning is a game changer. Several players have to come together and work together – from the local authority and housing company to network operators and municipal utilities, right through to chimney sweeps and environmental associations. And this is guaranteed to reveal many to-dos and joint solutions, but also challenges. Take electricity grids, for example. We have a massive problem here. There are already regions or districts where heat pumps cannot be installed in the way we need them. Distribution grids need to be converted almost everywhere.

How can this development, this cooperation across sectors, be further promoted?

Carsten Beier: In my opinion, this is a task for the legislator, who must ensure stricter framework conditions. There is no other way. It must be clear to the public: We urgently need to get moving if the energy transition is to succeed. And, unfortunately, we must also expect restrictions – from higher energy costs to a change in our heating and mobility habits.

At the same time, I see us scientists having a duty. We have to reduce the complexity that I have already mentioned for the stakeholders. We act as a sparring partner for our customers such as housing associations and owners, municipal utilities and operators of industrial sites with high energy and heating requirements, for example companies in the paper, food, beverage and chemical industries. We develop smart solutions and implement them together – this is precisely our focus in the area of Local Energy Systems.

How can I imagine that?

Sonja Witkowski: We support urban districts and industrial sites in converting their energy supply to renewable energies and low-carbon systems and improving their energy efficiency. We look at the energy generation, storage, distribution and use of electricity, gas, heat, cooling, steam and compressed air and develop integrated concepts for a successful implementation.

This is probably best illustrated by an example: In our project "Future-iQ", new electricity and heat supply concepts are being implemented and tested in existing residential quarters of LEG Immobilien SE – with the aim of reducing CO₂ emissions quickly and in a socially responsible manner. Among other things, a local heating network and photovoltaic systems are being built. We use model studies to shed light on specific questions that arise in the project: For example, should the electricity generated only be used for the heat pump in the energy center or can it also be used for tenant electricity? What should be the minimum amount of tenants who participate in tenant electricity? How many photovoltaic systems do we need if more tenants decide to use the electricity? We answer these questions for different scenarios such as varying fees or electricity prices and thus provide the much-needed basis for decision-making.

In these studies, we also always look at the current system: What happens if we don't change anything? For example, if we stick with the gas boiler and don't use heat pumps or heating networks? This usually results in the worst key performance indicators, which often leads to an "aha" moment for our customers.

Carsten Beier: This model-based approach can basically be thought of as a digital laboratory. Before I, as a company, go into large-scale production with a new process, I have it tested several times in the laboratory or pilot plant to see if it works at all, and then choose the best variant for my parameters. It's the same with our models. We carry out a test in our digital laboratory and see: What is actually happening? In doing so, we rule out the risks and recommend the variant that has both the highest probability and the greatest robustness.

So all in all, it's about showing possibilities...

Carsten Beier: ...and to make them assessable. Our clients should get a feeling for the effects and consequences of individual variants so that they can then make the right investment decision for them and obtain planning security.

And these concepts are individual for each client or are there general recommendations?

Carsten Beier: There are, of course, a few universal basic requirements: we need to electrify, we need heat pumps on a massive scale, we need to refurbish, we need to triple district heating connections, we need hydrogen for large-scale industry and as seasonal storage. These basic requirements must then be broken down to the local level: What are the general conditions at each location? Is it possible to obtain hydrogen? Can wind or solar energy be used? And then, of course, it's about the client's individual data and objectives, which are also considered into our models: What kind of buildings are involved? What are the current electricity and heating requirements? How much space is available for production and storage units? Are there concrete ideas about what is possible and what is not possible?

How do you get this data?

Carsten Beier: Usually via traditional questionnaires. However, depending on the project design, we also use workshops or other exchange formats. In a project in Niederkrüchten, for example, we take into account the needs of the municipality, the wind farm, the business park and the citizens. Everyone then sits around a table – moderated by a representative of the city – and gives feedback. Our task is then to develop solutions that offer advantages for all stakeholders. This is also a form of scientific work.

Is this involvement of stakeholders part of your skills portfolio?

Carsten Beier: Definitely. The combination of technology and stakeholder perspectives is actually one of our unique selling points in the scientific environment.

Sonja Witkowski: The different stakeholders play a role in most of our projects – and at very different levels. For example, we carried out a project with a community of 27 building owners. The neighborhood was built in 2010 with its own combined heat and power plant, heating and electricity grid. The community wanted to know how things could continue when the CHP unit was getting on in years. So we first held a workshop to clarify: What are your expectations? What do you have in mind? We explained what heat pumps actually are and showed them possible solutions – first without any model calculations. We then drew up three/four concepts based on the feedback and used or digital lab to calculate them so that the community could make its investment decision based on specific KPIs.

Once a client has decided on a variant and the corresponding transformation plan is in place, what happens next?

Sonja Witkowski: Once the client has decided on a variant, a planning office is usually commissioned to implement it – for example, to build the production and storage units. If desired, we can also remain involved in this phase and advise on both implementation and operation. This can be useful, for example, if the planning office wishes to make changes to our concept for cost reasons, which would jeopardize the achievement of the initial objectives. Or if framework conditions change and the operating mode or individual components need to be adapted. This support can also be used to demonstrate successes and transfer them to other locations. The economic effects of our scientific work are then particularly great – and we finally get started.