From wind turbines to photovoltaic cells, semiconductors are the microelectronic backbone of the energy transition. These solid materials, with their unique electrical properties, are used to adjust voltage and current from wind turbines to match grid requirements or to directly generate electricity within a solar cell. The best-known semiconductor is probably silicon, with outstanding efficiency at relatively low cost.

In photovoltaic production, quartz sand (silicon dioxide) is melted down and formed into a single crystal. This is a solid in which the atoms are arranged as evenly as possible, explains Markus Riotte, Professor of Semiconductor Physics and Technology. The resulting block of silicon, known as an “ingot,” is then sliced into thin slices (wafers). In the PV Maritim research project, I’m particularly interested in how we can optimally integrate these wafers for their respective applications, Riotte explains. We’re exploring solutions for embedding these thin and sensitive wafers directly into other materials. Integrated lightweight photovoltaics, for example, are suitable for land and marine vehicles, as well as for facade elements.

Maritime transport is an incredibly exciting field for photovoltaics, explains Riotte, Due to the reflections of sunlight on the surface of the water, even vertically mounted photovoltaic modules at sea can achieve significantly better yields than those on land. Naturally, the modules should not weigh down the vessel unnecessarily. The biggest challenge is balancing weight and the durability of the wafers, Riotte says. A wafer is about 200 micrometers thick, approximately twice the diameter of a human hair.

To minimize weight, Riotte is working on integrating the wafers into existing structures—for example, into the superstructure or even the wing sails of a wind-powered cargo ship. Our goal is to integrate the wafers so seamlessly that they resemble a fully painted surface both visually and functionally, Riotte explains. This would allow the ship’s electronics to operate in port without using combustion engines or shore power cables. Ideally, we will one day see cargo ships with wing sails that have photovoltaics fully integrated, Riotte adds. We’ve just launched a research project to make that possible.

Professor Nadine Buczek heads the Laboratory for Energy Materials at TH Lübeck. Together with her colleague, Professor Mark Elbing, an expert in organic chemistry, she is working on the SolarAlgae project.
The project aims to use natural pigments extracted from microalgae to create solar cells. Currently, most solar cells are made from inorganic materials like silicon, but the production of pure silicon is energy-intensive and generates significant waste. With algae-based materials, we are exploring environmentally friendly alternatives, Buczek explains.

First, pigments are extracted from algae and then chemically modified to improve their properties for use in dye-sensitized solar cells. The key here is that we can structure the material at a molecular level to optimize its ability to harness different wavelengths of light, Elbing elaborates.

For us in applied science, it’s not particularly exciting to squeeze out the last percentage of efficiency from solar cells, says Mark Elbing, who has been teaching and conducting research at TH Lübeck for seven years. Of course, from a research perspective, it is interesting to push solar cell performance as far as possible, he adds. But what matters to us at TH Lübeck are broader questions—such as how sustainable and environmentally friendly the production process is, or which manufacturing methods are the most economical.

In their laboratories, Nadine Buczek and Mark Elbing primarily focus on establishing the fundamentals for the production of such solar cells. For implementation, we’ll need industry partners who hopefully recognize the advantages of algae-based solar cells. These benefits range from a more eco-friendly production and easier recycling to material properties like flexibility. These solar cells can be manufactured as thin films and even applied to curved surfaces, Buczek concludes.

Necessary grid expansion also involves varying timelines depending on the voltage level of the grid. While low-voltage grid upgrades can be completed within months to about two years, higher voltage grid expansions require significantly more time.

This makes it all the more important to use the grid efficiently using modern IT systems. Currently, grid operations are managed to present real-time conditions in control rooms for human decision-makers. Especially in the low-voltage grids, where increasing numbers of electric vehicles and heat pumps will be connected in the future, capturing many small-scale data points will be essential. As system complexity continues to grow, automated decision-making becomes both necessary and practical, says Töbermann.

The grid planning expert also finds the cross-sectoral view of energy grids particularly intriguing. In addition to the electrical grid, this includes the hydrogen grid and the points where the two intersect. One of the aims of the large-scale joint research project Norddeutsches Reallabor, in which Töbermann is also involved, is to develop effective solutions for such cross-sector systems and to determine which grid needs to be expanded and to what extent. This approach will allow grids to complement one another, reducing the need for every grid to be expanded to its full capacity.

The Research center for Electromobility, Power Electronics, and Decentralized Energy Supply (EMLE) at TH Lübeck focuses in particular on how to integrate a charging park for electric cars into the grid as intelligently as possible. EVs are significant consumers of energy that are intermittently connected to the grid. “Electromobility is not just a question of energy generation and distribution, but above all about storage, says Clemens Kerssen, EMLE’S spokesperson.

This issue is particularly evident in larger charging parks, for example at rest stops and service stations. When many cars charge simultaneously in a single park, it leads to power peaks on the grid because the charging stations don’t communicate with each other, Kerssen explains. Researchers at EMLE have addressed this challenge and developed a modular, highly scalable charging park system. While ultra-fast charging is critical at highway rest stops, company charging parks might prioritize slower charging, as employees typically leave their cars idle throughout the workday.

The EMLE charging system supports both scenarios and everything in between. The charging stations communicate with one another, and a connected high-performance storage unit absorbs load spikes. This also enables ultra-fast charging. Kerssen illustrates this system in a video demonstration.

On a related note, user-centric design is vital. Ultimately, the system must integrate a transparent and flexible payment solution for consumers. With so many variables, who or what coordinates the entire operation? Artificial intelligence is indispensable here, emphasizes Kerssen.

The building sector accounts for over 30% of final energy consumption in Germany, making it a critical component of the energy transition. In new construction, there are now many ways to reduce energy consumption right from the design stage. Renewable energy sources, such as rooftop photovoltaic systems (PV) or heat pumps that utilize environmental heat, can also be used. What is the challenge then? Reducing energy consumption in existing buildings is a major challenge. The majority of energy consumption in the building sector today comes from existing buildings in cities, neighborhoods, and standalone properties, says Dirk Schwede, Professor of Energy and Building Engineering in the Department of Architecture and Civil Engineering at TH Lübeck.

What are the solutions? Key to the energy transition are, first, the energy retrofit of buildings to reduce final energy consumption, and second, the climate-neutral supply of energy in the form of electricity and heat from renewable sources. It’s essential to develop balanced and economically viable renovation strategies for both individual buildings and across neighborhoods that can be practically implemented under local technical and socio-economic conditions. The current funding landscape for energy-efficient renovations also plays a critical role, Schwede notes. Organizational questions are equally important: How do you renovate occupied buildings? Common technical questions include: Is the heating system suitable for a heat pump? or Will there be a climate-neutral district heating supply in the future?

Professor Dirk Schwede both researches and teaches these approaches at TH Lübeck. He is an internationally sought-after expert on energy-efficient, climate-friendly, and sustainable buildings. In this role, he connects with networks locally and globally. One local example is the Community of Practice: In the Community of Practice (CoP), we bring together stakeholders working on the energy transition in the building sector from the Lübeck region to discuss relevant topics and foster exchange between different groups, Schwede explains.

It’s not just new constructions that are relevant: many existing buildings will not undergo any fundamental renovations by the target year for climate neutrality, but must still make their contribution. This contribution will not come in the form of energy-efficient renovation, but rather through building operations optimization and user engagement. To unlock this potential, an interdisciplinary research team at TH Lübeck launched a project called Digital Infrastructure for Sustainable Building Operations (DING) heißt es.

As part of this project, typical existing buildings used for teaching, research, and administration on the TH Lübeck campus are being closely examined. The goal is to collect and share data that enables researchers to study how building usage impacts energy consumption and supply. Based on this data, the team develops further strategies to reduce energy consumption and increase the use of renewable energy. The project involves collaboration between four subject areas from the departments of Architecture and Civil Engineering, Electrical Engineering and Computer Science, and Applied Natural Sciences.

Investments have been made in modern stationary and mobile measurement technologies, including sensors for indoor air, windows, heating, and lighting, as well as meters for heat and electricity consumption. Sensors to monitor building usage and weather conditions have also been implemented. In addition, digital models of the buildings have been created that contain all the information needed for simulations to develop innovative operational strategies. DING allows us to carry out comprehensive research projects focused on optimizing building operations and engaging users while testing innovative approaches and methods in a real-world laboratory, explains project leader Professor Sebastian Fiedler, highlighting the value and sustainability of the project.

The data collected in the DING project can be used to feed building simulations. Often, it’s not immediately clear which energy measure is most promising for a given building, because building design and building systems must work in harmony.

Christian Blatt, Professor of Building Simulation and Optimization, explains: The beauty of a building simulation is that you can visualize what you are doing. You can compare many different scenarios and identify the best solution.For instance, simulations can display different thermal layers inside the building, indicate the temperature at varying heights, and show how air circulates throughout the building. This makes it possible to determine the ideal number, height, and size of windows, the placement of ventilation systems, and which technical systems would be most suitable.

While new construction typically begins with well-defined parameters, work on existing buildings begins with gathering the necessary information: Are the original blueprints still accurate? How thick are the walls? Which materials were used? What is typical for buildings of that era and region? In some cases, measurements have to be taken on site. The goal is a detailed room database, that serves as basis for the simulation. With that data, you can reconstruct the building from the ground up, says Blatt. Then you can begin to simulate and optimize systems, like heating. A frequent concern is to avoid overheating and improve summer thermal protection. Large glass surfaces are particularly tricky. You have to consider how far you can go with passive ventilation concepts and shading, or whether you need air conditioning - otherwise you can quickly end up with 50°C (122°F) indoors, Blatt notes.

The building sector is a major driver of sustainable transformation not only in Germany but worldwide. Globally, it contributes substantially to greenhouse gas emissions, resource consumption in the form of building materials, land use, and waste generation. At the same time, the built environment provides the framework for comfortable, high-quality living.

Professor Dirk Schwede, who has previously worked as a researcher and consulting engineer in Australia, Asia, and the Middle East, is involved in various projects focusing on sustainable construction abroad. In the BMBF-funded project Climate-Adapted Material Research for the Socioeconomic Context in Vietnam (CAMaRSEC) a large consortium of scientists from Germany and Vietnam investigated the use of sustainable building materials for tropical climates in Vietnam. In another BMBF-funded project, Resource-Efficient Construction with Sustainable Building Materials (ReBuMat) interdisciplinary networking among researchers and practitioners to promote the use of sustainable materials.

Professor Schwede’s work in the sustainable development and transformation of the construction and building sector in other countries is part of technical development cooperation projects. Key topics include energy-efficient heating, cooling, and ventilation of buildings, resource-efficient construction, and life cycle assessment of buildings. These projects also focus on developing evaluation and financing instruments for sustainable buildings and neighborhoods, tailored to countries at different stages of development in their construction industries.

Our society will continue to consume electricity, which is why faculty and students at TH Lübeck are exploring smart ways to generate it. Whether through lightweight solutions for maritime applications, solar algae, or thermoelectric generators, innovative approaches are at the forefront. The energy produced must then be distributed intelligently and efficiently. Researchers at TH Lübeck are working on that as well, developing technical systems to optimize grid utilization,whether at the level of large-scale grid planning or improving decentralized networks, such as those for EV charging parks.

We also focus on improving the thermal energy efficiency of buildings. This involves taking measurements, running simulations, and analyzing materials and their production under different conditions. Most importantly, we are training the skilled professionals who will lead the energy transition in every sector. It’s no exaggeration to say that TH Lübeck excels at optimizing both efficiency and consistency.

What we can’t solve with technology alone is sufficiency—learning to live with enough. That responsibility lies with all of us as a society.