Ten years of the DLR In­sti­tute of So­lar Re­search

An abundance of energy, available almost anywhere in the world and with no climate-unfriendly emissions. It might sound too good to be true, but the Sun could help us fulfil these ambitions. However, first humankind must develop technologies that can harness this potential. Bernhard Hoffschmidt and Robert Pitz-Paal have jointly led the DLR-Institute of Solar Research for 10 years. In that time, they have built up a motivated team dedicated to this task. Since the establishment of the Institute, the questions surrounding the nature of future energy supplies have gained in importance. In this interview, they discuss the past, present and future of their research.

Where did solar research at DLR begin?

Pitz-Paal: As early as the 1970s, DLR researchers at the sites in Stuttgart and Cologne were conducting research into how solar energy could be used to generate electrical power. In the late 1970s, the International Energy Agency entrusted DLR with managing the development and construction of a first experimental facility for solar thermal power generation. The Plataforma Solar de Almería (PSA) in southern Spain was established with participation of nine countries. Researchers from DLR and the Spanish research centre CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas) have been working there together since 1984.

Hoffschmidt: In 2002, DLR’s solar research activities were consolidated to form a department within the Institute of Engineering Thermodynamics. The commercial spread of solar thermal technologies began to pick up speed in Europe in 2007, which provided an opportunity to turn the department into its own institute. This was followed by an exciting time in which we founded a new DLR site here in Jülich and converted a commercial demonstration power plant into a large scale test facility.

Has the Institute’s portfolio changed since its establishment?

Pitz-Paal: In the early days, we tended to focus more on parabolic trough technology. However, we realised that although tower tech nology was at an earlier stage of technological readiness, its potential cost-effectiveness was likely greater. As a result, the focus of our research has shifted more towards tower power plants. Just last year, we opened a new facility, the Multifocus Tower in Jülich, which has three experimental levels in which new technologies for concentrated solar radiation can be tested.

Hoffschmidt: In addition, a new institute was founded from one of our departments – Future Fuels. Everything here revolves around climate-neutral fuels.

Management of the Institute
Robert Pitz-Paal (left) and Bernhard Hoffschmidt are the joint directors of the DLR Institute of Solar Research.

How has the growing importance of the climate and sustainability in public discussion affected your work?

Hoffschmidt: Overall, it has been very positive. At the political level, for example, our topics were included in the German Federal Govern ment’s 7th Energy Research Programme and the EU’s Strategic Energy Technology Plan as early as 2018.

Pitz-Paal: There has also been a marked increase in general interest. We are receiving ever more enquiries from students who want to work at our Institute. We also get media enquiries; even educational chil dren’s television programmes are showing an interest.

You work closely with the business community and have launched various spin-offs as independent companies. How do you encourage such developments?

Hoffschmidt: We are very proud that we have managed to bring many of our findings into practical application. Solar collectors or measurement processes that we helped to develop are now being used in 90 percent of the relevant systems installed worldwide. The initiative usually comes from the employees themselves, as they are keen to commercialise their research topics and ideas. Of course, the Institute has to provide fertile soil for this type of endeavour. In our experience, successful spin-offs inspire others to do the same.

Energy will be an increasingly important topic in the coming decades. How will the Institute of Solar Research respond to this?

Pitz-Paal: There are a number of major challenges in terms of addressing climate change in time and with technologies that can be implemented quickly. In addition to the expansion of solar thermal power plants for generating electricity, the provision of industrial process heat is going to become increasingly important. The combination of photovoltaics and solar thermal technology will also gain prominence. Together, these two types of technology make an essential contribution towards a reliable and cost-effective energy supply system. Finally, we will also transfer our expertise in the field of non contact measurement technologies to other areas of application, such as building technology and photovoltaics.

This article was published in DLRmagazine 168

Light becomes electricity
Since its establishment in 2011, the Institute of Solar Research has been researching and developing Concentrated Solar Power (CSP) systems for solar thermal power plants that convert solar energy into heat, electricity and fuels. This includes parabolic trough technology, Fresnel collectors and solar tower systems. With parabolic trough technology, a concave mirror concentrates solar radiation. At the focal point of the mirror trough is a tube through which a liquid flows, which is heated by the concentrated radiation and evaporates. The steam is then used to drive turbines. Fresnel collectors are similar to parabolic trough collectors but have a flat, sanded surface. In a solar tower power plant, several hundred steer able mirrors direct sunlight towards a receiver on the top of the tower. This can generate temperatures of up to 1000 degrees Celsius, which are used to vaporise water.

Other research topics addressed by the Institute include the development of new heat transfer mediums and the measure ment and evaluation of components for solar thermal power plants. The scientists are also conducting research into related areas. The sensor technologies developed at the Institute are used, for example, to determine the energy-related renovation requirements for buildings, while the Energy Meteorology group develops systems to increase the efficiency of solar power plants and photovoltaic systems. The aim of research conducted at the Institute is to increase the efficiency of solar energy and heat generation and thus lower the costs of production. The Institute operates various large-scale facilities at its sites in Cologne, Jülich, Stuttgart and Almería (Spain), allowing it to address the entire research chain from the laboratory through to industrial applications.


Michel Winand

Corporate Communications Aachen, Bonn, Cologne, Jülich, Rheinbach and Sankt Augustin
German Aerospace Center (DLR)
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