Institute of Solar Research. Concentrating Solar Systems for Power, Heat and Fuel Generation

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1 Institute of Solar Research Concentrating Solar Systems for Power, Heat and Fuel Generation

2 New materials and technologies for solar power generation are tested at the DLR solar tower facility in Jülich (see front page). Frequent measurements are performed in this test facility to monitor the mirrors' reflectivity. Academic and industrial customers use the solar furnace at DLR's Cologne site for experiments with highly concentrated solar radiation. Institute of Solar Research The DLR Institute of Solar Research is the largest research entity in Germany investigating and developing concentrating solar technologies to provide heat, electricity and fuel. The German Aerospace Center (DLR) has been conducting research in this field for more than 30 years and has in June 2011 bundled its activities in the newly founded Institute of Solar Research. The employees of the Institute work at DLR's headquarters in Cologne, at the DLR sites in Jülich and Stuttgart, as well as in the biggest European test center for concentrating solar technologies, the Plataforma solar de Almería (PSA) operated by DLR's Spanish research partner CIEMAT. In 2011 DLR took ownership of the solar tower power plant in Jülich to carry out industrial-scale research. The federal state of North Rhine-Westphalia has provided substantial funding towards the extension of the experimental solar facility Solarturm Jülich and its conversion into a large-scale scientific research facility operated by DLR. The institute s extensive scientific knowledge and outstanding research facilities qualify it as a world leading research institution and center of expertise in the field of concentrated solar power systems. Global networking takes place mainly through the SolarPACES implementing agreement (Solar Power and Chemical Energy Systems) of the International Energy Agency (IEA). In this network, DLR has taken on numerous coordinating functions. In Europe, DLR is affiliated to the European Renewable Energies Research Centres Agency (EUREC), the industry association European Solar Thermal Electricity Association (ESTELA) as well as the European Energy Research Alliance (EERA). In 2004, DLR founded with partners from France, Spain, and Switzerland SOLLAB, the Alliance of European Laboratories for Research and Technology on Solar Concentrating Systems. Nationally, DLR is affiliated to the "Renewable Energy Research Association (FVEE)", whose members research and develop technology for the utilization of renewable energy and its integration in energy systems, energy efficiency improvement, and energy storage. Twice in succession, in 2006 and in 2009, the team was awarded the title "DLR Center of Excellence" for its scientific, technological and economic performance. Within DLR, the Institute of Solar Research closely cooperates with the Institute of Technical Thermodynamics, which works on thermal energy storage systems and studies the impact of a wider introduction of renewable energy by way of systems analysis. Further partnerships exist with the DLR Institute of Materials Research in the field of ceramic high temperature materials, as well as with the DLR Institute of Combustion Technology in the area of the solar gas turbine systems. Research Goals The short term objective of the Institute of Solar Research is to deliver R&D services to German and European industry partners. With state-of-the-art equipment and leading experts in the field of concentrated solar power the Institute supports manufacturers and system developers to reach high technical quality standards and to ensure optimum operation of the components installed in solar thermal power plants. The medium term goal is to reduce production cost, as low cost is the main requirement to achieve a wider market penetration. The aim is to bring down solar power production costs form about cents today to below 10 cents per kwh depending on the site. In the long term, solar thermal systems should also serve to provide a costeffective way to produce solar fuels (such as hydrogen). Cooperation with Industry As an important element in achieving its research objectives and enhancing its technology competence and leadership, the Institute of Solar Research is actively engaged in networking with industry partners, working in a number of collaborative projects, e.g. funded in part by German Federal Ministries or the European Commission. The Institute also operates as a research and development service provider and consultant in industry projects. Cooperating at various levels permits a direct technology transfer to the companies as well as a professional exchange of knowledge and experience between research and industry.

3 The sun simulator test bench at the QUARZ Center is used to evaluate the optical efficiency of parabolic trough receivers. A solar furnace uses concentrated solar radiation to produce renewable hydrogen via a mixed oxide reaction. Solar receiver-reactors like this one for sulfuric acid splitting open up a wide spectrum of energy relevant chemical processes. The activities of the Institute of Solar Research are grouped into five departments. Point Focus Systems R&D activities mainly revolve around solar tower plants. The intention is to reduce the cost of electricity generation, aiming to make solar power available at competitive prices in the mid-term. Main Topics: Design, analysis and optimization of concentrators and heliostat fields Development of efficient receiver technologies for high temperatures and solar fluxes Design and optimization of future solar tower plants on the system level Development of improved control technologies for heliostat fields, receivers and power plants Development of specific simulation tools Line Focus Systems This technology has been commercially applied in solar thermal power plants for decades. Research activities concentrate on innovative improvements of processes and components, and the exploitation of new applications, e.g. the use of industrial process heat, or co-generation of heat and power. Optimization of the direct steam generation in terms of process technology, control and live steam parameters Investigation of alternative heat transfer fluids for increased process temperature and conversion efficiency Exploitation of cost reduction potentials by developing and testing efficient components with reduced material consumption and low labor intensity Demonstration of new technologies at a relevant scale Consulting services to support technology transfer in commercial project development and demonstration activities. Qualification The aim of this part of our work is the development and provision of appropriate measurement methods and devices to be able to measure and assess the quality of components and systems used in solar thermal power plants. Another important research area is the investigation of degradation mechanisms and the verification of component durability by using accelerated aging methods. Measurement and evaluation of collector component and system quality Development of new measurement methods and acceptance procedures Studying the influence of meteorological parameters on solar thermal power plants Development of global standards for component evaluation Tests to evaluate the durability of materials used in the desert All research is carried out using our own instruments in the laboratories and test facilities at DLR's QUARZ-Center in Cologne and at the Plataforma Solar de Almería (PSA). Solar Chemical Engineering The objective of this research is to develop energy relevant chemical processes powered by solar radiation. Production or upgrading of fuels, especially hydrogen Solar water detoxification and desalination as well as the solar powered production of chemicals Development and scale-up of reactors and processes Systems optimization and economic process evaluation A new solar water treatment technology, developed by DLR is distributed by the DLR spin-off company SOWΛRLΛ GmbH, which has been founded jointly with one of DLR's industry partners, Hirschmann Laborgeräte GmbH & Co. KG. At the CeraStorE competence center, the solar chemical engineering department, jointly with the DLR Institutes of Technical Thermodynamics and Materials Research, explores the use of innovative ceramic materials in energy systems. The main topics are reactive redox materials for solar fuel production and new high temperature and corrosion resistant materials for solar receiver-reactors. Facilities and Solar Materials This Department provides state-of-the-art services to facilities using concentrating solar technologies up to the megawatt scale, and offers essential guidance concerning the selection of materials for applications derived from solar research. Deployment and operation of pilot plants for experiments with highly concentrated solar radiation for academic and industrial users Supporting users during preparation, implementation and evaluation of their experiments Development of specialized instrumentation and test infrastructure Determination of thermo-physical properties of functional high temperature materials Description of heat and mass transfer processes in porous materials

4 At the Plataforma Solar de Almería researchers of the Institute of Solar Research test various technologies under real conditions. The high flux solar furnace and an electrically powered high flux solar simulator in Cologne allow tests with irradiances up to several MW/m 2. Germany's solar thermal test power plant is located in Jülich. Its research platform can also be used for experiments with highly concentrated solar radiation. Preparations are underway to build a number of additional CSP testing facilities on the open premises of the Jülich plant. Research for Climate Protection The high global climate protection potential of solar thermal power plants is likely to create large markets in particular for emerging industrial countries of the sun belt of the Earth. Climate protection and the prospect of future export opportunities are therefore the main reason for German companies and DLR to become intensively involved in the development of concentrating solar systems. To achieve the climate protection targets and security of supply in Germany in the long term, imported solar thermal electricity can become an important factor in establishing a renewable energy supply system. DESERTEC DESERTEC relies on baseload-capable and well adjustable solar thermal power plants in the sun belt of the Earth to create climate-friendly power for Europe, the Middle East and North Africa and to compensate for the fluctuating energy provided by photovoltaic and wind power plants. The DESERTEC concept is based on the MED- CSP, TRANS-CSP and AQUA-CSP studies conducted by the DLR Institute of Technical Thermodynamics, which demonstrated the potential of renewable energy for the sustainable production of electricity and drinking water in said regions. In the coming years DLR will continue in its efforts to support industry and government in finetuning the DESERTEC concept, expand its partnerships with countries in the region and promote the import of adjustable solar energy as an important part of the energy revolution.

5 Parabolic trough test facility for direct steam generation at the PSA. Technologies Concentrating solar systems work like very large lenses: they concentrate solar radiation to generate heat. At high temperature levels of up to 3000 C solar thermal energy can be used to generate electricity, either for immediate use in technical processes or for the production of fuels. Because only the direct sunlight can be focused, it makes sense to implement this technology especially in the sunny regions of the Earth. In theory, 1% of the area of the Sahara desert would suffice to cover the electricity consumption of the world by operating solar thermal power plants. A special advantage of solar thermal power plants is that they can compensate for variations in radiation by heat storage or additional combustion, which enables them to provide electricity on demand. Thus, at very low fuel expenses, solar thermal power plants can achieve the same high security of supply as fossil fuel power plants. Their commercialization and market launch has begun. New power plants of this kind are currently under construction in several countries, especially in Spain and the United States. Industrial prototype linear fresnel collector under test at the PSA. To concentrate solar radiation, various technologies are currently being used and further developed. Parabolic trough collectors track the sun in a single axis. The direct solar radiation is concentrated onto an absorber tube in the focal line. A thermal oil circulates inside the tube as a heat transfer medium. The fluid is heated up to its limit of just under 400 C and then used for steam generation in a conventional power plant. The use of this technology dates back as far as the late 1980s, when nine Californian solar thermal power plants with a total electrical capacity of 354 MW were put into operation. Since 2006, new commercial parabolic trough power plants have been built in many sun-rich countries around the world starting in Spain and the United States - meanwhile growing by more than 1000 MW per year. A similar principle is that of linear Fresnel collectors with narrow, shallower reflector elements and a stationary absorber. A first commercial 30 MW power plant of this type was commissioned in Spain early in To increase power generation efficiency, the next generation of parabolic trough and linear Fresnel collectors are designed to reach steam temperatures of around 500 C through the direct evaporation of water and subsequent overheating in the absorber tube, or through the use of molten salt mixtures as a heat carrier medium. Innovative storage models for solar thermal power stations are being developed in close cooperation at the DLR Institute of Technical Thermodynamics. In a solar tower power plant, mirrors of up to 200 m2 in size (so-called heliostates) track the sun in two axes, concentrating the direct radiation by a factor of 500 to 1000 at the top of a central tower. There, a heat transfer fluid is heated typically to a temperature between 250 C and 1000 C, and sometimes even beyond. To study and qualify various heat transfer fluids for suitability, trials were run in several tower power stations. PS10, the world's first commercial solar tower power plant with an electrical output of 10 MW has been in operation since 2007 in southern Spain. In 2009, an additional 20 MW power station, PS20, was built in its neighborhood. In 2011, a 15 MW solar tower was built near the city of Cordoba. It uses molten salt as heat transfer fluid and storage medium, which makes it possible to operate the plant round the clock since it has a 15-h thermal energy storage capacity. Currently, a number of commercial solar tower power plants with an even higher power output are under construction in the United States and will shortly be commissioned. Thermal storage provides solar thermal power generation with additional flexibility. About half of today's parabolic trough power plants in Spain are operated in the 50 MW range and use a molten salt storage system that permits up to seven hours full load operation without sunshine. For the various solar power technologies with different temperatures and heat transfer media, innovative storage concepts and media are being developed and tested in pilot plants.

6 DLR at a glance DLR is Germany s national research centre for aeronautics and space. Its extensive research and development work in Aeronautics, Space, Energy, Transport and Security is integrated into national and international cooperative ventures. As Germany s space agency, DLR has been given responsibility for the forward planning and the implementation of the German space programme by the German federal government as well as for the international representation of German interests. Furthermore, Germany s largest project management agency is also part of DLR. Approximately 7000 people are employed at 16 locations in Germany: Cologne (headquarters), Augsburg, Berlin, Bonn, Braunschweig, Bremen, Goettingen, Hamburg, Juelich, Lampoldshausen, Neustrelitz, Oberpfaffenhofen, Stade, Stuttgart, Trauen, and Weilheim. DLR also operates offices in Brussels, Paris, and Washington D.C. DLR s mission comprises the exploration of Earth and the Solar System, research for protecting the environment, for environmentfriendly technologies, and for promoting mobility, communication, and security. DLR s research portfolio ranges from basic research to the development of tomorrow s products. In that way DLR contributes the scientific and technical know-how that it has gained to enhancing Germany s industrial and technological reputation. DLR operates large-scale research facilities for DLR s own projects and as a service provider for its clients and partners. It also promotes the next generation of scientists, provides competent advisory services to government, and is a driving force in the local regions of its field centres. Institute of Solar Research Directors: Prof. Dr.-Ing. Robert Pitz-Paal Prof. Dr.-Ing. Bernhard Hoffschmidt SF-0912-KP-B-en-001 Linder Höhe Köln Telefon: Telefax: solarforschung@dlr.de Internet: