About 60 kilometres west of Cologne on its Juelich site, DLR operates an experimental solar thermal power plant.
The Juelich solar tower was developed and built between 2005 and 2010 by a consortium of research institutions, industry and local energy providers with significant scientific input from DLR. It is part of DLR’s “Solar Thermal Testing and Demonstration Power Plant“ project. After its successful completion, the solar tower was taken over from the local energy provider, Stadtwerke Juelich GmbH, on July 1, 2011.
Covering an area of about ten hectares, 2153 controlled mirrors, or heliostats, re-direct the incident solar radiation to the top of a 60 metre high solar tower where the focused sunlight is collected by a 22 m² solar receiver and converted into heat. The receiver consists of a porous ceramic material that is constantly permeated by ambient air. In the process the air reaches a temperature of up to 700 degrees Celsius, and is then used to generate steam that, in turn, powers a turbine generator to produce electricity.
The plant‘s rated output is 1.5 MW. The power is fed into the medium-voltage public grid. A high temperature heat storage unit serves as a buffer to de-couple the energy requirement of the process from any temporary fluctuations of incoming solar radiation, thus ensuring a significantly steadier feed to the grid.
Funded by the state of North-Rhine Westphalia, partners from industry and research institutions are developing additional equipment and test fields to upgrade the Juelich experimental solar power plant into a complete solar research centre. In a variety of research projects, new components and processes are being tested which could help make solar power plants more cost and energy efficient. Other investigations focus on methods to produce solar fuels, and to use solar thermal installations for industrial processes (such as sea water desalination).
Primary areas of research are to study newly designed mirror systems for re-directing and concentrating sunlight, solar absorbers, and the practical application of energy storage systems. Further research looks at theoretical and computer-assisted analysis and engineering developments in the field of flow mechanics and heat transfer. For these purposes, the site has been given a number of additional office, workshop and storage facilities in the immediate vicinity of the solar tower.
In this context, the experimental solar thermal plant in Juelich serves as a pilot and reference model for future commercial plants to be installed in suitable locations, such as southern Europe, northern Africa and the Arab Peninsula. A similar power plant that works on the same principle, but hybridised, is currently in its project development stage and will be built in Algeria by one of the Juelich consortium partners, Kraftanlagen München, who will act as prime contractor. This is how the technology, originally developed in Germany, will get a chance to become operational in one of the sunniest regions of the Earth, where there is vast solar energy potential. The technology will also play a major part in the DESERTEC power generating initiative.
In early 2013, permission was granted by the local land development authority to install additional testing equipment on the Juelich premises. Following a necessary extension of the basic infrastructure, the construction and commissioning of an innovative high-temperature thermal storage unit for use with the solar tower systems is to commence in mid-2014.