Testsing and development of components and systems for commercial solar thermal power plants. The aim is to make solar thermal power plants more efficient. They also test processes for solar water splitting, the production of solar fuels and the use of solar heat in industrial processes.
More than 2,000 movable mirrors (heliostats) cover an area of around ten hectares in front of Jülich's two solar towers. They catch the sunlight, concentrate it and direct it onto the two solar towers.
In the solar tower power plant, a volumetric receiver at the top of the tower absorbs the concentrated sunlight and uses it to heat the surrounding air to up to 700 degrees Celsius. A steam generator inside the tower uses this to heat water into steam, which drives a turbine that produces electricity via a generator.
https://www.dlr.de/en/research-and-transfer/research-infrastructure/solar-towers-juelich
Photovoltaic solar panels turn light directly into electricity. This thing bounces light to a place where it can be turned into heat. The heat boils water, and the steam turns a turbine. The spinning motion is converted into electricity.
Steam power is a lot older than photovoltaic cells. Nearly every other form of power generation is basically just spinning a turbine. Nuclear, coal, and geothermal heat up steam. Hydro and wind get nature to spin the turbine. With steam power, all your problems with efficiency are mechanical. How do you reduce friction in the bearings? How do you get more power out of the steam? Whereas developing more efficient PV cells requires a deep understanding of subatomic physics. On the other hand, it's difficult to think your way out of physical limits on steam power, like where does the waste heat go? The future of PV probably still has surprises left for us.
Also it sounds like the energy can be stored and used even when there is no sun! Lastly, they also mention experiments with splitting water into fluel, so i expect this is just splitting water into hydrogen right?