A record year for our living lab for building-integrated PV
© BAIP/HZB
In 2025, our solar facade in Berlin-Adlershof generated more electricity than in any of the previous four years of operation.
With about 32 MWh, the solar facade of our BIPV living laboratory produced enough electricity to power more than 12 average four-person households. Thanks to the energy-intensive research landscape at the Helmholtz-Zentrum Berlin, we can also consume all of the electricity generated on site at any time.
Even after five years of operation, our building-integrated solar modules show no measurable degradation. Differences in annual energy yield can so far be attributed exclusively to weather-related fluctuations. According to the German Weather Service, the duration of sunshine in 2025 was around 1,900 hours nationwide. In addition, the year was comparatively low in precipitation, which, together with the high duration of sunshine, explains the high solar yield.
However, we were particularly surprised by December: exceptionally good PV weather led to yields more than twice as high as in the previous year! Especially in spring, autumn and winter, the sun is more favourable for the solar facade, so we regularly observe higher yield peaks than in the summer months.
We are excited to see how this year will turn out.
- BESSY II: How intrinsic oxygen shortens the lifespan of solid-state batteriesAlthough solid-state batteries (SSBs) demonstrate high performance and are intrinsically safe, their capacity currently declines rapidly. A team from the TU Wien, Humboldt-University Berlin and HZB has now analysed a TiS₂|Li₃YCl₆ solid-state half-cell in operando at BESSY II using a special sample environment that allows for non-destructive investigation under real operating conditions. Data obtained by combination of soft and hard X-ray photoelectron spectroscopy (XPS and HAXPES) revealed a new degradation mechanism that had not previously been identified in solid-state batteries. They have gained some surprising insights, particularly regarding the harmful role played by intrinsic oxygen. This study provides valuable information for improving design and handling of such batteries.
- Spintronics at BESSY II: Real-time analysis of magnetic bilayer systemsSpintronic devices enable data processing with significantly lower energy consumption. They are based on the interaction between ferromagnetic and antiferromagnetic layers. Now, a team from Freie Universität Berlin, HZB and Uppsala University has succeeded in tracking, for each layer separately, how the magnetic order changes after a short laser pulse has excited the system. They were also able to identify the main cause of the loss of antiferromagnetic order in the oxide layer: the excitation is transported from the hot electrons in the ferromagnetic metal to the spins in the antiferromagnet.
- Electrocatalysts: New model for charge separation at the solid-liquid interfaceHydrogen is at the heart of the transition to carbon neutrality, as both an energy carrier and a reagent for green chemistry. However, large-scale production of hydrogen via electrolysis, as well as the production of many other chemical products, requires significantly cheaper and more efficient catalysts. A precise understanding of the electrochemical processes that take place at the interface between the solid catalyst and the liquid medium is highly useful for developing better electrocatalysts. In the journal Nature Communications, an European team has now presented a powerful model that determines charge separation at the interface, the formation of the electric double layer and local electric potential variations, and the resulting influence on the catalytic activity.