Photovoltaics

Renewable energy sources are expected to account for 40 to 45 percent of the electricity consumed in Germany by 2025, as stipulated in the Renewable Energy Sources Act (EEG). Photovoltaics (PV) play a leading role in this. Especially in urban environments, the use of wind power is limited, whereas PV can shine here due to its excellent integrability. Therefore, PV is the main contributor of renewable energy in the LLEC project. All PV systems on campus are integrated into a virtual LLEC power grid. Thus, on balance, the electrical energy generated by the PV systems can either be used directly, transformed into hydrogen by means of electrolysis and stored in gaseous or liquid carrier form, or temporarily stored in the battery storage systems. The ICT platform takes over the control.

PV Ground-Mounted Systems

In the LLEC, we are currently using fallow open spaces on a former reactor site within our campus ("Jülicher Entsorgungsgesellschaft für Nuklearanlagen mbH") to construct larger PV power plants with a total capacity of 1.1 MWp.

PV on and at Buildings

In addition, PV systems were (and are) installed on suitable existing buildings and new buildings. This is done not only in the form of roof systems, but also in more innovative solutions, such as building-integrated facade PV, PV in skylights of stairwells or as a PV pergola on the roof terrace of the JuLab student laboratory. At the end of the first project phase, a total of 1.5 MW of solar capacity will thus be installed in various PV systems on the Jülich campus. Most of the PV systems have already been realized.

Dual land use

But this is not all: With increasing expansion of renewable energies, competition for land is also increasing. Dual land use concepts will become increasingly important in the future. In addition to façade-integrated PV, at LLEC, we are also investigating the synergy between walkways and PV in a short piece of PV walkway. Here, we are particularly interested in the performance and aging of the PV sidewalk modules. This is because sidewalk modules are exposed to high mechanical loads. Wetness and pollution can also have a major impact on the lifetime of the PV modules.

Agri-PV systems represent another example of dual land use. In such a facility, certain crops can be profitably grown under PV panels and are protected from sun, too much precipitation or severe weather. In cooperation with the Institute of Bio- and Geosciences (IBG-2, Plant Sciences) and the Institute of Energy and Climate Research (IEK-5, Photovoltaics), an Agri-PV demonstrator plant of about 70 kWp will be built on campus.

Future PV applications

In the further course of the project, further innovative PV concepts are to be implemented. This can take the form of small-scale demonstration systems, or larger systems to sustainably increase PV capacities on campus. For example, a small floating PV system on the campus lake is currently being considered, as are self-sufficient PV parking lot canopies in conjunction with charging stations for e-vehicles.

PV-Research topics in the LLEC

From a research perspective, we are primarily concerned with the performance of the PV systems, but the reliability, aging and service life of the various systems are also a focus of our research work. For this purpose, we are currently setting up a single-module characteristic curve measurement system on the new office building 2.6. This is co-financed by the federal state of North Rhine-Westphalia as part of the PV Reliability Project. In this performance and reliability laboratory, modules from the LLEC PV demonstrators are examined to determine degradation models and performance predictions. Shadowing tests and advanced tests such as PID (Potential Induced Degradation) can then also be performed there. An important topic in this context is automatable imaging methods for evaluating module damage (defects) and effects on module performance or scaled up to system performance. For this purpose, we also use AI (artificial intelligence) methods and leverage the expertise of our colleagues at the Jülich Supercomputing Centre (JSC). The new measurement procedures and analysis methods can then be tested on the PV systems at LLEC.