Photovoltaic expansion at HHU

Eight PV systems are currently planned and due to be installed between 2024 and 2029. The power output of the installations will vary – depending on the size of the system – between 65 kWp and 960 kWp. The first PV system on the HHU campus is set to go into operation in 2024: It will be located on the roof of car park P1 and have a power output of 530 kWp. The electricity it can generate equates to the average consumption of roughly 95 single-family homes. Further systems are planned for buildings 21.44 – 21.49, 23.11/12, 23.21, 25.22/32, 25.33, 26.41 and on the university lake adjacent to the campus (see below).  

An initial estimate forecasts that all the currently planned PV systems will together be able to cover approx. 7% of the campus electricity requirements, with the two largest systems on car park P1 and the university lake together accounting for around 5%. The electricity generated by the other systems will depend on the actual size and implementation of the system.

The green electricity generated here may seem a comparatively small amount, but it must be seen in the context of the high energy consumption on campus. In parallel, efforts will also be intensified to speed up the expansion of renewable energy systems and reduce energy consumption in order to achieve the climate targets.

According to the German Environment Agency, the electricity mix in Germany in 2022 produced emissions of 434 g of CO₂ per generated kilowatt-hour. If you include the upstream chains of the electricity generation processes, this figure rises to 498 g CO₂ equivalent. (Source: CO₂ emissions per kilowatt-hour of electricity rose in 2022 | German Environment Agency – article in German only).

Applied to the estimated output of the PV systems currently planned, this equates to an annual saving of around 700 t of CO₂ excluding upstream chains and 805 t CO₂ equivalent including upstream chains.

HHU generally cannot “just get started” when it comes to building measures. Virtually all the buildings on campus belong to the real estate management company Bau- und Liegenschaftsbetrieb NRW (BLB NRW) rather than the University. This means that construction/renovation measures and the installation of PV systems require prior agreements and contracts between HHU and the BLB NRW. If suitable surfaces are found on older buildings, the presence of hazardous building materials must almost always be expected. In addition, further measures to renew building infrastructure such as the modernisation of electricity distribution stations or the renovation of roofs are often needed first. These are all obstacles to quick implementation. Delays in the planning process, delivery of components or certification of installations can also all slow down the start-up of a PV system.

Experience gained in the current initial PV system projects will be applied in the future to speed up the process. For example, safety and control processes can be defined once for the campus as a whole and then applied when installing further systems in the future. In addition, PV systems are now being considered right from the outset in every construction and renovation project. This means that they will become a natural part of planning and construction processes over the next few years, which will in turn further speed up the expansion.

The installed system will have an output of around 960 kWp, enabling the generation of approx. 840 MWh of electricity per year. This roughly equates to the consumption of 210 four-person, single-family homes. In the German electricity mix in 2022, the generation of one kilowatt-hour of electricity produced an average of 434 g of CO₂ (source: CO₂ emissions per kilowatt-hour of electricity rose in 2022 | German Environment Agency – article in German only). If the expected output of the floating PV system were to be used in this electricity mix, emissions of approx. 365 t CO₂ equivalent would be produced.

According to the procedure “numerical rating of habitat types for impact regulation in NRW” (Numerische Bewertung von Biotoptypen für die Eingriffsregelung in NRW) defined by the NRW State Agency for Nature, Environment and Consumer Protection (Landesamt für Natur, Umwelt- und Verbraucherschutz NRW – LANUV), the floating PV system will cause a slight reduction in habitat quality. Two main measures are planned to compensate for this: Floating reed bed islands will be installed in front of the system to the northeast and southeast, offering areas for various plants and animals, while screening the system from view. Dead wood such as root stumps and pieces of trunk with branches will be sunk to the bottom of the lake in parts of the area around the system. These natural structures will offer areas that can be colonised by microorganisms and provide cover for fish in the otherwise sparse environment of the former gravel pit.

Although the installation costs are usually somewhat higher and the approval process is more extensive, a floating PV system offers several advantages. Floating systems make use of large, mostly unshaded areas. This enables higher outputs in a single project, which in turn speeds up the expansion of renewable energy. They can be realised independently of building/roof renovation measures and, as a result of the cooler environment, generate a higher output than systems on sealed surfaces. They thus represent an important contribution to a successful energy transition alongside installations on buildings and other sealed surfaces.