Energy Supply
The University’s energy supply is provided by its own networks for district heating, natural gas, electricity, cooling, compressed air, and water. To this end, RWTH Aachen University operates central facilities to supply its own electricity, heating, and cooling. The mechanization of buildings, which is also necessary for research purposes, also increases the demands on the energy and water supply.
The key procurement, generation and consumption data for the RWTH properties can be found in the data appendix to this Sustainability Report. Further information can also be found in the RWTH energy reports. Further (background) information on the topic of energy can also be found in RWTH’s first Sustainability Report.
RWTH operates a total of three of its own combined heat and power plants (CHP). Today, these generate a total of around a third of the University’s electricity requirements. The University also operates its own central cooling networks. Depending on the location, the waste heat from the CHP units is either used to generate absorption cooling or it is fed directly into the RWTH Aachen University heating network.
Optimize and Modernize
The “Energy 2025” master plan continues to focus primarily on optimizing and modernizing the infrastructure. The decoupling of Aachen University Hospital from RWTH’s heat supply in 2022 made it possible to reduce the network flow temperature in the Melaten heating network. This goes hand in hand with lower energy consumption. Opportunities to integrate large electric heat pumps into supply structures and heating networks are also currently being investigated. The first decentralized heat pumps are already being used or planned in new buildings.
Photovoltaic systems are primarily installed as part of roof renovations and new buildings at RWTH. In the first phase, a total of approx. 1000 kWp of electricity is to be installed on the roof areas to supply the buildings themselves, of which around 300 kWp is already in operation in five systems. One example is the PV system on the roof of the new Plastics Innovation Center (PIC) 4.0, which was last installed in 2023.
RWTH Obtains Green Electricity
Since January 1, 2023, RWTH Aachen University has sourced all of its purchased electricity from renewable sources. In the tendering process in 2022 for the purchase of electricity at RWTH from 2023, corresponding requirements for the purchase of “green electricity” were formulated for the first time, despite the energy crisis that was ongoing at the time. As the term “green electricity” is not protected or defined, it was formulated as follows in the tender for RWTH: “Energy from renewable, non-fossil energy sources: Wind, sun, geothermal energy, energy from the ambient air, hydrothermal energy, ocean energy, hydropower, biomass, landfill gas, sewage gas, and biogas”. It was also included that the quality of the electricity must be verified by means of a certificate – for example a Guarantee of Origin Register (HKNR) or similar.
Development of Energy Consumption
The energy purchased from energy suppliers in the form of natural gas, district heating and electricity at RWTH Aachen University increased by 38% in absolute terms between 2000 and 2022. However, in relation to the simultaneous high increase in floor space (+ 61 %), this corresponds to a decrease of approx. 30 % in terms of the energy consumption index. The heating energy consumption index (weather-adjusted consumption / m² net floor space) at RWTH Aachen University fell by around 40% between 2000 and 2022.
Despite an increase in net floor space and a permanent increase in technology in the research area of the institutes, the area-related specific electricity consumption of RWTH has remained almost constant from 2000 to 2022 (- 3 %) – this is also due to the use of modern building automation and new efficiency technologies. The development of total energy consumption since 2018 is shown in the following chart.
In the Zentrum and Hörn areas, heating requirements are primarily covered by purchased district heating. The district heating is fed into the University’s own network to supply the buildings on Campus Mitte and Campus Hörn, where it covers 70% of the heating energy requirements. The combined heat and power plant in Wüllnerstrasse supplies the remaining 30% as local heating.
In the Melaten area, the heating energy requirements of the University buildings are largely covered by natural gas-fired boilers from the University’s own combined heat and power plant. The coupled district heating accounts for a smaller proportion (20%) of the heating energy supply here. Due to the natural gas crisis, heating oil EL (extra light) was used as fuel in one boiler from fall 2022, so that supply could also be guaranteed during the critical phase of the 2022/2023 heating period. In 2022, the share of natural gas in the heating energy supply was 75% and 5% for heating oil EL.
In addition to the University’s central heating supplies, there are other decentralized feed-in points for district heating and natural gas in individual buildings and building complexes at RWTH Aachen University. These account for around 5% of the total heating energy requirement.
The energy standards of the buildings also influence energy consumption. Due to the large number of old buildings with high heating energy consumption figures, there is a particularly high need for energy-efficient refurbishment of both the building envelope and the systems technology in the Melaten area, for example.
Water Consumption
RWTH’s water consumption has remained almost constant in recent years, most recently falling to 448,645 m³ in 2022 (see data appendix). Around 20% (92,339 m³) is generated as evaporation water – e.g., in the University’s recooling plants. Drinking water is also required for humidifying the air in the air conditioning systems. The quantities of water that evaporate and therefore do not cause waste water are determined using our own water meters. However, higher water consumption is mainly due to the cooling of experimental equipment in the institutes. RWTH endeavors to provide the institutes with the best possible support with regard to the resource-conserving use of drinking water.
Continuing on the Path to Climate Neutrality
In 2021, RWTH committed to becoming climate-neutral by 2030 as part of the Race to Zero. Reducing resource and energy consumption is an important goal in making operations more sustainable.
With this in mind, RWTH signed a declaration of intent for more climate-friendly public buildings in Aachen together with FH Aachen and the city of Aachen in June 2021. With regard to existing buildings, the declaration includes targets for CO2 savings through investments in energy supply infrastructure, plant technology and the building envelope, the implementation of a refurbishment quota, the establishment of an action plan for energy efficiency as part of maintenance, investments in renewable energies and measures to influence user behavior.
RWTH will also need the support of the state of NRW and the Bau- und Liegenschaftsbetrieb NRW as the owner of a large proportion of the buildings and infrastructure in order to successfully achieve these goals.
In order to be able to measure and verifiably reduce consumption, a sound data basis is required. A central “Energy Data Management System,” or EDMS for short, is therefore being developed and implemented in Department 10.0 – Facility Management.