Promoting a Sustainable Organization

RWTH Aachen University is a public institution, which means that the operation of RWTH’s infrastructure and all organizational aspects are subject to the regulations of the State of North Rhine-Westphalia. These legal framework conditions set out the requirements for activities such as procurement, the awarding of service contracts, building and energy management, waste management, and the handling of chemicals and hazardous substances. State-specific regulations also have an impact on the autonomy of universities, such as those stipulated by the Building and Real Estate Management Agency (BLB) for North Rhine-Westphalia, which owns most of the University’s buildings and which requires close collaboration in real estate and construction management, including the necessary operational processes.

The University would like to ensure that within these conditions not only sustainability aspects are implemented in RWTH’s operations, but also that these operations are structured to facilitate sustainability as a whole. University members have therefore committed to the following in the joint Sustainability Mission Statement:

We consider sustainability to be an integral part of our actions, and to this end we use our resources responsibly and efficiently in the construction, refurbishment, and management of our buildings and infrastructure, as well as in procurement and mobility issues, and in all other areas of our work. It is fundamental for us that our outdoor areas are used and maintained in an environmentally friendly way as is the planning of our use of land. Through coordinated joint action, we want to reduce the consumption of resources and energy and – where possible – rely on fair and sustainable alternatives. This is what we – the students, instructors, researchers, and technical and administrative employees of RWTH – aim to work on together, as a university. In order to foster this process within the University, we will continuously expand our information and training offerings so that we can become ever more qualified and competent when it comes to acting in a sustainable manner.

RWTH Sustainability Mission Statement

The following section provides insights into the strategies, development of the various areas of work, and concrete measures and projects that seek to ensure the sustainable development of the University’s operations. The topics of Buildings and Spaces, Energy Supply, Procurement, Waste Balance & Disposal, Mobility and Greenhouse Gas Emissions are explained.
Individual data is provided in order to aid in understanding. A detailed overview summarizing the developments over the last five years and the current status can be found in the Appendix.

Photo of permanent chancellor representative Thomas Trännapp and chancellor Manfred Nette-koven in front of a glass wall. Thomas Trännapp with black jacket, white shirt and jeans. Manfred Nettekoven with dark blue jacket, black polo shirt and jeans. Both are smiling at the camera.
from left: Permanent Deputy Chancellor Thomas Trännapp, Chancellor Manfred Nettekoven

The role of sustainability in society and industry has changed significantly over recent years. Environmental disasters and the now undeniable problem of global warming with huge impacts on the Earth’s climate system make it essential to render industrial and societal processes sustainable.

As one of the largest technical universities in Europe, with approximately 47,000 students, 550 professors, 260 institutes, and a campus area of 614.000 m² at present, RWTH is aware of its responsibility. This also applies to the University’ infrastructure and its operations. Here, it is important to use the available resources in the most efficient and sustainable manner. Although research and teaching at RWTH seek to address the major global challenges and thus make a contribution to promoting sustainability, operating a complex and large-scale university infrastructure constitutes a task in its own right when it comes to achieving sustainability.

Making our consumption of resources sustainable on a long-term basis is one of the most important tasks of the Central University Administration. Our goals are necessarily ambitious, and we will be working hard to become even more sustainable in the future. Our declared goal is to further the environmentally sustainable development of all University operations, for example to become a climate-neutral university by 2030, and shape the present in ensure way to ensure a worthwhile future.

That is why we are all working together, not just within RWTH but also with other institutions, including the Building and Real Estate Management Agency of North Rhine-Westphalia, FH Aachen University of Applied Sciences, and the City of Aachen. One aim of our collaboration is to build further climate-friendly public buildings in Aachen. To this end, we are taking the scientific expertise from our faculties and translate it into practical applications in our campus operations. Linking our sustainability-oriented operations with our additional core competencies in teaching, research, knowledge transfer, and student engagement poses an ongoing challenge – but also an opportunity. It allows us to live up to our responsibility as a role model and to use the University campus as a living lab.

Members of the University come from all groups and generations of our society. With open communication and transparent measures, we are attempting to achieve our goal of involving all members of RWTH in this process. We want to make the purpose and value of sustainable solutions comprehensible and apparent for everyone involved.

It is only with the dedication, openness, and willingness of all groups at RWTH that we will be able to make our teaching, learning, and research landscape sustainable in the long term.


Manfred Nettekoven Thomas Trännapp


Permanent Deputy Chancellor


Buildings and Spaces

At RWTH, the construction of new buildings and extensions and the refurbishment, renovation, and operation of buildings are coordinated by Department 10 – Facility Management. The Building and Real Estate Management (BLB) of North Rhine-Westphalia owns almost all of the state’s real estate and rents its properties to state authorities and public institutions such as RWTH. In collaboration with the owner BLB, RWTH has erected a large number of new buildings over recent years and has also renovated existing buildings. Due to today’s high energy standards for new buildings and certain renovations, it was possible to sustainably reduce the University’s resource consumption as captured, in particular, by RWTH’s space-related heating energy consumption characteristic value (see Section Energy Supply).

The BLB is the lessor, but not the operator, of RWTH’s buildings. The University itself is responsible for technical facility management as well as some construction measures that are required for maintenance purposes. In addition to managing new buildings and renovations, RWTH also undertakes a large number of measures in its function as building operator.
RWTH and BLB work together on major projects, renovations, and new buildings. The University actively addresses, requests, and encourages upgrades to existing PV systems, for example, as well as other efficiency measures designed to achieve climate neutrality. These are implemented by the BLB in their maintenance activities.

The primary objective of the Facility Management Department is to ensure that the buildings can be used for teaching and research at all times without disruptions. Any additional demand for large lecture halls is being compensated for, in part by temporary buildings, so that the upcoming maintenance work can be carried out without restrictions. The buildings can also be used efficiently to provide study spaces or examination rooms in the lecture-free period.

Creating a welcoming space, the University campus features design aspects such as greenery and plantings, floor coverings, street lighting, and seating – especially benches – bicycle stands, waste containers, and signs. In many places, we have already succeeded in integrating sustainable alternatives, e.g. by cultivating wildflower meadows to support biodiversity or switching to LED lighting. Other projects, however, can only be realized in the medium or long term, such as establishing consistent waste separation in the buildings, as this poses major logistical challenges.
The walls surrounding the flowerbeds have already been cleaned and then modified to provide seating on the University Library grounds, for example. More seating is also to be created in various other areas on Campus Mitte in order to encourage people to stay and linger there. To prevent littering, new waste bins and ashtray stands were installed in areas with increased waste volumes.
When re-designing the green spaces in the Campus Mitte area, a key concern is the sustainability and upkeep of the green spaces and flowerbeds to promote biodiversity and ensure a long-term enhancement of the campus area. University Management was supported by the Institute for Environmental Research during the design and planning stages.
RWTH buildings extend across the entire urban area of Aachen – Aachen Mitte, Hörn, Melaten, and, in the near future, Aachen West. Due to its development over a long period of time, the University has established complex energy and water supply structures. This poses major challenges but also opportunities when it comes to a sustainable energy and resource supply.

Energy Supply

Flow diagram energy flow of RWTH. Heat shown in red, natural gas in green, electricity in yellow, heating oil in black and cold in light blue. The volume of the energy flows shows the thickness of the lines. From left: Starting points are the purchased energy sources (district heating, heating oil, natural gas, electricity) on the left - blue pictograms with white symbols. District heating flows directly into consumption. The little purchased heating oil flows into the boiler. Natural gas flows into the boiler, little directly into the lab gas consumption and much into the CHP. The large amount of purchased electricity goes directly to consumption. The 2. level is formed by the boiler and the CHP unit. From the boiler, little heat goes to heat consumption and very little natural gas goes to losses. From the CHP, heat goes to consumption, absorber and losses. Electricity goes directly to consumption and small amounts to absorbers and compressors. The 3. level is absorber & compressor.
Energy Flow at RWTH

The University’s energy supply is provided via its own networks for district heating, natural gas, electricity, cooling, compressed air, and water. With the ever-growing number of buildings and the increasing use of building technology, the requirements regarding energy and water supply are also becoming more and more demanding.
For over 15 years now, we have tracked energy consumption and externally sourced energy has been presented in regular Energy Reports. These have been used to account for the consumption and cost data, monitor energy and drinking water use, and record emissions since 2000.

One focus of the work to date was to establish an energy controlling system and, in particular, to upgrade the equipment to measure all energy flows, so that energy use and costs can be determined for each individual building. In addition to setting up a comprehensive meter network, an energy database was developed with the aim of recording essential information via the nearly 800 meters currently in use. Of these meters, approximately 150 are billing-relevant measuring points for energy, approximately 400 are for the RWTH supply networks, and approximately 250 are water meters. Implementing an energy data management system will allow us to record and evaluate the data from all meters regardless of the manufacturer, which will, in turn, permit better forecasting and help optimize energy sourcing and consumption sustainably.

The Energy 2025 master plan seeks to optimize and modernize the energy supply infrastructure on a continual basis. In order to lower the University’s increasing energy costs and address the economic and environmental significance of the topic of energy in general, RWTH has created a dedicated organizational unit (10.36 Division Energy Management and Technical Project Coordination) in order to continually and systematically expand the University’s energy management system.

The developments in energy consumption and floor space from 2016 to 2020 are shown in individual graphs per year. The year is in a medium-sized, dark blue circle. On the right semicircular surroun-ded by four smaller circles as well as data. Inside these are white symbols. A plug for electricity, heating for heating energy (HE), thermometer for cooling energy (KE), for net floor area two hills with a pin in the middle.  2016 and 2017 are shown on the top half of the graph, 2018, 2019 and 2020 on the bottom half. 2016: 106839 MWh electricity, 114878 MWh HE, 31348 MWh KE, 666981 m2 net floor area. 2017: 107712 MWh electricity, 107402 MWh HE, 31775 MWh KE, 706253 m2 net floor area. 2018: 110481 MWh electricity, 103106 MWh HE, 32769 MWh KE, 706062 m2 net floor area 2019: 1114111 MWh electricity, 109131 MWh HE, 33204 MWh KE, 708886 m2 2020: 107074 MWh of electricity, 101313 MWh of HE, 30589 MWh of KE, 725723 m2 of net floor area.
Development of Total Energy Consumption and Net Floor Area

To supply all University-managed buildings with energy, RWTH purchases district heating, natural gas, and electricity from external energy suppliers.
The majority (80%) of the purchased district heating is fed into an internal University network to supply the buildings in Campus Mitte and Campus Hörn, where it covers two thirds of the heating energy requirements. The waste heat from the electricity production at the Wüllnerstraße combined heat and power plant provides the remaining third.
At the Melaten expansion site, a lower proportion (10%) of the heating energy supply is covered by district heating, with the majority (90%) being provided by the natural-gas-powered boiler in the heating and power station. Energy is also distributed via the University's own supply network.
In addition to the University’s central heating supply, there are other localized supply points for district heating and natural gas in various buildings and building complexes at RWTH. These comprise 12% of the overall heating energy requirements.

More research requires more energy. The amount of energy purchased from energy providers in the form of natural gas, district heating, and electricity increased by approx. 33% in absolute terms between 2000 and 2020. In light of the simultaneous increase in surface area (+ 65 %), however, this corresponds to a decrease in the specific energy consumption value (energy consumption per square meter) of approx. 30%.
RWTH’s heating energy consumption per square meter almost halved between 2000 and 2020 (- 43 %). The heating energy requirements of the University buildings in the Melaten area are mainly covered by the natural-gas-based heat generated by the University’ heating and power plant.

While RWTH succeeded in significantly reducing specific heating energy consumption, the area-related specific energy consumption remained almost constant (- 5 %) between 2000 and 2020 despite the use of modern building automation systems and new efficiency technologies. This is mainly due to the constantly increasing use of technology in the research facilities of our institutes as well as the increasing net floor space due to the ever-growing number of students. A building’s energy standards also have an impact on energy consumption. Due to the high heating energy consumption values, there is a greater demand for energy-related modernizations in the Melaten area than in the central campus area.

Until 2003, the energy demand was met exclusively by external electricity companies. In 2004, the University put its first combined heat and power plant into operation, which allowed it to reduce the amount of externally sourced energy at the Melaten supply point by a third by 2011. A second combined heat and power plant was put into operation at Campus Hörn in 2011, and a third on Wüllnerstraße in 2017. The three combined heat and power plants generate around a third (35 %) of RWTH’s entire electricity requirements. The waste heat is partly used to generate absorption cooling (Melaten and Hörn combined heat and power plants) to cover the cooling requirements of the RWTH IT Center at the Hörn site, and is partly fed directly into the RWTH heating network (Wüllnerstraße combined heat and power plant).

RWTH’s water consumption has remained almost constant over recent years. At the RWTH cooling plants, several thousand cubic meters of water evaporate every year. Drinking water is also required for air humidification in the air-conditioning units. Water meters determine the volume of water that evaporates every year and does not generate any wastewater.

 In addition to generating direct energy savings, projects implemented as part of local energy analyses also help RWTH gain knowledge that can be used to provide advice to users within its various institutes. Based on the energy consumption characteristics, the focus is currently on the areas of lighting, localized cooling systems, and measures from the Energy 2025 master plan. The pilot projects for converting to LED lighting will serve as an example and are presented at the end of this section.


Representation of an office. From individual elements, lines go upwards, at the top of which sustainability certificates are noted that are required at RWTH for the respective product category.  From left:  Office chair and desk: Office furniture - FSC PEFC, ISO 14001 Monitor with keyboard and mouse: IT clients - ISO14001, Energy Star, Blue Angel Tea cup: catering - UTZ, Rainforest Alliance, Fair traded (Fairtrade, GEPA) Printers: Multifunction devices - Blue Angel, Energy Star Paper stack: Paper - Blue Angel, 100% recycled
Sustainable Product Requirements

Since the most recent change to § 97 of the German Act Against Restraints of Competition (GWB) dated April 4, 2016, procurement law states that social and environmental aspects must be taken into account alongside the criteria of quality and innovation when awarding contracts to service providers.
In addition to observing these regulations and committing itself to the principle of freedom of research and teaching, RWTH’s Division 7.3 – Central Purchasing always strives to meet sustainability requirements in the many spheres of action of a technical university. Procurement thus seeks to provide the University with products and services that are sustainable with respect to environmental, social, and economic aspects.

In every tendering procedure, bidders are currently requested to fill out a form detailing the sustainability measures they have put in place. (Additional information for employees can be found on the intranet - see Division 7.3)
When procuring scientific equipment, the primary focus is on product features and performance criteria in a narrower sense. In some product categories, sustainability aspects are indicated by seals and certificates. For example, any wooden office furniture RWTH purchases is only sourced from timber from PEFC- or FSC-certified forests. All office and seminar room furniture, including rotating chairs, come from ISO 14001-certified factories. Workshop and laboratory furniture, however, is too diverse for general product requirements to be defined.

Catering contract partners are obligated to offer only brands of coffee, black and green tea, and drinking chocolate certified with the Fairtrade or Rainforest Alliance seal or the UTZ label. The RWTH Purchasing Portal (discussed in the following section), has offered Fairtrade coffee for hospitality purposes in addition to conventional coffee since May 2020.

Since as early as 2012, recycled paper has been procured as the standard paper, and is used by the Central University Administration in particular. Apart from special paper for certificates, printed images, the print shop, and paper for representative purposes, only recycled paper is offered on the RWTH Purchasing Portal. By decision of the Rectorate and the Elders Advisory Council of June 2021, publications of the Rectorate as well as the Central University Administration will be printed exclusively on recycled paper certified according to the Blue Angel, procured by framework contract. Furthermore, the need for print versions of publications is to be considered.

In the area of IT deliveries, resource efficiency and eco-friendly requirements are reliably met thanks to the stipulation that products be ISO 14001, Energy Star, and/or Blue Angel (RAL ZU 171) certified. This applies to IT devices such as desktop computers, micro PCs, workstations, notebooks, tablets, monitors, and multi-function devices. In addition, supplementary regulations may define energy consumption limits for the devices.
Over 11,000 end devices have been purchased in total for the new telephone conferencing system that has been in operation since mid-2019. Bidders to this tender were requested to provide comprehensive documentation to demonstrate the environmental friendliness and energy efficiency of the devices. The University also makes eco-friendly business cellphone options available to staff, such as the fully sustainable Fairphone, however, this is currently only being used by one individual.

Bar chart showing the development of paper demand from 2016 to 2020.  The bars are each shown as stacks of paper. The number of sheets is indicated at the end of the stacks. From top to bottom:  2016 - 32 million  2017 - 30 million  2018 - 24.3 million  2019 - 24.6 mil.  2020 - 10.9 mn.  The 2016 figure was estimated by the 7.3 Central Purchasing Department.
Development of Paper Usage I Note: Figure for 2016 was estimated by Division 7.3 – Central Purchasing

The biggest contribution to saving resources is to avoid consuming them in the first place.
The recent decrease in the procurement of copy paper at RWTH has not only been due to the introduction of work-from-home arrangements during the COVID-19 pandemic, but also due to the surge in digitalization at RWTH.
Launched in May 2020, the RWTH Purchasing Portal is the largest of the University’s many online portals. In 2019, approximately 10,000 online orders were processed via all portals, approximately 5,000 orders by the time the Purchasing Portal was launched. An additional approx. 40,000 paper order forms are issued every year for non-digital procurements. The expansion of the RWTH Purchasing Portal is expected to reduce this number. In addition, a digital version of the order forms is being developed as an alternative to the paper format. This will be modeled on the eBANF process.

In addition to its digital systems for document and contracting management, Division 7.3 Central Purchasing also set up a digital workflow for e-invoices and eBANF (electronic purchase requisition format) in June 2020. The aim is to achieve the highest possible level of digitalization when it comes to transaction and invoice processing, thus creating a paperless process. The eBANF system provides an electronic form with a simple approval workflow within a university institution. Receipts are now simply scanned rather than copied, and forms are no longer printed out since they are forwarded electronically instead. The aim is to have as many suppliers as possible send their invoices to RWTH directly via email.
This will lead to a significant reduction in the amount of paper and toner being used, and will lead to workplace printers being replaced by shared multi-function devices and scanners.
The eBANF system, the digital invoice processing system, and the electronic workflows also contribute to a considerable increase in efficiency for the University’s Finance Department in that mail delivery times do not have to be taken into account anymore

The surge in digitalization is significantly affecting many different areas of the University beyond the processes described above. One example of this is the introduction of the digital signature function. Numerous forms used by the Central University Administration have been upgraded to include this function, meaning they can be filled in digitally. The aim of this is to reduce the number of printed and copied documents, a goal which is also reflected in the steady decrease in the procurement of copy paper (see Figure).
Digitalization processes in this area often have additional sustainability impacts besides the environmental benefit of resource savings. In the University Library, for example, 15 photocopiers for use by students have been replaced with scanners. As well as saving paper, this provides students with an additional benefit: Unlike making photocopies, scanning documents is free.

Waste Balance & Disposal

The Building Logistics and Environment Section of Department 11 – Infrastructure is in charge of waste disposal at RWTH. The Waste Management Service Center (SCA) serves as an intermediate waste storage facility at RWTH and thus as an interface between the institutions as waste generators and the public and commercial disposal companies.
The waste that is generated at the University can be roughly divided into two categories: hazardous and non-hazardous waste. Hazardous waste is primarily generated in the teaching and research institutions. This includes, for example, laboratory chemicals, waste oils, slurry from wastewater treatment plants, as well as dyes and paints or old electrical equipment. Non-hazardous waste includes wood, metals, glass, plastics, paper, and non-recyclable waste.
Measures to protect raw materials and resources include waste prevention, waste reduction, and recycling. In order to prevent waste, the University institutions are required to consider whether planned procurement is really necessary. This is the most important requirement to prevent the waste of resources. However, it is difficult to prevent the generation of hazardous waste that is required for teaching and research purposes, such as laboratory chemicals. Nevertheless, the institutes now have the option of trading any chemicals they no longer need with other institutes. Thanks to the Occupational and Radiation Protection Staff Unit, they have access to the DAMARIS hazardous substance information system that, in addition to creating hazardous materials registers and operating instructions, also features a platform for exchanging chemicals.
Another contribution to resource conservation is the introduction of waste containers based on renewable raw materials. The SCA has replaced some of the conventional plastic containers for the disposal of chemicals with bioplastic containers made from sugar cane.   
To increase the recycling rate, containers can be set up in locations where large amounts of waste is generated, either regularly or temporarily. The SCA provides red recycling containers for mixed recyclable materials such as wood, metals, and plastic transport packaging. All non-hazardous waste can also be delivered to the SCA depot following prior notification. Additional information including a list of all types of waste and detailed information regarding their disposal can be found on the intranet page of the Waste Management section.
There is also potential for expansion and improvement in the area of municipal waste. Up to now, this waste has been separated into only two categories: Mixed paper and cardboard, and non-recyclable waste. The challenges posed by a more differentiated waste separation system include sorting mistakes and a lack of space for additional containers, particularly in the central campus area. The University’s waste concept is currently being improved with respect to resource conservation. Alongside awareness-raising measures, it is now being evaluated in pilot projects, seeking to implement, for example, the separate collection of waste packaging (“yellow bin”). The success of such projects not only depends on appropriate technical framework conditions being in place, but also on the participation of staff and students. These factors are also being evaluated on a site-specific basis in students’ final theses, whose results enjoy a high level of acceptance within the University’s faculties and institutes.
Since the University institutions are spread across the city and vary widely with regard to their spatial conditions and the generated waste, it is not possible to develop a uniform waste concept for the entire University. Instead, the plan is to develop specific waste concepts for the individual sites, taking into account various aspects such as spatial conditions, public accessibility, the types of generated waste, and the proportion of staff and students among the users of the building.
Another focus is to expand waste advising on the opportunities offered by the various disposal channels and their environmentally friendly usage.


Transport mode use of RWTH employees for commuting to work by mode of transport in each case for 2010, 2013, 2016.  The upper and lower halves are each divided into four sections. The symbol for the mode of trans-port is on a line in each case. The percentages and pie charts are shown above this. Above this, the means of transport is named. From top to bottom right: Walking, represented by one person, 2010 12%, 2013 7%, 2016 9%. Bicycle, represented by one bicycle, 2010 11%, 2013 12%, 2016 16%. Car riders*, represented by a car, 2010 53%, 2013 44%, 2020 42%. Passenger car riders*, represented by one passenger car and three people, 2010 5%, 2013 2%, 2016 3%.  Motorized two-wheeler, represented by a motorcycle, 2010, 2013 and 2016 less than 1%. Bus/train, represented by a bus, 2010 19%, 2013 33%, 2016 30%. Other transportation, represented by a pe-dal scooter and a skateboard, less than 1% in 2010, 2013, and 2016.  Development 2010-2016: bicycle + 11%, bus/train + 11%, car drivers* -14%.
Means of Transport Used by RWTH Employees for Their Commute I Source: Survey of the Chair and Institute of Urban and Transport Planning

RWTH recognizes mobility in two distinct forms – mobility at and to RWTH for work, and teaching and learning purposes and mobility in terms of business travel.

RWTH’s vehicle fleet currently features over 30 vehicles with combustion engines. These include buses (used for excursions, for example), vans (for transporting loads between sites), and passenger cars. Two electric vehicles have been purchased for internal mailroom services as well as grounds maintenance and waste disposal services. In addition, the Rectorate’s vehicle of choice since 2020 has been a more environmentally friendly hybrid car. An electric delivery bicycle is also being used for mailroom services, delivering mail, and carrying out errands on university grounds.

The City of Aachen encourages bicycle use with the Velocity system by funding multiple rental stations for electric bicycles across RWTH’s campuses. For other means of transportation, students pay a semester fee, financing a Semester Ticket that entitles them to use regional buses and trains in North Rhine-Westphalia as often as they like, enabling them to benefit from cost-effective public transport. Employees also benefit from special transport incentives – on average, almost a third of employees who are entitled to a Job Ticket end up purchasing this subsidized ticket, allowing them to use public transport in the local area and neighboring municipalities -> Job ticket validity (PDF).

 Focusing on medium-term goals and participatory design, the working group for Student and Staff Mobility Development by 2025 was set up in 2019. It consists of representatives from all University groups, the staff councils, the Representative Council for Staff with Disabilities, Central University Administration divisions 5, 9, and 10 as well as the Chair and Institute of Urban and Transport Planning (ISB). The Rectorate assigned this group the task of developing a long-term and sustainable mobility concept and encouraging students and staff to switch to more sustainable means of transport, such as by expanding the network of charging stations for electric cars and increasing the number of secure bicycle spaces.
This strategy also includes plans to carry out a mobility survey among staff and students in order to establish average commuting distances. This survey will be performed by the Chair and Institute of Urban and Transport Planning once commuting patterns return to normal following the pandemic.

Part 1 of 5 decision tree for air travel Parent: Do I have time to attend the event?  How far is the journey and what will I miss if I don't at-tend? How important is the date - is my presence necessary? Connected to this is a dark blue text field: Do I want/need to attend the event? From this a line with two branches: above - yes, another connecting line continues to the right. Below it no: a connecting line to the text "no participation".
Part 2 of 5 decision tree for air travel Parent: Is virtual participation possible?  Does physical attendance have significant advantages over virtual attendance?  Does the occasion require my physical presence? Can I combine my travel with other appointments?  Connected to this is a dark blue text field. A connecting line leads from the left edge of the image to the field. In it the text: Do I want/need to attend the event? From it a line with two branches: above - yes, another connecting line continues to the right. Down - no: a connecting line leads to the text "By your virtual participation you reduce your carbon footprint for this event, thank you!".
Part 3 of 5 decision tree for air travel Superordinate: How long does the train or bus trip take compared to the flight (including travel to the airport, check-in, etc.)? Is there a continuous connection? Will there be colleagues or other partici-pants from my area with whom I can travel together? Connected to this is a dark blue text field. A connecting line leads from the left edge of the image to the field. In it the text: Do I have to fly? Are there alternatives to flying (train, bus, car, carpool)? From this, a line with two branches: above - yes, another connecting line continues to the right. Below that, no: a connecting line leads to the text "Thank you for your commitment to sustainable RWTH!".
Part 4 of 5 decision tree for air travel Superior: Is there a direct flight? Is the flight offered by CO2 efficient airlines?  Connected to this is a dark blue text field. A connecting line leads from the left edge of the image to the field. In it the text: Do I want to compensate?  From this a line with two branches: above - yes, a connecting line leads upwards to the text "Inform yourself here about possibilities to compensate your flight: www.umweltbundesamt.de/themen/freiwillige-co2-kompensation". Another connecting line continues to the right.  Below no: a connecting line leads to the text "Have a good trip!".
Part 5 of 5 Decision tree for air travel A connecting line from the outer left edge of the image to a dark blue text box: "Offsetting your CO2 emissions can support projects for a better climate footprint. Thank you and have a good trip!"   Below a note: For more information on sustainability at RWTH, click here: www.rwth-aachen.de/nachhaltigkeit

Business travel is one of the greatest causes of emissions at universities – whether it involves flights, journeys in private cars, a rental/leased vehicle, or train journeys. Business trips essentially reflect a structural sustainability dilemma between the University’s climate-protection obligations and its pursuit for research internationalization. The question of which objective should be given higher priority cannot be answered in general terms; instead, each individual should evaluate their individual case, taking into account aspects relating to climate policy. The State Travel Cost Law attempts to take this into consideration, promoting an environmentally friendly mode of travel by stating that business trips should usually be taken using public transport. Therefore, a large number of business trips by members of RWTH are taken by train (Deutsche Bahn), as can be seen in the business trip data in the Appendix.

When it comes to promoting sustainability and climate protection, we naturally focus on air travel, in particular. Over recent years, the number of business trips by members of RWTH has continued to grow and has now settled at a high level.
Since global exchange is essential for a university, particularly its researchers, the use of video conferencing systems is being expanded and promoted as part of digitalization initiatives. The virtual semesters that have been a feature since the start of the Covid pandemic also show the strengths of these systems as well as the continued success of international collaborations. These factors need to be integrated into everyday university life in the future in order to improve virtual communication and, in turn, reduce the increasing number of environmentally harmful business flights.

In the future, aspects relating to environmental compatibility and sustainability will also be directly taken into account in the State Travel Cost Law in order to meet climate protection requirements to a greater extent with regard to reducing CO2 emissions for business trips.
Aspects include the consideration of environmental factors (low CO2 emissions) in addition to a purely economic assessment, but also the increased use of virtual communication options as well as incentives for the use of public transport and, in particular, trains.

In order to raise awareness of the environmental impacts of personal mobility at RWTH, the University is planning to promote internal projects, such as a climate fund, as possible carbon offset options, in addition to active communication such as via the decision tree for air travel (see Figure).

Greenhouse Gas Emissions

Representation of the CO2 emissions of the RWTH as a bar chart.  The columns are represented by dark blue clouds coming out of a smokestack. On this is a small dark blue circle with symbol for the emitter.  From right:  Electricity purchase, symbol electricity plug, 28,668 t. CHP, symbol chimney, 18,484 t. Heat, sym-bol three vertical waves, 14,962 t. Business travel, symbol airplane, 6,429 t. Fleet, symbol car, 183 t.  Above the graphic, a medium blue box reads: Total emissions 68,920 t.
CO2 Emissions (Excerpt) I Source: Own representation based on calculations with the greenhouse gas calculation tool of the startup CO2OP.

In total, the annual greenhouse gas emissions resulting from the operations of RWTH currently amount to an annual CO2 equivalent of over 68.000 metric tons, which corresponds to 110 kilos per square meter of effective area or 1.2 metric tons per university member.

The consumption data from 2020 provide the data basis for this figure. In the areas of business travel and vehicle fleet, we have used data from 2019 in order to reduce distortions resulting from the coronavirus pandemic. Comprehensive data is available in the appendix.

The emissions data for energy purchases were previously provided by energy suppliers. For 2020, data was collected more comprehensively for the first time and was based on other data available at the University. The data was collected using a greenhouse gas calculation tool developed by startup CO2OP. The startup emerged from the Hochschule für Technik Stuttgart as part of a startup grant program.
The tool follows the specifications of the internationally recognized Greenhouse Gas Protocol standard.

The energy emissions figure for 2020 calculated in the more comprehensive data collection is higher (7%) than the figure submitted by energy suppliers.

The amount of greenhouse gas emissions generated from energy consumption largely depends on the specific emissions (tCO2/MWh) of the respective energy sources purchased by RWTH. Although the amount of purchased electricity has continued to rise over the past 15 years or so, we have seen huge fluctuations in the associated CO2 emissions per kWh of purchased electricity. The demand for natural gas is permanently rising due to the combined heat and power plants, of which there are now three. At the same time, however, the total amount of purchased electricity and heating is declining, which evens out in the emissions balance.

The University’s Melaten heating and power plant is required to participate in the emissions trading scheme. This means that RWTH has a duty to hand over certificates to the German Emissions Trading Authority (DEHSt) for the CO2 emissions generated on site. RWTH purchased certificates costing almost 700,000 euros for 2020 alone. Due to the generally increasing demand for certificates, the prices in 2021 will probably rise even further.

In order to make RWTH more sustainable in this area, more comprehensive data collection regarding greenhouse gas emissions is planned for the future in accordance with the Greenhouse Gas Protocol. At the same time, the University is actively working on reducing its greenhouse gas emissions in line with its goal to become a carbon-neutral university by 2030.

In the pursuit of this goal, individual measures are being critically reviewed and scrutinized during discussions at the University. One such example is the suggestion to use green electricity as a way of reducing CO2. A global effect will only be achieved if conventionally generated electricity is replaced by electricity that is generated in a way that is actually renewable and not – as is sometimes the case – merely leads to trade-offs between countries with a high proportion of electricity from hydropower (e.g. Norway) and those with a high proportion of conventional electricity (e.g. Germany).

The basis for calculating the emissions data for business air travel is information provided by the University's contracted travel agencies. Two of the three contracted travel agencies were able to provide data on the passenger air kilometers traveled as well as the resulting emissions. The total figure calculated was based on the proportion of revenue generated by  the three travel agencies.
For 2020, emissions from air travel were also calculated using the greenhouse gas calculation tool previously mentioned. The calculated figure is higher (4%) than the data submitted by the travel agencies.

The emissions data currently available are in the appendix of this report.

Example projects