Saving energy together: Information from the University of Stuttgart

By closing university buildings for two weeks at the turn of the year 2022/23, we were able to save 17.5 percent of heat consumption compared to the same period in the previous year. In the period from December 2022 to January 2023, this corresponded to a saving of 4300 MWh compared to the previous year (absolute value, not adjusted for degree days). The weather was significantly warmer than "normal" during lockdown in December 2022, the savings potential could be higher this winter, depending on the weather.

In comparison to New Year 2021/22, electricity consumption was reduced by around 5 percent due to the building closure in 2022/23. The savings in the months of December 2022 and January 2023 amounted to 850 MWh. The HLRS, which has a very high energy consumption, was fully operational during this time, which was also reflected by the low percentage figure.

Based on our experience of saving energy over the new year period 2022/23, the university currently assumes that, if weather conditions are comparable and if the plans are largely implemented, savings of 6 to 8 percent in electricity consumption and around 25 percent in heat consumption can be achieved during the four energy-saving weeks.

Ultimately, each and every one of us is responsible for the success of the energy saving weeks. We can only achieve meaningful savings overall if everyone makes a contribution. The university therefore asks for your help, creativity and support in implementing energy-saving measures and the development of energy-saving opportunities - even beyond the Energy Saving Weeks.

It is important to differentiate here. Many obvious deficits result from the backlog of renovations required on the university's buildings The university's influence in this regard is limited. Measures are required that take a long time to prepare and depend on state funding. Renovations are planned (for example, the redevelopment of the two NWZ high-rises), but the timeframes for implementation range from many years to a decade. Many medium-sized measures (minor renovations, conversions, ...) can be carried out by the university itself. However, the time required for planning, tendering and commissioning external companies, and for the implementation must be taken into account. Such measures are being carried out continuously.

Then there are a large number of small measures that we can implement ourselves - we need to get better at this! The problem here is the very limited human resources available in the relevant areas. Employees in these areas are already working at full capacity and unfortunately cannot invest as much time as they want in additional tasks (as energy saving has become).

In the end, what remains is the simple tasks that each and every individual in the university can carry out themselves (switching off lights, shutting down computers, turning down radiators in empty rooms, ...). 

Essentially, university buildings are not owned by the University of Stuttgart, but by the state of Baden-Württemberg. The state has assigned the task of building renovations to the University Building Authority. The state allocates funds from its budget for this purpose to the University Building Authority. The financial resources allocated each year are limited and are only sufficient for a small part of the necessary renovations. Furthermore, these refurbishments must be registered in the state budget in advance, and they also have to be approved by the state. 

The University of Stuttgart may commission repairs up to € 10,000 (net) directly on behalf of the University Building Authority. But any repairs that cost more than this are the responsibility of the University Building Authority.

Firstly, the payback period for PV systems is around 20 years, and secondly, structural constraints - statics, roof superstructures, fire protection (penetration of several floors with new power lines to the building's main distribution) - must also be considered. Even if we equipped all roofs and major facades with photovoltaic panels, the self-generated share would only be a very small percentage of the total energy required.

The ultimate goal is to ensure that employees, students and visitors can move (and work) safely in the buildings. Lighting is also subject to requirements specified in the workplace ordinance (ASR). This means that, in order to meet these requirements, appropriate lighting must be in operation as soon as a person moves in a corridor.

One solution to this problem is to equip the lights with motion detectors and/or brightness sensors in hallways. However, since this entails certain technical requirements, implementation is not possible everywhere at present due to our building fabric, some of which is very old, and the technology installed in it. 

Work has already begun on equipping buildings with sensors. However, since the University of Stuttgart uses a large number of buildings and very many measures are running simultaneously, this project will be implemented gradually. Some retrofits are only possible during extensive building renovations.

For example: Why should I turn off my monitor or lights after work and turn down the heating when the data center consumes much more electricity and thermal insulation would save much more energy?

Why not do one thing, when something else would be much better? The goal is to address both options and to implement what is possible. We are all responsible for ensuring that resources are used carefully and wisely. If we are to be successful, then each and every one of us must do what is possible for them.

Not all measures that would reduce energy consumption are the direct responsibility of the university. Our room for maneuver is often limited and implementation can take much longer than we would wish.

No, but most of the energy meters (electricity, heat, cooling, gas, and water) can be read remotely, and are recorded every 15 minutes.

In rented properties that are not on the university campuses, (Vaihingen and Stadtmitte), direct access to the main meters of the energy suppliers is unfortunately not possible. In these properties, we have installed submeters that can mostly be read remotely, via which the total consumption of the building can also be recorded on a 15-minute basis.

In addition, the meter infrastructure of the university does not allow a very high "selectivity": Many readings can only be recorded for an entire building. It is not possible to separate institutes or facilities within a building. 

If you notice that energy is being wasted, contact your energy officer if possible. If you do not know which energy office is responsible in your case, you can send an email to the energy manager.

Campus Vaihingen has a high energy demand due to its size and some very energy-intensive equipment and installations. To ensure supply security and save costs through load management, a combined heat and power plant was built in the 1960s to supply Campus Vaihingen and external institutes and facilities with district heating as well as electricity via its own independent supply network.

As the name suggests, the combined heat and power plant (CHP) is heat-led and covers the heat requirements on Campus Vaihingen. The CHP plant also produces electricity as a kind of "by-product" using efficiency-optimized combined heat and power generation and thus covers a good half of the university's annual electricity requirements on Campus Vaihingen.

The university covers its additional electricity requirements by purchasing electricity from 100 percent renewable energy sources. The power plant can be operated flexibly, which also serves to avoid purchasing electricity during expensive electricity peaks - caused by numerous large-scale test facilities. This actively helps reduce costs.

The Pfaffenwald combined heat and power plant supplies Campus Vaihingen with district heating by means of cogeneration, covering a good half of the electricity demand at the Vaihingen campus. Another nearly one percent of the electricity is supplied by the PV systems on campus, the remaining electricity is purchased and comes from 100% renewable energy sources.

District cooling is generated in two cooling centers (at the HKW to the north and at the Computing Center to the south) with electrically operated compression chillers.

The buildings in the city center (including around the Stadtgarten, Böblingerstraße and in Azenberg) are connected to the district heating network of the energy supplier EnBW. More remote properties usually have gas heating systems. Outside Campus Vaihingen, electricity is supplied via the state's annual tenders (100% renewable green electricity since 2015).

The combined heat and power plant at the Vaihingen campus provides heating for the entire campus and generates a good half of the university's electricity requirements through cogeneration. In addition, the power plant supplies the high-pressure steam needed for some large-scale test facilities in the north of the campus.

The power plant itself runs on natural gas, but can switch to fuel oil, which helped us influence costs this year when gas prices were high.

In the cooling centers, district cooling for air conditioning is provided via compression chiller systems.

Slightly over half of the electricity consumed by the university facilities on the Vaihingen campus is generated via cogeneration in the Pfaffenwald combined heat and power plant (CHP), while the latter supplies the entire campus with district heating. The university's own PV systems contribute just under one percent of the electricity supply.

Electricity demand beyond that generated on campus has long been purchased as green, CO2-emission-free power. This reduced the CO2 footprint resulting from electricity supply by more than a third.

Due to the size of the supply area and the amounts of energy required on campus, transitioning the energy supply toward carbon neutrality, while maintaining supply security is a very challenging task. This can only happen in cooperation with various players: the city of Stuttgart with its municipal heating planning, the state as owner, and the network operators as energy suppliers.

Replacing these depends on a few technical specifications. Very old bulb fittings (mostly from the 60s and 70s) cannot reliably support the somewhat heavier weight of LED tubes. Newer fixtures with electronic ballasts ECGs (circa 90s) require special LED tubes that can "trick" the ECGs into not generating a start pulse when switched on. Not every ECG allows this, so each lighting fixture must be investigated individually. The current T5 tubes all have an ECG and are 50mm shorter than the corresponding T8 tubes. LEDs with T5 tubes are specialist products and accordingly very expensive.

Together with the University Building Authority, it was decided not to use LED illuminants in places where very old lights are installed, but to gradually replace these with new LED lights.

The simple thermostatic valves and heads - still often found in older buildings (NWZ, ETI, IW) - allow only general control (either a lot of heat, or very little). Here, the average room temperature - measured by means of reference sensors - is controlled centrally via the flow temperatures of the heating sections. Simply not fully opening the valve saves energy.

With newer thermostatic valves, which are being fitted by the University Building Authority, the temperature can be controlled much more easily and individually in each room. The setting 2 on the thermostatic valve corresponds to a room temperature of approx. 16°C, 3 corresponds to 20°C and 4 corresponds to 24°C.

Yes, every room that is not being fully heated saves energy. However, since the buildings are divided into heating circuits, the entire corresponding heating circuit must also be heated in order to heat a single room, which considerably reduces the savings effect in relation to the building. 

The University Building Authority is the office of "Vermögen und Bau Baden-Württemberg" responsible for construction matters at state properties for the University of Stuttgart. As soon as an energy-saving measure involves structural measures on buildings and associated installations/technical systems, such as facade insulation, replacement of heating systems or parts, this is handled by the University Building Authority.

In turn, the University Building Authority is dependent on state funds, as well as the available personnel to implement the measures. 

No, most of the buildings do not belong to the University of Stuttgart, but to the state of Baden-Württemberg, owned by the Ministry of Finance. "Vermögen und Bau Baden-Württemberg" (VUB) is the administrator responsible for all state properties. The University Building Authority is the responsible body of the VUB and thus responsible for structural measures.

The Energy Officers support their colleagues, Division 6 and its Energy Manager, the Green Office and thus the entire university in saving energy. They raise awareness of the need to save energy, inform and motivate colleagues in their facility or institute, implement measures in planned university-wide campaigns, find ways to save energy at their facility and report malfunctions and the need for technical measures to the responsible departments. 

The energy officers perform this task voluntarily; they are put forward by their superiors and supported by them. The energy officers are trained by Division 6 and the Green Office and are in regular contact with each other.

Become an Energy Officer [de]

Prices for gas and electricity are currently falling again after reaching their peak. As the university has concluded multi-year contracts to ensure a predictable and stable supply, short-term fluctuations in energy prices do not affect the university. However, this also means significantly higher energy prices for the university compared to before 2021. 

Reducing energy consumption allows the University of Stuttgart to use the money thus saved for investments, equipment, to fill vacant positions, and, more generally, for its services to all of us.

The University of Stuttgart and its members function as role models in the responsible use of resources in view of the global climate crisis and a strained energy supply situation. Last but not least, the University of Stuttgart - like all state institutions - aims to become net greenhouse gas neutral by 2030. This can only be achieved through a variety of measures that reduce energy consumption, increase energy efficiency, and promote the transition to CO₂-neutral energy sources. Saving energy will therefore remain a necessity in the long term, and this must primarily be implemented through medium- and long-term technical and organizational measures.

Yes! The state government supports state universities to help them meet the additional energy costs. 80 percent of the additional costs for 2023 compared to 2021 will be covered by the state and reimbursed in 2024 [de]. Irrespective of this, the energy savings of 20 percent demanded by the state as a contribution to supporting climate-neutral regional government administration remain in place. This is a joint effort in which the University of Stuttgart must also do whatever is possible to reduce the additional costs by using all reasonable energy-saving means available. 

Reducing energy consumption by 20% compared to 2021 is a step towards keeping the increased energy costs under control and achieving the goal of climate neutrality in the medium term. Everyone is aware that measures with high savings potential require investment and must be prepared before they take effect. 

Like all other universities and colleges, the University of Stuttgart has an obligation to demonstrate that it is using all reasonable and appropriate means to reduce energy consumption and thus costs. Savings of 20% are a guideline that can be achieved on average by large institutions, depending on the framework conditions, investments, and lead times - nevertheless, conditions are not the same for all organizations and their departments. The important thing is that we work together to reduce energy consumption as much as possible.

For the University of Stuttgart, this means that energy consumption will be reduced in all possible areas. This applies to organizational measures as well as technical improvements and behavioral changes. It is not a matter of prioritizing one measure over another, but rather that we as a university implement as many measures as possible. Small individual measures implemented by an employee may not in themselves represent a major reduction in energy consumption. However, if all our employees participate make these small individual measures, we are working together to ensure greater overall reductions in energy consumption. 

Saving heat by reducing opening hours, optimizing occupancy, renewing technical equipment such as heat transfer stations, or renovating buildings are areas that have great potential for savings for the University of Stuttgart.

An overview of measures that have already begun, are being planned, or have already been successfully implemented.

If the University of Stuttgart does not save energy, it will not be able to afford an increase in energy costs running into millions of euros. This is despite the state's promise to cover 80 percent of the additional energy costs. The University of Stuttgart would then have to make savings elsewhere, e.g. by investing less in equipment, in the libraries, in new employees, in teaching and wherever else possible.

This might affect you specifically in your institute or your lectures or internship, but it would certainly have an impact on the equipment and quality of work of employees and students and on the attractiveness of teaching and research and thus on the attractiveness of the University of Stuttgart as a whole.

Conversely, if we successfully reduce energy consumption, this is not only a success for the university as a whole, but also for each and every individual. Saving energy is successful when everyone works together to do whatever is possible.

Slightly over half of the electricity consumed by the university facilities on Campus Vaihingen is generated via cogeneration in the Pfaffenwald combined heat and power plant (CHP), while the latter supplies the entire campus with district heating. The university's own PV systems still contribute very little to the electricity supply (< 1 %). The amount of electricity generated in the combined heat and power plant depends on the amount of heating required over the year.

Electricity demand beyond that generated on campus has long been purchased as green, CO₂-emission-free power. This reduced the CO₂ footprint resulting from electricity supply by more than a third.

Since electricity savings primarily reduce the amount of purchased electricity, we can reduce energy costs and the burden on the environment, but this is not reflected in the university's CO₂ emissions. However, savings in the amount of heating lead directly to a reduction in the amount of CO₂ emitted.

At the University of Stuttgart, as everywhere else in the world, new consumers are constantly being added as a result of growth. In IT, the computing and energy storage power required is also increasing. Despite this trend, we have managed to save electricity and heat in university buildings and infrastructure. However, some of these savings will be eroded by growth.

It is also important to admit that we have certainly not done everything possible to reduce energy consumption. Even simple measures that might not be critical in terms of their impact on our everyday lives, such as switching off lights and computers or turning down radiators in empty offices, are anything but a matter of course. We must work together to improve this!