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Dealing with Data and Water

Sustainability has many aspects to it. Working at UZH also has an impact on the environment. We have compiled a few tips on how you can go about saving your data and using drinking water in a more sustainable way.


Drinking tap water instead of bottled water protects the environment.

When it comes to sustainability, the University of Zurich has committed to ambitious goals. To make sure these goals are achieved, UZH is taking various measures, including in its real estate planning and building maintenance, air travel, materials sourcing and food services – but also in the area of teaching and research. (Link).

But UZH members also play a crucial role. The UZH sustainability team has therefore put together a comprehensive list of useful tips for everyday life at the university, including advice about commuting, food, IT equipment and organizing events. (Link)

This article contains tips on two additional areas. In his Master’s thesis, informatics student Jeremy Kubrak recently calculated the energy demand of storing electronic data at UZH. By following the tips in this article, you can reduce your energy consumption.

Another reason for this article is UZH’s recent membership of the Blue Community network, which promotes sustainable use of drinking water.


View into the area of a UZH data center with servers, which store the data for the institutes.

Sustainable data storage

As an institution of learning and research, UZH generates new data on an ongoing basis – and this of course requires energy. Electricity consumption for UZH’s storage systems amounts to 560 megawatt-hours. This results in 12.5 tons of CO2 per year, Jeremy Kubrak has now shown in his Master’s thesis (see box).

The amount of data UZH stores has increased steadily over the past few years. At present, UZH’s data processing centers provide storage of 20 petabytes, or 20,000 terabytes – double the amount stored in 2019.

We can help counter this development by storing our work-related data in an energy-efficient and environmentally friendly way.

Here’s how:

  1. Avoid redundancies: Don’t save your data in the cloud as well as on your organizational unit’s shared drive.
  2. Clean up your personal files once a year and delete any data you no longer need. It’s easier to start with the largest files. A one-hour video file can take up as much space as 10,000 e-mails.
  3. For teams and departments/offices: Clean up the files on your shared drive – after consulting with your IT coordinator. Check whether you’re using the most suitable medium for storing your data. It can help if you categorize your data into “hot”, “warm” and “cold” files.

Hot data are those that you use every day and need to be immediately available. They should be stored on a fast storage device, such as the shared drive. Data on shared group drives, in turn, are stored on the file servers at UZH’s Central IT. Compared to other storage media, file servers eat up the most electricity. 

Warm data are data that you only need to access occasionally. You can save these using block storage with the help of your IT coordinator. This is more energy-efficient, since data are grouped and stored in blocks, either on a single or on multiple Central IT servers. 

Finally, cold data are files that you no longer need but still have to be stored, for example for legal reasons. These data can be moved to a tape library of Central IT. Made up slots for tape cartridges and tape drives, tape libraries have the best ratio of energy per terabyte. Your IT coordinator can order a virtual drive from Central IT to transfer the data.

The amount of volume doesn’t matter when it comes to storing cold and warm data, but it’s important to regularly classify the data. 

  1. For researchers and research groups: Delete any data from previous experiments or trials on an ongoing basis. Once you complete a research project, take some time to tidy up your data storage – and make sure to use the categories (hot, warm, cold) mentioned above.
  2. For teaching staff: Move old recordings of online lectures to a tape drive. 


Eine ideale Trinkwasserquelle: Der Wandbrunnen mit dem Mosaik von Augusto Giacometti im UZH-Hauptgebäude.

Drink tap water instead of bottled water

UZH recently joined the international Blue Community network, whose members recognize water and sanitation as a human right and promote publicly owned and operated water and wastewater services. To achieve these goals, Blue Communities maintain international partnerships and commit to the responsible use of drinking water.

Here’s what you can do to support the cause:

  1. Drink tap water instead of bottled water. The environmental impact of tap water is about a thousand times lower than the impact of mineral water. You can fill up your bottle at one of UZH’s many water fountains.
  2. Offer tap water at receptions, conferences and meetings. You can raise awareness of the issue by setting up a small sign. Put this informal policy into writing in your organizational unit.
  3. For researchers: Consider exploring the topic from a variety of disciplines, including geography, law or economics. If you are already doing research on a water-related topic, please contact the sustainability team:
  4. For teaching staff: You can discuss the Blue Community principles, their implications and challenges with students. Are you already teaching about Blue Communities? Please get in touch with the sustainability team: info@sustainability.
  5. You can promote public discourse about the sustainable use of water resources – for example, by organizing a water-themed event.