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Sustainability

Energy & Water

The space used by UZH must be continuously heated, cooled, lit, maintained and supplied with fresh water to ensure UZH's operation. This consumes energy and water and generates emissions in addition to the emissions caused by the construction and maintenance of buildings (see more on the linked page).
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Table of contents

Developments in UZH's energy requirements

UZH and the Amt für Abfall, Wasser, Energie und Luft (AWEL) of the Canton of Zurich have a measure-based target agreement to reduce energy consumption in the period 2018-2027. UZH has been fulfilling this target agreement since 2018, including in 2023.

The infographic shows the energy demand of UZH's infrastructure by energy source for 2024. In the center are gray icons representing UZH's electricity and heat consumption sources, e.g., lighting, technical equipment such as printers, IT infrastructure, kitchen appliances such as coffee machines, technical laboratory equipment, and heaters. The electricity sources consumed are shown in blue on the left and are partly purchased and partly self-produced. 100% of the purchased electricity comes from renewable energies. In 2024, this was 63 gigawatt hours (GWh) from hydropower. 0.29 GWh in 2024 came from self-production through photovoltaics. The heat sources are shown in orange on the right. In 2024, 34 GWh came from district heating, 9 GWh from gas, 1 GWh from heating oil, and 0.08 GWh from wood. In total, UZH consumed 63 GWh of electricity and 44 GWh of heat in 2024, corresponding to a total energy consumption of 107 GWh.
Graphic: Melanie Lindner

The energy requirement in 2024 has increased in a long-term comparison with 2014, but has fallen compared to the previous year. The comparison with 2022 is more meaningful due to the increase in student numbers and the reduction in energy demand that was nevertheless achieved. The share of renewable energy has remained relatively constant since 2014 and increased again in 2023 for the first time since 2016.
The specific electricity demand per employee and per student has been reduced since 2014. The specific heat demand per employee has also been reduced compared to 2014, while the demand per student has remained the same.

for detailed energy data please see tables

Combination of bar and line chart. It shows the development of UZH's energy demand by energy source in relation to the number of students from 1978 to 2024. On the left y-axis, the energy demand for electricity, district heating, heating oil, wood and gas is plotted as stacked bars, while on the right y-axis the number of people is plotted as a line. The number of students rose steadily from 1978 to 2024, with the exception of a dip in the 1990s, to almost 30,000. Energy demand and energy source quantities fluctuate. In comparison to the rising number of students, however, a decoupling of the number of people and energy demand can be seen in recent years, i.e. savings have been achieved despite the rising number of students. The gigawatt hours of electricity and district heating have had the greatest influence over all years.
Graphic: Melanie Lindner

Electricity

Since 2019, the electricity mix purchased has been generated by European hydropower plants through the purchase of certificates. Every new UZH building is equipped with a photovoltaic (PV) system if the location is suitable. In 2023, UZH produced 0.3 GWh of solar power.
UZH is continuously implementing measures to reduce its electricity requirements. Examples include converting lighting systems to LED and adjusting the temperature of ultra-low temperature freezers in UZH laboratories. Measurements have shown that raising the temperature from –80 degrees Celsius to –70 degrees Celsius per appliance can lead to energy savings of 28 percent.

Heat supply and cooling

UZH mainly covers its heating requirements from district heating and waste heat recovery (from cooling). In 2023, district heating came primarily from the City of Zurich's Hagenholz waste-to-energy plant (51 percent). The rest of the district heating comes from the CO2-intensive combustion of natural gas (32 percent), followed by wood (17 percent) and oil (0.3 percent). At locations without a district heating connection, heating requirements are covered by fossil fuels (oil, gas).
Cooling requirements are largely covered by in-house chillers. Their consumption is included in the electricity requirement. Only a small proportion has to be purchased additionally. 
Heating systems are optimized where possible. Some windows have been covered with a special insulating film on a trial basis to reduce heat loss in summer.

With the construction of the anergy network planned for the Irchel campus, the waste heat from cooling will in future be stored in geothermal probes and used for heating in winter. This will enable UZH to cover almost all of its heating and cooling requirements itself in future, thus reducing the need for purchased district heating.
More about the anergy network (German)

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Development of greenhouse gas emissions from energy demand

Greenhouse gas emissions from energy demand in 2023 have risen slightly compared to 2018. This is due in particular to emissions from district heating, as the district heating mix has deteriorated in 2023 compared to 2018: The proportion of sweepings has fallen, while the proportion of gas has risen.

for detailed energy data please see tables

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Detailed energy data tables

These tables are optimized for screen readers. The superscript numbers are displayed below the «Footnotes» heading.

Sources

The following sources were used to calculate emissions:

  • Electricity: Krebs, L., Frischknecht, R. 2021: Umweltbilanz Strommixe Schweiz 2018, treeze, im Auftrag des BAFU; Verteilung nach Scope 1-3 gemäss Alig, M., Tschümperlin, L., Frischknecht, R., 2017: Treibhausgasemissionen der Strom- und Fernwärmemixe Schweiz gemäss GHG Protocol, Treeze, im Auftrag von Sustainserv GmbH, UBS Fund Management, Die Schweizerische Post, pom+Consulting.
  • District heating: according to KBOB, district heating mix according to ERZ data
  • Natural gas, biogas, heating oil, wood: KBOB, Ökobilanzdaten im Baubereich, 2009/1:2022, https://www.kbob.admin.ch/kbob/de/home/themen-leistungen/nachhaltiges-bauen/oekobilanzdaten_baubereich.html.

Energy demand 2014–2024 (in GWh, unless stated as a percentage)1

Energy 2014 2016 2018 20202 20222 2024

Change since 2014 in %
Energy demand total 98.9 109.3 113.5 108.9 112.3 106.9 8
Power consumption total 61.8 63.7 64.5 62.4 65.4 63.2 2
Heat demand total 37.13 45.6 49.0 46.5 46.8 43.7 18

Energy demand by energy source 2014–2024 (in GWh, unless stated as a percentage)

Energy source 2014 2016 2018 20202 20222 2024

Change since 2024 in %
Electricity purchased 61.8 63.6 64.4 62.3 65.1 62.9 2
Electricity self-produced 
from photovoltaic		 0.002 0.067 0.073 0.152 0.330 0.289 16'610
District heating 29.8 37.0 37.6 35.6 34.7 33.9 14
Heat from gas 5.8 7.2 9.9 9.8 10.14 9.1 56
Heat from oil 1.3 1.3 1.4 1.0 2.05 0.7 –51
Heat from wood 0.2 0.2 0.2 0.1 0.1 0.1 –56

Share of energy from renewable energy sources 2014–2024 in percent6

  2014 2016 2018 20202 20222 2024 Δ 2024/2014 Percentage points 2024/2014
Energy demand covered by renewable sources total 78.3 75.4 73.0 74.1 73.5 7.5 –4 –2.8
Share electricity 100.0 100.0 100.0 100.07 100.0 100.0 0 0.0
Share heat8 42.2 41.1 37.5 39.3 36.4 40.1 –5 –2.1

Specific energy demand 2014–2024 (in MWh/person)9

  2014 2016 2018 20202 20222 2024 Change since 2014 in %
Electricity consumption per employee (FTE) 9.9 9.8 9.5 8.6 8.9 7.9 –20
Electricity consumption per student 2.4 2.5 2.5 2.3 2.3 2.2 –8
Heat consumption per employee (FTE) 6.0 7.0 7.2 6.4 6.3 5.5 –8
Heat consumption per student 1.4 1.8 1.9 1.7 1.7 1.5 6

Absolute GHG emissions from energy demand in Scope 1 according to the Greenhouse Gas Protocol10  2014–2024 in t CO2e

  2014 2016 2018 20202 20222 2024 Change since 2014 in %
Scope 1 GHG emissions total 1'389 1'608 2'018 1'710 1'952 1'267 –9
Heating oil 374 355 390 274 570 185 –51
Gas 1'014 1'252 1'628 1'436 1'382 1'082 7
Wood 0.5 0.5 0.5 0.2 0.2 0.2 –56

Absolute GHG emissions from energy demand in Scope 2 according to the Greenhouse Gas Protocol11  2014–2024 in t CO2e

  2014 2016 2018 20202 20222 2024 Change since 2014 in %
Scope 2 GHG emissions total 1'038 1'765 1'927 1'981 2'810 2'683 158
Electricity purchased 33 34 34 275 288 278 754
District heating purchased 1'0063 1'732 1'893 1'706 2'522 2'405 139

Absolute GHG emissions from energy demand in Scope 3 according to the Greenhouse Gas Protocol12  2014–2024 in t CO2e

  2014 2016 2018 20202 20222 2024 Change since 2014 in %
Scope 3 GHG emissions total 2'102 2'644 2'795 2'668 3'146 2'956 41
Electricity purchased 1'028 1'060 1'073 1'110 1'160 1'120 9
Photovoltaik 0.1 2.8 3.0 6.3 14.0 12.0 16'610
District heating 751 1'200 1'227 1'116 1'561 1'497 99
Heating oil 56 53 58 41 24 8 –86
Gas 265 328 432 394 387 318 20
Wood 1.5 1.5 1.5 0.7 0.6 0.6 –56

Footnotes

1 The total energy demand and total heat values ​​differ from those in the Sustainability Report 2022, as heat recovery is no longer included.
2 Some values ​​from 2020 and 2022 differ from those in the Sustainability Report 2022 because the data for rental properties has improved.
3 The low heat demand in the reference year 2014 is due to high average temperatures in that year.
4 Although there was an increase in gas consumption in 2021 because additional rental space was needed in Schlieren and the laboratories there used gas for autoclaving, this increase is barely noticeable in 2022, as 2022 was an extremely warm year and dual-fuel systems switched to oil (see also the following footnote).
5 In 2022, there was an increase in oil consumption because, due to the energy shortage, UZH was encouraged to operate so-called dual-fuel plants with oil instead of gas.
6 The values ​​for total energy demand covered by renewable sources and heat energy differ from the values ​​in the Sustainability Report 2022, as heat recovery is no longer included.
7 Since 2019, the electricity mix used has been generated by European hydropower plants through the purchase of certificates.
8 Assumption: 50 percent of the energy from waste incineration is considered renewable, and 100 percent of the energy from wood.
9 The heat demand values ​​differ from the values ​​in the Sustainability Report 2022, as heat recovery is no longer included.
10 Scope 1 includes direct emissions resulting from the university's own fuel consumption, for example, heating oil for heating systems.
11 Scope 2 includes indirect GHG emissions that arise from the purchase of energy, for example, electricity or district heating, in the energy supply chain.
12 Scope 3 includes further indirect emissions caused by the purchase of consumer and capital goods or services (e.g., laboratory materials, air travel). In these cases, GHG emissions arise during the production, transport, and disposal of the goods or during the provision of the service.

 

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Developments in the area of fresh water

A combination of area and line charts; It shows UZH's freshwater consumption in cubic meters compared to the number of students and employees from 2008 to 2024. Freshwater consumption has steadily declined since records began, occasionally increasing but never returning to the initial level of 2008. The lines show that the number of students and employees continues to rise. It is remarkable that freshwater consumption is steadily declining despite this increase in population. Water consumption data for 2024 are not yet available, so the 2023 value was used.
Graphic: Melanie Lindner

In 2023, UZH consumed around 250'000 cubic meters of water. Fresh water consumption has fallen significantly since 2018 despite the growing number of employees and students. After a reduction due to the pandemic in 2021, consumption has been rising again since 2022.

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Source: Parts of this text were originally published in a similar form in German in the Sustainability Report 2021/2022 and have been continuously updated for this website.