Climate change calls for fast and drastic measures. The EU therefore aims to be carbon neutral by 2050, following the lead of the Paris Climate Agreement. This means:

• almost complete transition to renewable energy
• no more fossil energy
• greatly reduced energy demand

The Netherlands also intends to become independent of Russian gas, in view of the sharply rising gas prices due to the war in Ukraine. This makes the need for a clear, effective energy policy even more urgent.

Therefore:

• We have produced a Roadmap to carbon-neutral campuses, giving details of how the University will have achieved a 65% carbon reduction in 2030 compared with 1990.
• We will carry out renovation and construction when this is a natural choice: when a building (or part of a building) has reached the end of its life cycle.
• We will further save natural gas by setting the heating to a maximum of 19° C in winter, and reducing the cooling by 2° C in summer. Also read: Leiden University turns the heating down by two degrees
• We will also investigate whether we can:
  • have the heating on for a shorter time in certain buildings (e.g. only between 9:00 and 17:00 hours)
  • reduce the high level of night-time electricity consumption
  • heat just one building per campus in the evening and at night
• We are also involving staff and students in energy saving via the Leiden University is making the switch too campaign.

The Energy Transition Monitor (in Dutch) shows the energy consumption of each faculty, service department and building.

To achieve the energy-saving goals, we need more than the Roadmap to carbon-neutral campuses, which only explains how we plan to make our buildings Paris Proof and says nothing about the role of users. This role is important, however, because the use of rooms and equipment accounts for a growing share of the University’s energy consumption: after a building has been renovated (including e.g. insulation), the building-related energy share decreases considerably.

Out of all users, researchers in laboratories require the most energy: up to 70% of the total consumption. This is only logical, given the intensive energy consumption of advanced research equipment. Nevertheless, energy savings can also be achieved here, by using this equipment more consciously. It is important to make changes in behaviour and systems within faculties. For example, laboratories could join the international programme of LEAF, the Laboratory Efficiency Assessment Framework.

Leiden University is making the switch too

We will only achieve drastic energy reduction on the campuses if all users recognise the need for this and are willing to be economical in using energy.

Through the Leiden University is making the switch campaign we show our staff and students possible ways to do this.

Solar panels

In 2021, around 1.5% of Leiden University’s electricity consumption came from self-generated electricity. This required more than 3,000 solar panels on eight University buildings. Most of these (1,250 panels) are located on the roof of the Lecture Hall Building. In the next few years we are planning to further increase the number of solar panels and expect to generate 1.7 million kWh in 2024 (more than double the present amount), which is equivalent to the electricity consumption of nearly 625 households.

Sustainable thermal energy storage in the ground

One of the methods used by Leiden University for sustainable heating and cooling of buildings is thermal energy storage (TES), also known as the open-loop ground source energy system. This technique utilises the residual heat from the summer in the winter. TES is already used on the Leiden Bio Science Park campus and Campus The Hague, and will also become available for the Humanities Campus in 2023.

How thermal energy storage works

The investment costs for a TES system are high, it can take a few years for the system to become stable and there are many rules that must be obeyed. TES is particularly cost-effective for renovated buildings, because the sources have a much lower initial temperature and therefore underfloor or ceiling heating (over larger areas) is needed to heat a building in winter.

District heating

Another method used by Leiden University for sustainable heating of buildings is district heating: a network of hot water pipes conveying residual heat from industry.

This kind of heating network can come from a variety of sources, often still from power plants with a ‘combined heat and power’ (or ‘cogeneration’) connection. These plants generate electricity – frequently using coke or gas – and the released heat then goes into the district network. Heating networks are currently making urgent changes to increase their share of sustainable, non-fossil sources.

We are investigating whether the Pieter de la Court Building and the Sylvius Building could in the future be connected to the long-anticipated heat pipeline from the Port of Rotterdam.

Electricity

To satisfy the total demand for electricity, Leiden University buys from a large energy supplier. This is done in conjunction with, among others, the LUMC and other parties in the healthcare sector; reliability of supply is therefore the most important condition. Since 2017, however, Leiden University has made sure that this electricity is guaranteed to come from Dutch wind turbines, via Guarantees of Origin.

Natural gas

Leiden University mainly uses natural gas for hot water and building heating. In 2021 the University consumed a total of around 3.7 million m³  of natural gas (equivalent to the consumption of around 3,000 households per year).

Thermostat set at 19

Since May 2022, Leiden University has reduced the setting for heating in buildings by 2 degrees. This means that our buildings are 19° C in winter, and in summer they stay closer to the outdoor temperature (with slightly less cooling). This should reduce natural gas use by a further 6%, amounting to around 100,000 m³  of natural gas per year (comparable to the consumption of 80 households). As a result of all the building renovations, Leiden University will have halved the natural gas consumption in 2030 compared with 2019. We are doing everything possible to become natural gas-free even sooner.

Greening credits

As our aim is to reduce our carbon footprint and hence our environmental impact, we compensate for our natural gas consumption each year by purchasing Voluntary Emission Reductions (VERs). These ‘greening credits’ finance projects designed to reduce CO2 emissions, such as capture and storage of manure gases.