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Sustained picture of energy consumption at Leiden University

The energy and water consumption and CO2 footprint of all buildings at Leiden University can now be seen on its new Duurzaam in Beeld website. ‘We do a lot about sustainability,’ says Jeroen Waijenberg, Sustainability and Energy Coordinator at the University’s Real Estate Directorate. ‘But our efforts mostly go unnoticed.’

Compare buildings

Click on a University building on the Duurzaam in Beeld website and a photo of the building will appear together with its gas, electricity and water consumption, its CO2 emissions and the annual gas and electricity consumption per square metre of gross floor area (‘GJ-primair per m2 BVO’). This highlights differences between buildings.

Jeroen Waijenberg.


In January, the figures for 2016 replaced those for 2015. This could be done fairly soon in the year because the Erbis measuring system loads new consumption and emission figures each month. To view the details, hover over a building and click on ‘Go to the dashboard’, which appears under the building’s name. This takes you to a page with graphs that show the building’s gas, electricity and water consumption over the last 12 months together with its CO2 footprint and a benchmark. The ‘Explain Benchmark’ link shows which buildings are comparable, for instance the Huygens and Silvius Lab, or Lipsius and KOG. The benchmark is the average of these comparable buildings.

Aspects of sustainability

Leiden University uses the BREEAM method, which Waijenberg explains is an international method used to assess the sustainability of buildings and issue them with a rating. Almost all the University buildings qualify as ‘buildings in use’. The BREEAM-NL In-Use label assesses buildings on the aspects of Building (asset), Management and Use. More specifically, it assesses the aspects of management, health and welfare, energy, transport, water, materials, waste, land use and ecology, and pollution. The type of building that is being assessed is also relevant. It will be more difficult for a historical building to attain a high score on all these aspects than for a brand-new building that has been constructed with sustainability in mind. This means that an inventory must first be made of the building (baseline measurement). Its performance over time (in percentages) is then translated into a maximum of five stars.

Site expansion

Duurzaam in Beeld is just a beginning to gain insight into how sustainable the University is. ‘In future, the site could be expanded to include more data, for instance about the energy produced by the solar panels that are going to be installed on various roofs at the University,’ says Waijenberg.



Leiden University is the first university in the Netherlands to register its precise energy consumption and CO2 footprint per building and publish the data online. The energy monitoring system used for this, Erbis, was devised by Van Beek Ingenieurs and developed in close collaboration with the University. The aim is to find out and monitor the University’s energy consumption.


The data is also needed for BREEAM, an international tool used to monitor the sustainability of buildings at various stages and issue a BREEAM rating. There are BREEAM ratings for Area Development, New Construction and Renovation, In-Use, and Demolition and Disassembly. The possible ratings are: Outstanding, Excellent, Very Good, Good and Pass.

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