The priorities were chosen based on the 2019 CO2 footprint analysis. Nikhef commissions a footprint analysis every year. Below are the results from 2019 through 2022. The number of trips in 2020 and 2021 has obviously decreased significantly due to COVID.
In 2019, Nikhef employees still traveled frequently by plane, causing 758 tons of CO2 equivalent. In the corona years 2020 and 2021, there was much less travel due to lockdowns and travel restrictions. By 2022, the restrictions had been largely lifted, but CO2 emissions were still only 263 tons, a third of the emissions from flying in 2019. Read the news item (8 June 2023).