Flights and Natural Gas

The big elephants in the room!

The greatest potential for a significant reduction in Empa's greenhouse gas-relevant emissions lies in aviation and the combustion of natural gas. For this reason the Directorate has decided to link these two problematic areas together.

The aim is to reduce air traffic by raising awareness of the consequences of flying. The flying person should overcome a certain hurdle in booking and paying for flights and compensate for the CO2 emissions of the flight. The resulting income is to be used specifically within Empa -> purchase of biogas.

The use of natural gas to generate heat causes direct CO2 emissions. These emissions can be significantly reduced by replacing fossil natural gas with biogas. The additional costs for biogas will be covered by the income from the internal CO2 tax on air travel, and thus remain cost-neutral.

Empa internal CO2 tax from air travel to replace natural gas with biogas

Decision: Since 01.01.2020, CO2 emissions caused by business flights are charged with a fee for all employees.

Amount: At CHF 96.- per tonne, the fee is equivalent to the fuel tax under Switzerland's current CO2 law.

Use: The fee will be used to purchase biogas certificates of origin. This has a direct leverage effect: emissions from air travel reduce Empa's internal emissions from the combustion of natural gas through substitution with biogas.

Effect: With the same level of air traffic as today, the proportion of biogas can be increased to about 40%, with a corresponding reduction in greenhouse gases. In addition, the fee encourages people to think about the necessity of flying, to use trains instead of air travel, and to motivate them to use modern means of communication.

Organisation: self-declaration of the departments. Fliers calculate the CO2 emissions of their flight e.g. here on and enter the result in the CO2 table (Excel template) of the department. The entry can also be made after the trip together with the submission of the expense form or checked at this opportunity. Closing annually at the end of June, in July each year the CO2 tables are sent to the sustainability delegate ( for evaluation. Afterwards, the finance department takes over the internal transfers from the departments, Real Estate Management coordinates the purchase of biogas in the amount of the income from the flight emissions.


Air travel regulation Empa

According to Empa regulations (André Schmid, mail 05.12.2019)

Air travel shall be limited to the minimum necessary. For shorter business trips to foreign countries close to the border, the offers of the railways must be taken into account. Regardless of the airline, the cheapest offer (taking into account the safety aspect) will be chosen. Bookings are made centrally via the travel department of the finance department. Air miles earned for business purposes should be used for business trips.

In practice, flight bookings are often made directly by the employees themselves or by the departments and no longer centrally via the finance department. When booking, please record the airport codes exactly in the CO2 accounting table and the financial statement (expenses). 

In the forthcoming 'Air Traffic Action Plan' of UVEK, business flights will be excluded with very few exceptions and minimum distances for permitted air travel will be specified (by destination and/or distance of at least approx. 600 km). 

Translated with (free version)


Excel-file for registering the flight data in the Empa labs.


Calculation tool from Myclimate for CO2-Emissions of flights.