Personal footprint:
How are emissions in the "living and energy" sector calculated?
The energy consumption of a building depends on factors such as size, insulation, ambient temperature, room temperature, ventilation and utilisation. In order to compare the energy consumption of buildings, the heating energy per area and year is used as a reference value.
For our footprint calculator, we differentiate according to the common building standards in Switzerland. The energy consumption per year and square metre varies between 0 and 180 kWh, depending on the building standard. Detailed information on this is provided on the energie.ch website.
The type of heating also plays a key role, as it can be based on fossil fuels or come from renewable sources. The greenhouse gas emissions emitted by the heating system therefore depend on the heating energy consumed and the type of heating system. We use emission factors from the FOEN and the IPCC for the conversion into CO₂ equivalents (emissions).
Most people are aware of their electricity consumption, as we receive this information directly on the bill, which often comes separately. You will also find the electricity product on the bill. Electricity consumption in households varies depending on the type of household (apartments, houses) and the number of people. According to the Swiss Federal Statistical Office (SFOE, 2022), an average of 5,066 kWh is consumed per household per year in Switzerland.
In Switzerland, we have a relatively low-emission electricity mix compared to other countries. This is because we can generate a lot of energy from our water resources. We define renewable energy as all energy that comes from wind, sun or water.
How are flight emissions calculated?
When calculating the emissions resulting from a flight, the distance travelled and the selected flight class are decisive factors. The influence of the flight class is due to the fact that more space is taken up per person in Business Class and therefore fewer people can travel in an aircraft than in Economy Class. Accordingly, more emissions are caused per person in Business Class.
For the personal footprint, our calculator allows you to specify how many intercontinental or European flights were taken in which class. We work with average values so that we can calculate the distance travelled.
The emission factors we use to calculate the emissions per passenger kilometre are constantly updated and come from Defra (Department for Environment, Food & Rural Affairs, UK) and treeze. We use an RFI factor (Radiative Forcing Index) of 2.
How are the emissions in the "mobility" sector calculated?
In the case of emissions from private cars, the distance travelled, the average occupancy of the car and the vehicle type are relevant.
An average occupancy rate of 1.12 persons is assumed for all cars, which corresponds to the average in Switzerland.
For journeys with electric or hybrid vehicles, the consumption of the Swiss electricity mix is assumed.
Emission factors from mobitool per passenger kilometre are used to calculate emissions. Corresponding emission factors from the mobitool are also used to calculate the distance travelled by motorbike or public transport.
How are the emissions in the "nutrition" area calculated?
Our diet has a significant impact on our personal footprint. In general, animal-based products have a higher carbon footprint than plant-based products.
The data that provides us with the annual greenhouse gas emissions based on dietary style comes from a study by ESU-services entitled "Eco-profile of dietary styles".
On average, transport, distribution and packaging contribute around a fifth of the greenhouse gas footprint of all diets.
How are emissions in the "consumption" sector calculated?
In Switzerland, a relatively large amount of money is spent on private consumption. Most of the products and services we consume also have a CO₂ footprint.
Our CO₂ calculator takes into account the emissions that occur abroad as well as domestic emissions. Therefore the so-called "import emissions" are also included in the personal CO₂ footprint.
In order to calculate the greenhouse gas emissions of our consumer behaviour, we collect information on how much money is spent per month on the various items. This data is calculated using an average emission factor per category, which is based on data from the Federal Statistical Office (FSO, 2019).
Where do the emissions in the "Public services" sector come from?
As the emissions that we all cause together in Switzerland via the public sector are not yet reflected in the personal footprint, they are added to each carbon footprint.
The greenhouse gas emissions per person are calculated by dividing the total greenhouse gas emissions of the public sector by the number of inhabitants in Switzerland.