According to the official calculation by the electricity association VSE, the Swiss consumer mix electricity causes around 110 grams of CO2 per kilowatt-hour at the socket. Those who consume solar power from their own roof themselves instead of drawing grid power avoid these emissions for the corresponding amount of electricity. This page discloses the calculation methodology instead of claiming a fixed «CO2 savings per kWp». (As of: September 2026)
Key points in brief
- The reference value is the official CO2 content of the Swiss consumer mix (basis 2020–2022): around 110 g CO2 per kWh at the socket.
- This value is calculated periodically by the VSE according to a methodology co-developed by the SFOE (basis: SFOE/Treeze).
- The CO2 savings can be derived as a simple multiplication: self-consumed kWh times 110 g CO2 – only for the portion actually consumed by oneself.
- A fixed number such as «X tonnes of CO2 per kWp and year» is deliberately not given because the self-consumption share varies greatly.
How high is the official CO2 content of Swiss grid power?
| Metric | Value | Source |
|---|---|---|
| CO2 content of Swiss consumer mix (basis 2020–2022) | around 110 g CO2/kWh at the socket | VSE (strom.ch), SFOE/Treeze methodology |
As of: September 2026. The value refers to the average consumer mix at the socket, and is recalculated periodically.
How do you calculate the CO2 savings of a specific solar system transparently?
The calculation consists of two steps: 1. Determine the amount of self-consumed electricity (kWh per year) from the monitoring. 2. Multiply this amount by the current emission factor (around 110 g CO2/kWh). The manufacturing emissions of the solar system itself and the amount of electricity fed into the grid and not self-consumed are deliberately not included.
In consultations, we often ask customers to realistically estimate the self-consumption share of their planned solar system before making a statement about CO2.
Frequently asked questions
Why does this page not name a fixed CO2 saving per kWp?
Because the self-consumption share differs greatly depending on the household and the manufacturing emissions of the solar system itself are deliberately not included here.
Where does the value of 110 grams of CO2 per kilowatt-hour come from?
From the industry organisation VSE, which calculates the CO2 content of the Swiss consumer mix using a methodology developed with the SFOE and Treeze.
Are the manufacturing emissions of the solar modules included in this calculation?
No, deliberately not. This page only describes the avoidance of emissions during operation, not the complete life cycle assessment.
Does the emission factor change from year to year?
Yes, it is recalculated periodically based on current generation and trading data.
How much CO2 could your planned solar system save?
We calculate the realistic self-consumption share for your specific project.
Sources: VSE (strom.ch), «CO2 content of the Swiss electricity mix» (SFOE/Treeze methodology 2021).
Last updated: 18 September 2026 · Contact for questions on methodology: ecoEn editorial team
