Energy from wastewater is CO2-free. Only the essential power for the heating pump must be considered when it comes to CO2. In districts, this electricity is often produced renewably locally, which means that no CO2 is emitted anyway. If we remember that the general electricity mix is getting greener every day, then energy from wastewater will be completely CO2-free in the medium term, even with the conventional electricity mix. At the moment, using energy from wastewater reduces CO2 emissions by 50 to 70 % compared with gas and oil.