Abstract
The European Parliament’s climate and energy policy, which aims to cut greenhouse gas emissions by 2030 considerably, imposes on Member States the duty to develop National Action Plans (NAPs), which determine the percentage of renewable energy sources (RES) in gross energy consumption. Poland assumed a percentage of renewable energy sources in gross energy consumption of 21−23% in the NREAP. In 2020, Poland’s utilisation of renewable energy sources was 16.2% (22nd among EU nations), which was lower than the European average. The municipal sector, particularly sewage treatment facilities, can undoubtedly contribute to an increase in renewable energy generation and utilisation. Wastewater and sewage sludge are excellent sources of heat and energy in the methane fermentation process, and the sewage treatment plant area is perfect for solar panel installation. The article is a case study that presents the possibility of decreasing CO2 emissions from wastewater treatment facilities by 45,000 PE due to using renewable energy sources such as photovoltaics and cogeneration. The average monthly CO2 emission reduced from 68,905 kg CO2/ month to 37,385 kg CO2/month with the adoption of renewable energy sources.