Iran’s largest biogas power plant in South Wastewater Treatment Plant in the capital generates 9 million kilowatts of power per year, a deputy of Tehran Province's Water and Wastewater Company said.
“The biogas power station, operational since 2013, curbs the emission of 200,000 tons of greenhouse gases, especially methane, annually by converting them to electricity,” Morteza Ehteshami was also quoted as saying by Mehr News Agency.
TPWWC has a long-term agreement with the Renewable Energy and Energy Efficiency Organization (Satba), based on which the latter is obliged to purchase the generated power for 15 years at an average price of 8 cents per kilowatt hour, he added.
Ehteshami noted that the generated electricity helps the wastewater treatment plant meet 70% of its requirement that is why when the whole city was adversely affected by frequent power outages in summer, South Wastewater Treatment Plant never stopped functioning.
The wastewater treatment facility processes close to 500,000 cubic meters of sewage per day and delivers it to farmers in Varamin Plain 40 km southeast of the capital.
According to the official, electricity generation from sewage processing will be launched in other Iranian metropolises, including Isfahan, Shiraz and Tabriz.
“The company is close to sealing contracts on setting up plants to produce power from methane in Isfahan, Shiraz and Tabriz,” he added.
Underscoring that electricity generation from sewage is one of the main goals of Energy Ministry and Abfa, Ehteshami said some of the wastewater treatment plants, such as the one in southern Tehran, are linked to combined heat and power plants, which can produce electricity from methane produced in the treatment process.
A biogas plant is a decentralized energy system that can lead to self-sufficiency in heat and power needs, as well as reduce environmental pollution.
Biogas is produced during an anaerobic digestion process. A biogas plant can convert animal manure, green plants, waste from agro industry and slaughterhouses into combustible gas.
It can be used in similar ways as natural gas in gas stoves, lamps or as fuel for engines. It consists of 50-75% methane, 25-45% carbon dioxide, 2-8% water vapor and traces of O2, N2, NH3, H2 and H2S.
Compare this with natural gas, which contains 80-90% methane. The energy content of the gas depends mainly on its methane content.
