Energy production in the municipality of Örebro
Detailed description of the Good Practice
The city waste disposal site, Atleverket, produces a continuous flow of biogas all year round. The methane content is around 50% CH4 and the energy content accumulates to around 15 GWh/year. At the waste water treatment plant (WWTP), on the east side of the city, two 3000 m3 (106 000 ft3) digesters produce methane gas, biogas, at a typical 63% CH4 and a rate of 250-600 m3/hour. The production of methane in the plant equals to 15 GWh of energy/year. Part of the gas is then sold to nearby industries and the city hospital where steam is made and thereby reduces the need of fossile fuels.
The WWTP handles waste from food- and beverages industries in the vicinity of Örebro. This material is an excellent organic raw material to make methane gas out of. Without this external organic material the energy production of the digesters would only reach around 10 GWh. The total capacity of the digesters and gas system is about 20 GWh.
Objectives of the Good Practice
At the end of 2007, Örebro started its production of vehicle gas. The machinery was erected adjacent to the existing biogas production part of the plant. Out of the biogas (63% CH4) the plant has a total capacity of around 150 000 m3 (5,3 million ft3) of vehicle gas/month. The present production is only 40 000 m3 (1,4 million ft3) of vehicle gas/month (>97% CH4). This is due to the fact that we don’t have enough vehicles running on gas in the city yet.
The sludge from the waste water treatment plant is spread on energy forests as fertilizers. Energy forests are then used as fuel in a furnace at Eon and other power plants. The sludge contributes ~14 GWh/year of energy for the furnaces.
More Details of the Good Practice
Örebro municipality Climate Office