Againity supplies first-of-its-kind ORC application in Sweden
Sweden-based Organic Rankine Cycle (ORC) technology developer Againity AB has supplied the first-of-its-kind system for converting excess biogas into heat and electricity using an ORC at a Swedish municipal wastewater treatment plant (WWTP).
According to Againity, the idea behind the project is based on utilizing the energy in the excess biogas produced at the Slottshagen wastewater treatment plant (WWTP) in Norrköping. Operated by the municipality owned Norrköping Vatten och Avfall, the WWTP upgrades biogas to biomethane which is then used as fuel by the city buses.
However, gas production is higher than demand and previously the excess gas was flared at the WWTP. Instead, a new step is being installed whereby excess gas is used in a gas fired hot water boiler, with the hot water stored in an insulated buffer tank.
The ORC draws on the buffer tank producing electricity and in doing so cools the outgoing temperature of the water to around 50 degrees C. This is then used to heat the digesters at the WWTP. The ORC has an installed electrical capacity of 50 kW and the electricity will be used internally by the WWTP.