A new biomass gasification plant at the Oak Ridge National Laboratory will burn wood waste from local sawmills to heat the complex, reducing fossil fuel use by 80 percent and greenhouse gas emissions by 23,000 metric tons a year.
The gasification plant built by Nexterra Systems converts waste biomass into a clean-burning syngas to produce 60,000 pounds an hour of saturated steam. The system replaces a natural gas steam plant and allows ORNL to shut down four fossil fuel-fired boilers. The plant, which has finished a 30-day endurance trial and third-party emissions tests, is now fully operational.
ORNL has been partially powered by steam since the 1940s. When the laboratory campus was first erected, steam was generated by coal and later shifted to natural gas.
The Nexterra plant uses three gasifiers to convert wood biomass to combustible syngas. The clean syngas is sent to an oxidizer, where it’s combined with oxygen, and then burned. The flue gas is directed to a boiler to produce steam, which is then distributed via pipeline to all ORNL campus buildings.
The laboratory uses SNCR, or selective non-catalytic reduction, to lessen NOx in the flue gas. Evaporative gas cooling further cleans the flue gas before it is released out the stack.
The plant is the flagship project in a $94 million energy savings performance contract with Johnson Controls. The contract, which includes the installation of advanced electric metering, compressed air cooling and efficient lighting, was among the first awarded under the US Department of Energy’s Transformation Energy Action Management Initiative.
This is the eighth energy-from-renewable waste projects completed by Nexterra. The company added an on-site biomass-fueled combined heat and power station at the University of British Columbia. The CHP generator there provides renewable energy and heat for campus buildings, and serves as a platform for bioenergy research.