A new steam plant that burns wood chips at Oak Ridge National Laboratory will save energy, reduce fossil fuel consumption, and cut greenhouse gas emissions, officials said Thursday.
The Central Biomass Steam Plant can produce 60,000 pounds of steam per hour. The steam is used to heat buildings during cold winter months and support research applications at ORNL.
The 21-megawatt plant is the flagship project in a $94 million, four-year-old Energy Savings Performance Contract with Johnson Controls Inc. of Milwaukee, Wis.
Officials had a dedication ceremony for the steam plant Thursday.
ORNL worked with Johnson Controls and Nexterra Energy Corporation to build the steam plant, which replaces a natural gas steam plant, allowing the lab to shut down four fossil fuel boilers.
The new plant can burn about 10 to 12 truckloads per day of local, renewable wood and wood products, or up to 77,000 tons of waste wood per year.
The wood chips are fed into a gasification chamber, where they reach temperatures of 1,500 to 1,800 degrees Fahrenheit. The chips do not burn in the oxygen-starved environment, and high-temperature combustible synthetic gas (or syngas) is extracted. The syngas moves into an oxidizer, where it is combined with oxygen and burns.
The flue gas is then routed to a boiler, where the steam is produced.
The exhaust gas is sent through electrostatic precipitators for cleaning before it is discharged to the atmosphere, “resulting in very low particulate emissions compared to those of natural gas and fuel oil,” according to information supplied by the lab.
The information said the biomass-fueled system will, when combined with two remaining boilers, reduce fossil fuel consumption by more than 70 percent and cut greenhouse gas emissions by more than 20,000 tons a year, the equivalent of between 6,000 and 9,000 cars per year, the information said.
The energy savings contract with Johnson Controls, which also includes digital metering and lighting and mechanical equipment upgrades, is expected to save an estimated $8. 5 million per year, the information said.