State regulators have approved a plan by Roanoke Gas Co. to convert biogas from a sewage treatment plant into natural gas for distribution to customers in the region.
In an order issued Monday, the State Corporation Commission found that the joint project with the Western Virginia Water Authority is in the public interest.
"Roanoke Gas's project has the potential to achieve a rare combination of increasing local fuel supply, reducing greenhouse gas emissions, and increasing a utility's profit while also lowering rates," a SCC hearing examiner determined.
Plans call for the installation of a large piece of equipment at the authority's water treatment plant in Southeast Roanoke that will convert biogas created from the processing of sewage into natural gas.
"We are pleased to be the first gas utility in Virginia to receive Commission approval of a renewable natural gas project," Roanoke Gas said in a statement.
Equipment for the process is expected to be commissioned in the next four to six weeks.
Every day, the water authority's Roanoke Regional Water Pollution Control Plant receives about 37 million gallons of sanitary sewer from all of the Roanoke Valley jurisdictions.
The wastewater goes through an extensive treatment process that makes it safe to release into the Roanoke River. The solids that are left behind are moved to giant underground tanks where they are partially consumed by bacteria - similar to what happens in a residential septic tank - before eventually being distributed as free fertilizer for farms.
It is the second phase of the system, involving solid waste, that lends itself to the production of renewable natural gas.
As bacteria breaks down the organic material in an anaerobic digestion process, a biogas is produced that consists of 63% methane and 37% carbon dioxide.
Under the plan, that biogas will be pumped to a network of above-ground tanks, where an advanced membrane separation system will be used to refine it to pipeline-quality natural gas that will then be transported at high pressure to a nearby Roanoke Gas line.
In the past, the water authority had used some of the biogas as a fuel source, but ended up burning much of the methane off in flares designed to prevent more harmful emissions into the air.
Roanoke Gas says the facility will help insulate its approximately 63,000 customers from significant price increases by giving the company a locally produced supply that would not be subject to nationwide trends.