RNG 101: the basics of Renewable Natural Gas
Northern Colorado Clean Cities recently interviewed CGRS and City of Longmont, Colorado, representatives about the ins and outs of constructing a system that converts biogas at a wastewater treatment plant to Renewable Natural Gas (RNG). The goal: provide useful information about the decision-making and construction processes so other jurisdictions can determine if a similar project is right for their facilities and their communities. The following article is based on the content of those interviews.
“Basically it offsets the greenhouse gas, obviously, and we’re using it, so it helps with carbon impact,” Kahler said. “If you take into consideration the amount of carbon produced by a diesel-burning vehicle and you eliminate that diesel-burning vehicle and start burning renewable natural gas, it can be carbon negative.”
He used Waste Services fleets, which stop and start often, as an example of how CNG vehicles can have a visible impact on a community’s environment.
“Every time they step on the throttle on the old trash trucks, you would see black puffs of smoke coming out of the exhaust,” he said. “It’s dirty, it’s not appealing.”
Gage noted some WWTP operators treat their biogas to a lower-quality RNG to fuel combustion engines that provide electricity and heat.
If RNG is treated to meet higher specifications, the jurisdiction can inject it into a pipeline where other end users across the country can access it, Kahler said.
In Longmont’s case, the ability to fund the RNG system and its fleet replacement cycle aligned so the City could not only build an RNG system at its WWTP, but also pipe it to a new Waste Services facility where it is turned into CNG and fuels the City’s new CNG trucks.