In early 2020, Western Disposal finalized an agreement with the City of Boulder for the purchase of renewable natural gas (RNG) generated at the city’s Water Resources Recovery Facility (WRRF). The RNG will be produced by a new system that will convert biogas, which is derived from the breakdown of organic matter in sewage, into RNG. The system came online in fall 2020 and its output will fuel up to 38 of Western’s 56 collection vehicles.
What is RNG?
During the decomposition process, organic matter emits methane gas, also referred to as biogas. RNG is a biogas-derived gas comprised primarily of methane after the biogas is cleaned and conditioned to remove most of its contaminants, carbon dioxide and nitrogen. This process brings the gas up to natural gas pipeline quality standards and it can then be mixed with, or used in place of, fossil-derived natural gas. The Coalition for Renewable Natural Gas describes RNG as “an ultra-clean, ultra-low carbon natural gas alternative”.
Why switch to fueling with RNG?
According to the U.S. EPA, natural gas is the cleanest option of all fossil fuels and replacing diesel with natural gas vehicle fuel, as Western Disposal has done with its fleet, reduces pollutant emissions and improves local air quality. So why take the next step to RNG?
RNG is renewable because its biogas feedstock is generated continuously, as opposed to fossil natural gas which is finite. Its production diversifies fuel supplies thus increasing local fuel security. Local economic benefits accrue through construction and maintenance of infrastructure, fuel production employment and RNG vehicle and fuel sales.
RNG provides additional benefit over fossil natural gas because it generally has a lower total carbon intensity (“CI”, also known as carbon footprint), after accounting for emissions from fuel production, transport and use. RNG’s CI is even lower when reduced CH4 emissions otherwise emitted from the organic waste used to produce the fuel are taken into account. The EPA has published data showing the average CI for RNG derived from wastewater recovery is 30 versus 80 for fossil CNG and 100 for diesel.
Western was one of the first waste haulers in Colorado to convert from diesel to compressed natural gas for its vehicle fleet, and our partnership with the City of Boulder to use its RNG is another step forward in reducing our carbon footprint. We’ve been serving Boulder and the surrounding communities for 50 years and are committed to being a key partner in helping to meet community climate goals.
Source credits: rngcoalition.com, epa.gov: An Overview of Renewable Natural Gas from Biogas, bouldercolorado.gov/water/wastewater-treatment
