Over the course of the last decade, Western Disposal has transitioned its fleet fuel from diesel to compressed natural gas (CNG). CNG is a cleaner alternative emitting an estimated 20% fewer smog-forming pollutants and greenhouse gas emissions than its diesel equivalent.
Beginning in October of this year, Western began fueling 100% of its fleet with renewable natural gas (RNG). CNG and RNG are chemically identical; they can be blended in the delivery pipeline and a vehicle that runs on fossil natural gas requires no modification to run on renewable natural gas. So why make the switch? Despite their interchangeable nature, renewable natural gas outshines fossil natural gas when it comes to environmental benefits.
What is Renewable Natural Gas and Where Does It Come From?
RNG is a term used to describe biogas that has been upgraded for use in place of fossil natural gas. In the U.S., biogas used to produce RNG comes from a variety of sources, including municipal solid waste landfills, digesters at wastewater treatment plants, livestock farms, food production facilities, and organic waste management operations. Depending on the source, biogas contains 40-60% methane, the remainder is comprised of CO2 and other trace-level contaminants.
Upgrading biogas involves conditioning to reduce CO2 and contaminants and increasing the methane to 90+% bringing it to a level suitable as an alternative to fossil natural gas. RNG can be used locally at the site where it is created, or it can be injected into natural gas transmission or distribution pipelines. Currently, RNG is used primarily as a transportation fuel and plays an increasing role in the production of electricity.
Lower Carbon Energy Source
Recycling biogas through the generation of RNG avoids emissions of methane. According to the EPA, because methane is both a powerful greenhouse gas and short-lived compared to carbon dioxide, capturing and recovering methane from biogas can achieve near-term beneficial impacts on greenhouse gas emissions. In addition, using RNG as an alternative fuel displaces the fossil natural gas that would have been consumed, thereby reducing CO2 emissions. Calculated in terms of carbon intensity (CI), a measure of greenhouse gas emissions associated with producing, distributing, and consuming a fuel, RNG’s CI ranges from -200 to 30 (depending on the source) vs. 80 for fossil natural gas.
Other Benefits of Renewable Natural Gas
In addition to lower carbon intensity, renewable natural gas:
- Converts what would otherwise be waste into a valuable product
- Uses readily available feedstocks to produce a steady supply of domestic, renewable energy
- Is easily accessible to users through existing natural gas infrastructure
- Enhances fuel diversity, reducing supply volatility and dependence on foreign sources
- Creates domestic jobs in an emerging and growing industry
Western Disposal’s fleet of 65 collection vehicles logs more than 1.5 million miles annually and reducing the climate impact of those miles is among our top priorities. Since 2020, we have fueled 50% of our fleet with renewable natural gas sourced from the City of Boulder’s Water Resource Recovery Facility. This additional RNG supply will be purchased through a variety of sources. We are excited to complete this transition to a cleaner, more sustainable fuel source.
Sources: U.S. Department of Energy, U.S. Environmental Protection Agency