Biogas and Renewable Natural Gas Production: The Benefits and the Risks

Considerations for Achieving a Sustainable Future Through Safe Design and Operation

What is biogas and how is it produced? 

Each year, the U.S. generates nearly 70 million tons of organic waste, ranging from food scraps and sewage to agricultural byproducts. In the absence of oxygen, bacteria break down this biomass to produce biogas — a renewable, eco-friendly energy source composed primarily of methane and carbon dioxide, along with trace gases like hydrogen sulfide. 

Why is biogas beneficial?

Organic waste naturally decomposes, releasing greenhouse gases that can harm the environment if left unchecked. By capturing these gases during the decay process, biogas production reduces harmful emissions and creates a sustainable energy source. This approach not only mitigates environmental impact but also provides a practical way to power machinery and manage waste more responsibly. 

What can biogas be used for?

Compressed biogas can fuel vehicles, while biogas upgraded to natural gas standards — known as biomethane or renewable natural gas (RNG) — can serve as a cleaner alternative to conventional natural gas. RNG can be used for things like home cooking and heating offering versatile applications for a sustainable energy future. 

How can biogas be upgraded to produced RNG?

RNG production requires specialized facilities that transform biomass into biogas through anaerobic digestion. These facilities purify and upgrade the biogas to meet natural gas standards, often including steps like pretreatment, purification, and sometimes liquefaction. Once refined, RNG can be injected into natural gas pipelines or used to fuel RNG-powered vehicles, seamlessly integrating into existing energy infrastructure. 

Is RNG production hazardous?

While RNG offers many benefits, the production process does come with risks. RNG facilities handle flammable and toxic materials, and since these plants are often small, they may not fall under OSHA PSM 1910.119 regulations, which apply to facilities containing 10,000 lbs. or more of flammable substances. 

When dealing with flammable and toxic materials, however, it’s crucial to recognize the potential hazards and risks associated with the process regardless of formal requirements. 

What are some examples of the risk associated with RNG production?

RNG production presents several potential hazards. Here are a few examples previous incidents and studies we’ve conducted at BakerRisk:  

1. An explosion in the Anaerobic Digester (AD).
2. An overpressure or vacuum within the Animal Waste AD, causing the release of toxic and flammable material into the atmosphere.
3. An explosion in an  enclosed Compressor Building.

Our white paper, “Renewable Natural Gas: considerations for the safe design and operation for an innovative process for achieving a sustainable future” explores these risks in detail and provides examples of safeguards and mitigation strategies to minimize potential injuries or fatalities. 

Safe RNG production starts with expertise

At BakerRisk, we specialize in helping clients identify, assess, and mitigate the hazards associated with a variety of industries, including RNG production. For additional information on biogas and other industry hazards, visit our BakerRisk Learning Center and discover the resources you need for proper risk management. 

“Renewable Natural Gas,” United States Environmental Protection Agency, November 6, 2024, https://www.epa.gov/lmop/renewable-natural-gas. 

“Renewable Natural Gas Production,” United States Department of Energy, https://afdc.energy.gov/fuels/natural-gas-renewable. 

“RNG plant: Technologies, Production Process, and Maintenance,” AB Group, https://www.gruppoab.com/en-us/blog/rng-plant-technologies-production-process-and-maintenance/. 

Tanikawa, S., “Fact Sheet | Biogas: Converting Waste to Energy,” Environmental and Energy Study Institute, October 13, 2017, https://www.eesi.org/papers/view/fact-sheet-biogasconverting-waste-to-energy.