Content we created for our client in the energy industry.

Key Takeaways

• RNG is a fast-growing alternative to conventional natural gas, with a market expected to reach $104 billion (USD) by 2032
• RNG is a biogas derived from the decomposition of organic matter, reducing GHG emissions
• RNG offers environmental and economic benefits, converting waste into valuable energy, mitigating waste management issues, and boosting economies
• Through the anaerobic digestion process, RNG can be created from landfills, dairy farms, and wastewater treatment plants

In the ongoing push to test and diversify feasible sources of energy, renewable natural gas (RNG) rises as one of the top economical alternative fuel sources. Many landfills, dairy farms, and wastewater treatment plants are seeking to understand the RNG production and infrastructure development process.

In this article, we’ll review:

• RNG and its benefits
• Production methods & sources
• Uses of RNG
• Integrating with current infrastructure
• Future of RNG
• Risk and Regulation

Introducing RNG

Renewable natural gas (RNG) is a reliable and ecologically friendly fuel source growing in popularity at a substantial rate within the energy industry. Last year, the RNG market was valued at $11.68 billion (USD) and is expected to grow to $104.74 (USD) billion by 2032.

RNG is a gaseous byproduct of fermented organic matter, most often currently utilized as a green alternative to conventional natural gas. RNG is considered to be a carbon-neutral fuel, i.e. one that has a net zero effect or better on carbon dioxide in the atmosphere. Depending on the production source or feedstock used to produce RNG, the associated carbon intensity of the production process can be significantly lower when compared to fossil fuels. Ultimately, this reduces GHG emissions and the impact of energy use on the environment.

RNG offers economic and environmental benefits

RNG also offers a unique opportunity to turn waste into wealth by converting organic waste such as farm animal manure and solid waste from landfills into energy, powering local economies. The U.S. alone produces over 250 million tons of waste, 140 million of which goes to landfills. RNG can make use of the organic material in this discarded waste.

RNG has economic benefits as well. RNG offers a (currently subsidized) cost-effective decarbonization and job market expansion within the energy sector, providing new opportunities in engineering, manufacturing, construction, maintenance, and operations. Financial incentives exist that encourage investors and corporations to purchase RNG, bringing them closer to meeting carbon emission reduction goals.

Producing RNG

RNG is produced from solid waste landfills, dairy farms, and wastewater treatment plants. Anaerobic digesters break down organic matter to create biogas. From there, RNG is processed and injected into natural gas transmission or distribution pipelines, or it can be used on-site where production occurs.

Anaerobic Digesters 

Using bacteria, anaerobic digesters break down organic waste (e.g., solid waste, wastewater biosolids, animal manure) to create methane that is transformed into RNG. This decomposition process occurs in a sealed reactor, which varies in shape and size to fit the site and the organic matter’s conditions. In addition to biogas, anaerobic digestion can produce another valuable product: digestate. Digestate is produced as both solid and liquid material, which can be used in or as fertilizer.

Anaerobic digesters are often coupled with equipment to process the biogas created into a transportable form, allowing it to be injected into existing natural gas pipeline systems and used interchangeably with natural gas.

Landfills

Landfills are managed disposal facilities for collected waste materials, coming from commercial, industrial, and residential areas. According to the U.S. EPA, these sites are the third largest source of manmade methane emissions in the nation. Rather than utilizing an anaerobic digester for the digestion process, biogas, also known as landfill gas (LFG), is created in the ground at landfills. LFG can then be upgraded to RNG.

Dairy Farms

Dairy farms are a substantial producer of methane emissions from farm animal manure. On many dairy farms, anaerobic digestors can be used to help reduce GHG emissions while supplying RNG to market.  

Wastewater Treatment Plants

Wastewater treatment plants are facilities that treat and remove harmful contaminants in wastewater. These plants can also produce biogas by digesting solids extracted during the wastewater treatment process.

Using RNG

Unlike other renewable alternatives such as wind and solar, RNG offers a reliable energy source, rain or shine, and it can be injected into existing natural gas systems. From there, RNG can be utilized to generate electricity, burned for heat, or used as transportation fuel. Like natural gas, RNG can fuel equipment, heaters, boilers, reciprocating engines, and gas turbines.

Integrating with Current Infrastructure

RNG takes advantage of existing pipelines and infrastructure, reducing the potential associated costs of development for new facilities. Unlike some other alternative fuels, RNG does not require system upgrades to be introduced or connected into larger utility systems. This allows for a seamless transition to RNG as an environmentally conscious alternative. This compatibility appeals to renewable energy investors and utilities alike.

Future of RNG

RNG is in high demand for its numerous benefits to the environment and economy. Areas with promising potential for RNG are those with the largest number of dairy farms or other production sites, including California, Wisconsin, Idaho, Michigan, and Texas, respectively. Of these, California has the greatest number of dairy farms while Texas has the most extensive natural gas pipeline network. With a rising opportunity for RNG within these areas, two of the largest natural gas utilities in Texas are currently seeking projects with landfills. Additionally, Wisconsin currently has emerged as a leader with the highest number of anaerobic digestors.

Regulations & Risks

Rules and regulations for RNG vary at the local, state, and federal levels. Some notable standards and regulations in place include renewable fuel standards, gas quality standards, land use and zoning regulations, the Energy Policy Act, and environmental regulations.

Conclusion

Analysis, regulation, measurement, and transportation of RNG will be key concerns as it becomes more prominent in the US energy mix.

Ultimately, RNG creates clean, reliable energy out of waste. RNG’s ability to enhance the job and decarbonization markets is likely to propel its prevalence in the future.