What Is RNG and Where Does It Come From?

Renewable Energy / March 8, 2022

What is RNG, and where does it come from? As global waste is expected to grow 70% by 2050, renewable natural gas might fuel a greener future. By converting organic waste and harmful methane emissions into a fuel source, renewable natural gas effectively reduces greenhouse gas emissions that cause global warming.

Today we’ll go over how renewable natural gas is produced and its many benefits for the environment and the economy.

What is RNG?

Renewable natural gas, or RNG, is a carbon-neutral energy source that can be used interchangeably with natural gas derived from fossil fuels.

RNG comes from methane, biogas produced by the decomposition of organic matter. RNG projects then capture the methane and process it to meet purity standards. This results in a pipeline-quality gas that looks and acts just like conventional natural gas, making it a popular alternative to fossil fuels.

Renewable natural gas is an affordable, clean, and reliable waste-derived fuel that can power homes, businesses, and cars. Unlike conventional natural gas, renewable natural gas is a carbon-negative energy source that voids more emissions than it produces. Currently, RNG is mainly used as a transportation fuel, but it has many potential heating, electricity, and bio-product feedstock applications.

Where Does Renewable Natural Gas Come From?

The biogas that becomes renewable natural gas is sourced from many places, from wastewater treatment plants and other organic waste management operations to livestock farms and food production facilities.

Today, landfills comprise over 90 percent of renewable natural gas production. However, RNG can be made from all kinds of waste, such as:

Animal manure
Food waste
Compost
Wood waste
Wastewater sludge

How Is RNG Obtained and Produced?

Everyone produces waste, and eventually, that waste decays and releases methane emissions. These emissions are 80 times more potent than carbon dioxide over a 20-year period. Rather than allowing methane to enter the atmosphere, renewable natural gas production captures it and redirects it away from the environment to become a green energy source.

Although raw biogas can come from many sources, the basic process of converting it into renewable natural gas is the same. First, the organic waste is transferred to an oxygen-free, temperature-controlled environment. Then, when bacteria break down the waste during decomposition, it releases methane, along with carbon dioxide and other emissions, in a process known as anaerobic digestion.

The resulting biogas can replace traditional natural gas to generate heat and electricity, but it must be purified further for use as a transportation fuel. Purification starts with a cleaning process that removes contaminant gases, leaving only methane and carbon dioxide. Because it lowers the heating value of the gas, the carbon dioxide is then also removed.

The result is purified biogas, called biomethane or renewable natural gas, containing only methane and a small amount of nitrogen. After production, RNG can be used locally at the site where it was made or injected into natural gas distribution pipelines for transportation elsewhere.

Benefits of RNG

As a viable alternative to fossil fuels, renewable natural gas has many economic and environmental benefits.

Utilizes Existing Infrastructure

One of the biggest challenges in transitioning to renewable energy is adding or expanding infrastructure. In comparison, renewable natural gas can be used today in existing systems. In addition, because RNG acts like conventional natural gas, it can be transported through natural gas pipelines to utility companies to deliver to homes and businesses.

Because renewable natural gas is compatible with existing gas infrastructure, it is a cost-effective alternative to electrification and other alternative energy pursuits. However, it is important to note that building new fossil fuel-based infrastructure to expand RNG usage would counteract its environmental benefits.

Benefits Local Economies

Investing in renewable natural gas ultimately enables fuel diversification. In addition, economic benefits start at the local level through job creation and other business opportunities that come with the construction of RNG infrastructure.

A recent study found that California-based RNG production facilities would create 8.5 to 11.2 jobs per million diesel gallon equivalent of transportation fuel produced. This is in contrast to 1.6 jobs per million diesel gallon equivalent from fossil fuel refineries. RNG projects also can gain access to a secure long-term fuel source to run their vehicle fleets, rather than contending with the volatile fossil fuel market.

Improves Local Air Quality

Replacing fossil fuels with renewable natural gas significantly reduces emissions of nitrogen oxides, which is the primary component of smog, or black carbon. In addition, because RNG is composed mainly of methane, it contains few constituents like propane, butane, or other trace hydrocarbons that contribute to air pollution.

Implementing RNG at scale in heavy-duty trucks would also immediately benefit low-income, predominantly minority areas that suffer the most from exposure to diesel exhaust.

Reduces Greenhouse Gas Emissions

As a carbon-neutral fuel, renewable natural gas does not release any carbon dioxide into the atmosphere. In fact, RNG is often produced from organic waste that would otherwise create methane emissions, providing a negative carbon impact overall.

Switching to RNG can reduce greenhouse gas emissions by eliminating the emissions produced using conventional natural gas like compressed natural gas (CNG) and liquefied natural gas (LNG). Furthermore, recent research shows that by replacing less than 20% of the conventional natural gas supply with renewable natural gas, the reduced greenhouse gas emissions would be equivalent to converting 100% of buildings to electric-only energy by 2030.

Choose FASTECH For All Your Alternative Fueling Projects

Renewable natural gas is a versatile alternative fuel source that can be easily used with existing energy infrastructure to deliver carbon-negative fuel to homes and businesses. From improved air quality to reduced greenhouse gas emissions, RNG holds endless potential for the future of renewable energy.

As the leading provider of end-to-end energy solutions, FASTECH is committed to fighting climate change by expanding the renewable fuels industry. With over two decades of experience in the energy industry, we combine innovative engineering solutions with unparalleled renewable expertise to deliver cutting-edge, sustainable energy sources.