Cummins Executive Says Renewable Natural Gas Has Potential and Challenges

Renewable natural gas from sources like wastewater treatment plants has significant room to grow as a carbon-neutral or even carbon-negative fuel source that is not a fossil fuel.

But in an article on global power leader Cummins Inc.’s website, Puneet Singh Jhawar, General Manager of the company’s Global Natural Gas business, says some key challenges remain.

Renewable natural gas, commonly known as RNG, is made from biogas, which is the product of a biological process known as anaerobic fermentation. It’s obtained when the undesirable components of biogas, such as carbon dioxide and nitrogen, are removed.

In many cases, RNG is made at facilities that generate a feedstock as a by-product of their operations. Wastewater treatment plants and dairy farms, for example, can produce RNG using sewage sludge and manure, respectively. Another option is to process food waste into biogas and RNG.

The Cummins executive says the Argonne National Laboratory’s database captures the total annual RNG production capacity in the United States. In 2021, production capacity was about 660 million gallons of gasoline equivalents (GGE). That’s a 20% increase compared to the previous year.

That is a lot of RNG, but still just a fraction – about 3% – of the total natural gas consumption each year in the country, beyond solely vehicles’ consumption.

It may be possible to increase the production of RNG in the United States—and in other countries—by orders of magnitude. According to a study quoted by the American Gas Association, the United States could have the potential to produce up to 36 billion GGE equivalent of RNG each year by 2040.

If all of that was used in transportation applications, that would be enough to fuel about two-thirds of all diesel vehicles in the country.

Producing RNG is only part of the challenge to making more available, Singh Jhawar writes. RNG also needs to be transported and distributed to end-users.

Compared to other alternative fuels, RNG has many advantages. RNG is, chemically speaking, nearly identical to natural gas obtained from fossil resources. So RNG can be injected into the existing natural gas transportation and distribution infrastructure, as long as it meets each pipeline’s specifications.

However, the network of natural gas fueling stations is less dense than the one for gasoline or diesel. There are about 1,500 public and private stations dispending compressed natural gas in the United States, compared to over 150,000 gas stations with gasoline or diesel.

Most of the RNG supply is sent to states with low carbon fuel credits for natural gas.

To learn more, check out the full article at the Cummins’ website.