Biomethane: Myths vs Facts

As with many complex topics, it’s easy to be confused about biomethane, which is also called ‘renewable natural gas’ or ‘RNG’ in North America. Where does biomethane/RNG come from? Does using it emit carbon dioxide? Is it good for the environment or not so good? Do the facilities where biomethane is produced cause pollution?

Anaergia has developed a complete set of technologies that help keep organic wastes from going into landfills and instead anaerobically digest these wastes to make biogas and biomethane (RNG). We can debunk some of the myths surrounding these fuels and their production.

Key points

• Biomethane (RNG) plants fight climate change by digesting organic waste diverted from landfills. This reduces emissions of methane (a potent greenhouse gas) from landfills and produces biogas, a renewable fuel.
• The EU aims to increase biomethane production capacity to 6.5 billion cubic meters per year, while North America, China, and Africa also have plans to boost biomethane output and increase energy security.
• Biomethane is derived from recently formed organic matter and does not contribute to climate change like fossil methane does. It is carbon-negative and prevents emissions that would otherwise occur if the organic waste were landfilled.

MYTH: Biomethane plants pollute.

FACTS: Biomethane plants do not pollute. On the contrary, these plants actually fight climate change! Biomethane facilities anaerobically digest food scraps, wastewater, and other organic wastes so these wastes don’t have to be landfilled. In landfills, these types of wastes create greenhouse gas emissions when they decompose. So digesting organic waste at biomethane plants reduces greenhouse gas emissions from landfills. In addition, these facilities produce renewable fuels that are used instead of fossil fuels. 

MYTH: The electric vehicle and biomethane transportation sectors are in competition.

FACTS: The electric vehicle and biomethane/RNG transportation sectors aren’t in competition. Rather, each sector takes advantage of the form of renewable energy that works best for that sector. For example, electric vehicles are optimal for short-distance and for smaller vehicles. EVs have a limited driving range and fewer options for recharging. On the other hand, biomethane is optimal for heavy-duty transportation–the tractor trailer trucks that haul goods long distances. In the EU, the use of biomethane in heavy-duty transportation is expected to help achieve the EU target of at least 14% of energy consumed in the transport sector by 2030.

MYTH: There isn’t enough renewable natural gas (biomethane) to make a difference in combatting climate change.

FACTS: Biomethane may be able to reduce global GHG emissions by 18-20% using various waste sources. Biogas can be used for electricity and heat, and biomethane can be fed into the natural gas pipeline grid and blended with natural gas to reduce emissions. Biomethane can be generated through waste sources like landfills and wastewater, and can also prevent methane emissions from manure management systems. Meeting greenhouse gas emissions reductions targets set by various states, provinces, and countries will depend in part on biomethane.

Figure 2 | 2050 biomethane production potential compared to 2021 combined biogas and biomethane production per European country – EBA Statistical Report 2022

Figure 3 | American Biogas Council, EPA LMOP 2020, Water Environment Federation “Enabling the Future,” EPA AgSTAR 2023, EPA “Anaerobic Digestion Facilities Processing Food Waste in the United States” January 2021.

MYTH: Using biomethane for fuel emits carbon dioxide, and it’s no different than burning fossil methane.

FACTS: Methane and biomethane are both gases that consist of the same molecule, CH4. But the source of this methane gas makes all the difference in whether it contributes to climate change. Most methane used today is a fossil energy source, meaning it was formed over millions of years as plants and animals died and were gradually buried by layers of rock. When society extracts and burns this methane, we release carbon dioxide (CO2) into the atmosphere from this carbon-based material that had been stored deep in the earth. This CO2 contributes to the greenhouse effect: the cause of global warming.

By contrast, biomethane is derived from organic matter that was formed a short time ago, not millions of years ago. That organic material—such as the plant material collected in green waste bins—has very only recently absorbed carbon dioxide from the atmosphere and when combusted it is not releasing any more carbon dioxide than it absorbed when growing. As a result, the balance between absorbed and released CO2 remains neutral.

What’s more, when we use organic waste to make biomethane, we prevent the emissions that would otherwise have occurred if the waste had decomposed in a landfill. That is why this fuel can be considered carbon-negative—because using it releases fewer greenhouse gases than would have been emitted had it been landfilled.

MYTH: There are few regulations of biomethane facilities.

FACTS: There are many regulations controlling the operation of biomethane facilities. Anaergia ensures compliance with the most stringent local environmental regulations at all of its plants and prevents the release of malodorous or polluting substances into the surrounding environment.

MYTH: Anaerobic digestion and biogas projects won’t help reduce the problems caused by livestock farms. People simply need to stop eating meat.

FACTS: Because consumer demand for meat is unlikely to be significantly curbed in the near future, it is crucial to capture the methane emissions that result from livestock farming and recover the available energy from manure. Biogas recovery systems result in an 85% reduction in methane emissions from dairy and swine operations. In 2021, manure-based anaerobic digesters reduced GHG emissions by 6.09 MMTCO2e, the equivalent of taking more than 1.35 million gasoline-powered cars off the road for a year. The total emissions reduction from these facilities from 2000-2021 was 54.4 MMTCO2e, the equivalent of taking more than 12 million cars off the road per year.

The U.S. EPA estimates that biogas recovery systems are technically feasible for more than 8,000 large dairy and hog operations. These farms could potentially generate nearly 16 million MWh per year and displace about 2,010 MWs of fossil fuel-fired generation.

In addition, the anaerobic manure digestion process reduces odors, protects water quality and improves soil health by reducing the need for chemical fertilizers. Biogas can be used as a direct fuel for heating, electricity, or vehicle fuel, and byproducts such as fertilizer.