As the different industries race to find sustainable yet efficient energy sources, biomethane stands out as one of the most interesting alternatives.
Find out what is biomethane exactly, what are the differences between it and biogas, and the right equipment to handle liquid biomethane.
What is biomethane?
Biomethane is methane that has been obtained from processing biomass.
Also known as renewable natural gas (RNG) or Sustainable Natural Gas (SNG), it presents similarities to natural gas but is considered a renewable source, as it can be endlessly obtained from organic matter in the process known as bio methanation.
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Biogas and biomethane: what’s the difference?
Simply put, biomethane is an upgraded form of biogas, generated through the anaerobic digestion process.
On the one hand, biogas is obtained at solid waste landfills when organic matter is broken down by bacteria. The result is a mixture of gasses that may contain between 40 or 70% methane and other compounds (30–40 % CO2, 2–8 % of H2O and other compounds and particulates). Other potential sources for biogas include sludge from wastewater plants, livestock waste and arable waste, among others.
On the other hand, biomethane is obtained by upgrading biogas, so that the process helps remove carbon dioxide, water vapors and other compounds. The result is a compound where the methane proporcion is higher, typically similar to natural gas of fossil origin.
Production pathways for biomethane
Today, the main technique to obtain biomethane is the upgrading of biogas. There are a number of potential pathways in order to do so:
- Water washing
- Chemical absorption
- Pressure swing adsorption (PSA)
- Membrane separation
- Cryogenic technologies
Additionally, some operators are experimenting with a second pathway for obtaining biomethane, which includes the thermal gasification of solid biomass, which is then put through bio methanation processes. In this case, high temperatures and pressure are used in low-oxygen environments so that biomass is broken down into a mixture of gasses. Then, a reaction is produced to produce methane, while other undesired compounds are eliminated.
How is biomethane stored?
Achieving an efficient storage and transportation of this gas has been crucial for industries looking to make the most of this renewable source of energy.
Today, the conversion of biomethane into liquid biomethane (LBM) is considered one of the most optimized methods for its storage.
Through this process, long-term storage and transportation are facilitated for two main reasons:
- Liquid biomethane presents a lower volume, so that larger quantities can be stored in less space compared to the gaseous form of biomethane. In other words, it helps save space. Super-insulated cryogenic vessels are used for this purpose.
- It can be transported using for cryogenic substances, following similar processes as the transportation of Liquefied Natural Gas (LNG).
- Super-insulated pipe systems can also be adopted for the transportation of liquid biomethane between two cold points.
Industrial applications of biomethane
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This gas is becoming a key source of energy as private and public organizations endorse the search for more sustainable alternatives. As such, it is transformed into electricity and heat as a more efficient source than biogas.
It thus facilitates a number of alternatives and industrial applications:
- Transportation fuel, replacing compressed natural gas, diesel and liquid natural gas (specifications for this process are to be found in UNE-EN 16723-2)
- Generation of steam and heat
- Combined heat and power production
- Injection into the natural gas grid. In this case, certain requirements must be observed, which are included in UNE-EN 16723-1
Keep reading: The value of technical gases for industrial production
Benefits of biomethane
Cut down on harmful emissions
Biomethane represents a more environmentally-friendly alternative source of energy as it minimizes CO2 emissions on several fronts. Firstly, it helps control emissions that are produced naturally from organic residues, which then are released into the atmosphere; secondly, it helps move away from fossil fuels used as energy; finally, through its production, it contributes to return organic carbon back into the soil, so that other less sustainable fertilizers can be avoided.
Reduce dependency on importing fossil fuels
Today, many countries are dependent on importing fossil fuels that are not immediately available to them. Biomethane can provide significant relief in this area.
The European Biogas Association paints a clear picture on the importance of biomethane regarding the building of less dependent economies when it comes to fossil fuels. In a 2021 report, they cited how the European Union was 90% dependent on imported fossil gas. However, European biomethane production could be able to reach 24% of natural gas consumption in the EU.
Develop circular economies and sustainable agriculture
As biomethane is generated from organic residues, its production relies on turning what is considered as waste into a valuable resource.
Additionally, biomethane gas can also provide the means towards developing a more sustainable agriculture model. As such, it helps managing waste and residues, while also improving soil quality. The result is a healthier ecosystem where carbon sinks are produced and methane emissions from livestock are controlled and minimized
Biomethane market growth
The advantages outlined above provide several reasons why the biomethane market is experiencing continuous growth.
Increased possibilities for the storage and transport of liquid biomethane, as well as growing encouragements from public policies in several territories are also two main reasons for this market’s expansion.
Figures for this growth are provided by several market research and intelligence agencies. For instance, Transparency Market Research quantifies the global biomethane market to grow at a CAGR of 6.9% from 2021 to 2031, meaning the market could expand from US$ 1.9 Bn in 2020 to 4 Bn by 2031.
Today, the main territories pushing for biomethane include the United States, Europe and The People’s Republic of China, accounting for 90% of production around the globe.
UNE-EN 16723-1 regulating the use of biomethane
As the use of biomethane expands across the globe, the need for unified standards emerge. It’s in this context that the standard UNE-EN 16723 (Natural gas and biomethane for use in transport and biomethane for injection in the natural gas network) has been born.
Additionally, the standard is divided in two parts:
- Part 1: UNE-EN 16723-1: Specifications for biomethane for injection in the natural gas network
- Part 2: UNE-EN 16723-2: Automotive fuels specification
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