Benefits of Biogas

• 26 Oct 2022

For Prelims: Biogas, Sustainable Development Goals, compressed biogas (CBG), liquefied biogas (LBG), hydrogen and methanol, Sustainable Alternative Towards Affordable Transportation (SATAT).

For Mains: Significance of Biogas.

Why in News?

Countries around the world are turning to biogas and biomethane to enhance their energy security.

What is Biogas?

• About:
  • Biogas, a renewable fuel produced using the anaerobic digestion process from organic feedstock, is primarily composed of methane (50-65%), carbon dioxide (30-40%), hydrogen sulfide (1-2.5%) and a tiny fraction of moisture.
  • It contributes to all 17 of the United Nation’s Sustainable Development Goals and can also be converted to produce numerous sustainable transportation fuels.
• Variants:
  • Compressed Bio Gas (CBG): The upgraded or high-purity biogas (after removal of unwanted components like carbon dioxide, hydrogen sulphide and moisture) compressed at 250 bar pressure results in a fuel called compressed biogas (CBG). This has properties similar to compressed natural gas (CNG) and could be directly used to power CNG engines.
    • Drawback: Its existence in the gaseous form, which demands bigger volumes for transportation. Therefore, it is considered more suitable to power small-sized vehicles, though heavy engines have been used for short-distance driving.
  • Liquified Bio Gas (LBG): If the biogas-derived methane is liquefied by cooling it at -162 degrees Celsius, the fuel thus obtained is liquefied biogas (LBG). It has a higher energy density that lowers storage space requirements.
    • At atmospheric pressure, the energy density of liquid methane is roughly 600 times more than that of gaseous methane and 2.5 times greater than that of methane at 250 bar.
    • Advantages: It can become a viable alternative fuel for heavy-duty road transportation since it has a comparatively high energy density.
      • It is becoming attractive to the shipping industry in addition to being utilised in heavy-duty vehicles.
• Applications:
  • Biogas can be converted to produce numerous sustainable transportation fuels.
  • In addition to being used directly as fuel, biomethane can also be transformed into other fuels such as hydrogen and methanol. The primary method for producing hydrogen encourages the reforming of light hydrocarbons, particularly methane, which makes up a significant portion of biogas.
  • Gasification is performed by limiting the amount of oxygen and steam present in the reaction and heating the bio-methane to high temperatures (usually over 600°C).
    • Syngas, a mixture of hydrogen and carbon monoxide, is created as a result of this process. The hydrogen produced after the removal of carbon monoxide could be used in fuel cells to generate power.
    • Methanol can also be generated from syngas. Methanol is an effective fuel; it emits less particulate matter and nitrogen oxide (NOx) than gasoline. It can be used also as a transportation fuel by blending or entirely replacing gasoline. It’s more affordable than LNG.

What is the Indian Scenario regarding Biogas and Methanol?

• CBG is the only transportation fuel from biogas for which commercialisation efforts have been made.
• Currently, LBG, hydrogen and methanol are not produced from biogas in India. The main reasons are:
  • Unavailability of biogas in bulk for such derivatives,
  • Absence of infrastructure to generate and market these fuels,
  • Deficiency of modified automobile engines as well as the lack of effective. Research and development push to improve process economics.
• Government Initiatives: The Indian government has been encouraging private businesses to set up CBG plants and provide CBG to oil marketing companies for sale as automotive and industrial fuels under the Sustainable Alternative Towards Affordable Transportation (SATAT) scheme launched in 2018.
  • Further, the Indian government and Niti Aayog have outlined roadmaps to hasten our transition towards green fuels and promote LNG, hydrogen and methanol.

Source: DTE