Biogas, a renewable fuel source, is growing in prominence around the world as countries look to enhance their energy security. Produced via anaerobic digestion of organic feedstock, biogas primarily consists of methane, carbon dioxide, and hydrogen sulfide. It contributes to all 17 of the United Nations Sustainable Development Goals and can be converted into various sustainable fuels. This article will discuss the characteristics of biogas, its variants, applications, several government initiatives, and the Indian scenario regarding the use of this versatile power source.
Understanding Biogas
Biogas, an eco-friendly fuel, is produced through the anaerobic digestion process from organic feedstock. Its primary components are methane (50-65%), carbon dioxide (30-40%), and hydrogen sulfide (1-2.5%), with a minute fraction of moisture. This renewable fuel contributes to all 17 of the United Nation’s Sustainable Development Goals and can also be converted to produce numerous sustainable transportation fuels.
Variants of Biogas: Compressed BioGas (CBG) and Liquified BioGas (LBG)
Upgraded or high-purity Biogas results in a fuel called compressed biogas (CBG), which occurs after unwanted components like carbon dioxide, hydrogen sulfide, and moisture are removed. CBG has properties similar to compressed natural gas (CNG) and could be directly used to power CNG engines. However, as it exists in gaseous form, it requires larger volumes for transportation which makes it more suitable for powering small-sized vehicles.
Another type of biogas, Liquefied BioGas (LBG), is derived when the biogas-generated methane is liquefied by cooling it to -162 degrees Celsius. LBG has a higher energy density lowering the storage space required. It is becoming increasingly attractive to the shipping industry and heavy-duty vehicles because of its high energy density.
Applications of Biogas: Hydrogen and Methanol
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 includes the reforming of light hydrocarbons, notably methane, a significant constituent of biogas. Gasification is achieved by limiting the oxygen and steam present and heating the bio-methane to high temperatures. This process produces Syngas, a mixture of hydrogen and carbon monoxide. Methanol, an efficient fuel that emits less particulate matter and nitrogen oxide than gasoline, can also be generated from syngas.
Indian Scenario regarding Biogas and Methanol
In India, CBG is the only transportation fuel from biogas that has seen commercialisation efforts. However, there are no current productions of LBG, hydrogen, and methanol from biogas due to constraints such as the unavailability of biogas in bulk for such derivatives, lack of infrastructure, deficiency of modified automobile engines, and inadequate research and development push to improve process economics.
Government Initiatives: SATAT Scheme and Green Fuel Roadmaps
The Indian government has been encouraging private businesses to establish CBG plants and supply oil marketing companies with CBG as automotive and industrial fuels under the Sustainable Alternative Towards Affordable Transportation (SATAT) scheme launched in 2018. Furthermore, the Indian government, together with Niti Aayog, have drafted roadmaps to speed up our transition towards green fuels and endorse LNG, hydrogen and methanol.
