This post is a part of BioBiz’s Bio-CNG Perspectives.
BioBiz, a division of EAI, is a leading market intelligence & strategic consulting firm for the Indian bio-based sectors.
This blog post uses the terms bio-CNG and renewable natural gas (RNG) interchangeably.
Bio-CNG or bio-compressed natural gas, also known as sustainable natural gas or biomethane, is a biogas which has been upgraded to a quality similar to fossil natural gas and having a methane concentration of 90% or greater. As the gas is derived from natural and renewable sources, it is also termed renewable natural gas (RNG).
Bio-CNG is an emerging segment in India. With the energy industry moving towards sustainability in the wake of climate change, many entrepreneurs are exploring waste to energy as an avenue for production of sustainable fuels. Anaerobic digestion is one such avenue for conversion of wet wastes to gaseous fuel (biogas). However, biogas cannot be used in its raw form as a fuel at commercial scales owing to its poor quality such as lower calorific value. Hence, there is a need for an additional technology to convert biogas into a product which has characteristics similar to other conventional fossil fuels like LPG, natural gas, diesel, etc. This product is called bio-CNG that has gained attention in recent times as a potential commercially usable form of fuel.
However, before venturing into the segment, it is essential for project developers to understand the potential benefits of RNG and its production potential in India. This blog post provides an overview of renewable natural gas, its characteristics, and its production potential in India.
What is biogas?
Biogas is a combustible mixture of gases. It consists mainly of methane (CH4) and carbon dioxide (CO2) and is generated by the bacterial decomposition of organic wastes in the absence of oxygen (anaerobic digestion). Biogas is produced either
- Naturally, as landfill gas (LFG), which is produced by the breakdown of biodegradable waste inside a landfill due to chemical reactions and microbes, or
- As digested gas, produced inside an anaerobic digester
While the former method, if the gas is not captured, results in an increase in GHG emissions due to the generation of methane, the latter method generates biogas within the equipment that can be used as a cooking fuel.
Anaerobic digestion has been in use since long; however, its commercial potential has only been recently explored with technology advancements. These advancements enable the businesses to produce a high-value, commercial product called bio-compressed natural gas (bio-CNG) or renewable natural gas (RNG) that can find applications in various sectors as a fuel.
What is renewable natural gas (RNG)?
RNG is the upgraded, compressed, commercially usable form of biogas that can be produced by anaerobic digestion of biodegradable wastes such as agro-wastes, industrial wastes and commercial wastes. RNG contains about 92-98% of methane and only 2-8% of carbon dioxide. The calorific value of RNG is about 52,000 kilojoules (kJ) per kg, which is 167% higher than that of biogas. The high methane content and calorific value, combined with the low quantity of moisture, hydrogen sulphide and impurities, makes RNG an ideal fuel for automobiles, industries and commercial sectors. The low emission levels of RNG also make it a more environment-friendly fuel than biogas.
Potential of RNG as a fuel in India
RNG is exactly similar to the commercially available compressed natural gas in its composition and energy potential. Given the abundance of biomass in the country, RNG has the potential to replace natural gas in automotive, industrial and commercial uses in the coming years. It is also estimated to have the potential to replace two-thirds of India’s natural gas imports, which was estimated to be about 22 million tons in 2018-19.
The potential for RNG production from various sources in India is estimated at about 62 million tons per annum, which in turn helps bring down dependency on crude oil imports. RNG also holds great promise for efficient waste management and in tackling the problem of urban air pollution due to farm stubble-burning and carbon emissions. The process of anaerobic digestion also produces enriched organic manure which can be used as fertiliser.
Subsidies for RNG projects
In July 2016, the Waste to Energy Division of MNRE launched a programme on energy from urban, industrial and agricultural wastes/residues which aims to promote setting up of projects for recovery of energy in the form of biogas/RNG/enriched biogas from the above mentioned waste sources. Central Financial Assistance (CFA) of INR 4 crore per 4800 kg of RNG/day generated from 12,000 cubic metre Biogas /day has been announced in 2016, with a limitation of maximum CFA as INR 10 crore/project.
In Oct 2018, Government of India launched the SATAT initiative for setting up 5000 RNG plants across India by 2025.
Current status of RNG in India
As of 2019, there are 17 RNG plants operational in India, with a combined capacity of 50,428 kg per day. These plants are spread over nine states of which, Maharashtra leads in terms of the largest capacity as well as the highest number of plants.
With the above trends, RNG market in India is expected to have a steady growth in the near future and business opportunities exist for entrepreneurs who are exploring to venture into this emerging sector.
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