Compressed biogas plants in India: Existing status, technological advances and challenges.

The application of compressed biogas (CBG) in day-to-day livelihood has garnered significant attention in modern day era. It is considered as a potential solution to curb the increasing energy demand and other environmental concerns. The process involves anaerobic digestion (AD) (hydrolysis, acidogenesis, acetogenesis and methanogenesis) of organic substrate under an optimum operating condition (pH, temperature, etc.) via anaerobic microorganisms. This paper aims to describe some major facts about different technological options related to pre-treatment, AD, cleaning and up-gradation system. It also highlights the practical challenges related to high investment cost, inadequate infrastructure, clearance and approval issues, poor feedstock supply chain management etc. in adaption of CBG plants in India. The review examines the significance of both dry and wet continuous digester systems, which includes its advantages and challenges, considering factors, such as feedstock characteristics, process stability, and operational efficiency. It was also found that the type of feedstock and its availability in existing market plays a vital role in smooth functioning of CBG plants. Therefore, the study presents a comprehensive review discussing potential feedstock readily available for CBG plants in Indian market. It was concluded that the usage of agricultural waste (such as Napier grass) has higher CBG potential compared to other feedstock. At the same time, the study presents a broader aspect to policy makers and governing authorities to reframe the existing structure for financial assistantship, regulatory laws, subsidiary schemes etc. for CBG plant owners. It also gives an opportunity to technocrats, industrialist and investors to come-up with an indigenous technology with in-house manufacturing units to promote CBG production in India. [Display omitted] • India has 46 compressed biogas plants with an overall capacity of 272 tonnes/day. • Elaborated the significance of both dry and wet continuous digester systems. • Setting-up a compressed biogas plants requires high investment and operational cost. • Potential market for bio-fuels and bio-fertilizer needs to be explored in India. • Existing financial assistantship and subsidiary schemes need transformation. [ABSTRACT FROM AUTHOR]