Date : 29/11/2023
Relevance: GS Paper 3 - Environment - Renewable Energy and Sustainable development
Keywords: Compressed Biogas (CBG), compressed natural gas (CNG), SATAT Scheme, National Biofuel Policy 2018
- In recent years, India has emerged as a global leader in sugar production, surpassing Brazil and securing a key position in the worldwide sugar economy since the fiscal year 2021-22. Notably, India stands as the second-largest sugar exporter globally.
- The expansion of the ethanol biofuel sector has played a pivotal role in strengthening the sugar industry, contributing to improved financial standing for sugar mills.
Pressmud: A Valuable Feedstock
One significant byproduct in the sugar industry, pressmud, also known as filter cake or press cake, has gained recognition as a valuable resource for green energy production. This residue, a result of sugar processing, can be utilized to generate additional revenue for Indian sugar mills by serving as a feedstock for biogas production through anaerobic digestion, leading to the creation of compressed biogas (CBG). The yield of pressmud typically falls within the range of 3-4 percent weight by weight with the input sugarcane processed in a unit. The use of pressmud as a feedstock for CBG offers several advantages over other feedstocks:
- Simplified Supply Chain: Pressmud eliminates the complexities associated with the feedstock supply chain found in agricultural residue, where biomass harvesting machinery is required for harvesting and aggregation.
- Single or Few Producers: The feedstock is sourced from one or two producers or sugar mills, unlike agricultural residue, which involves multiple producers/farmers within a narrow window of 45 days per year.
- Quality Assurance: Pressmud's quality is not a concern, unlike municipal solid waste, which may contain inorganic material that can damage anaerobic digesters, leading to lower gas output.
- Cost Efficiency: In terms of conversion efficiency, approximately 25 tonnes of pressmud are needed to produce a tonne of CBG, making it more economical than other feedstocks like agricultural residue and cattle dung.
Challenges and Rising Pressmud Prices
- Despite its potential, pressmud comes with specific challenges. Once considered a disposal issue, sugar mill owners have recognized its revenue-generating potential, leading to a substantial increase in pressmud prices over the last two years, rising from Rs 100 per tonne to Rs 500-600 per tonne.
- Pressmud faces competition for use as a fertilizer and in bio-composting, contending with spent wash and being used as fuel in brick kilns. Lack of long-term agreements with sugar mills and the involvement of mediators in procurement further compound the challenges.
- Additionally, storing pressmud proves challenging as it undergoes gradual decomposition, complicating long-term storage and raising production costs.
Regional Production and Sugarcane Cultivation
- Uttar Pradesh and Maharashtra, the primary sugarcane-growing states, contribute to approximately 65 percent of the total sugarcane cultivation area.
- Key sugarcane-producing states include Uttar Pradesh, Maharashtra, Karnataka, Tamil Nadu, and Bihar. Collectively, these states account for around 440 million tonnes out of India's overall sugarcane production, which reached about 495 million tonnes in 2022-23.
- In the fiscal year 2022-23, among the 531 operational sugar mills in India, 330 were privately owned, 190 were cooperative, and 11 were public. India's sugar production for the fiscal year 2022-23 amounted to 32.74 million tonnes, along with approximately 11.4 million tonnes of pressmud.
Potential of CBG from Pressmud
The quantity of pressmud generated has the potential to generate 460,000 tonnes of CBG valued at Rs 2,484 crore. This calculation considers the minimum guaranteed price of Rs 54/kg under the central government’s Sustainable Alternative Towards Affordable Transportation scheme. To fully unlock the potential of pressmud as a resource for the CBG industry, several interventions are necessary:
- State Bioenergy Policies: States with the highest CBG potential from pressmud should implement bioenergy policies that streamline the approval process for projects, providing unified solutions and a variety of incentives, both monetary and non-monetary. Progressive steps taken by states like Uttar Pradesh and Bihar in introducing supportive bioenergy policies for CBG plants serve as exemplary models.
- Control Mechanism for Pressmud Prices: To prevent long-term economic instability in CBG plants resulting from unsustainable feedstock costs, the government should establish a mechanism to control pressmud prices below a specified threshold. Encouraging sugar mills to commit to extended agreements (10-15 years) with CBG plants, featuring an annual rate increase, will ensure economic viability.
- Technological Research for Pressmud Storage: Comprehensive research is essential to developing technologies for pressmud storage that prevent methane emissions into the environment and minimize gas loss from the feedstock. This research should address the challenge of gradual decomposition, complicating long-term storage and raising production costs.
- Training Programs: State renewable energy nodal agencies and biogas development and training centers should conduct periodic training sessions to educate operators on the functioning of CBG plants, handling scientific equipment, and feedstock characterization.
CBG Significance as a fuel
- CBG has calorific value and other properties similar to CNG and hence can be utilized as green renewable automotive fuel.
- Thus, it can replace CNG in automotive, industrial and commercial areas, given the abundance of biomass availability within the country.
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Source- Down To Earth