Transforming Sugarcane Residues into 2G Ethanol and SAF with Zero Emissions

By – Dilip Patil,

(Co-Chairman, IFGE’s Sugar Bioenergy Forum and Council Member DSTA)

At the Deccan Sugar Technologist Association’s (DSTA) annual conference yesterday, Shri Vivek Verma, Managing Director at Spray Engineering Devices Limited (SEDL), delivered a compelling presentation on a cutting-edge research paper co-authored with Vimarsh Verma. Titled “Next-Generation Biomass Refining for Second-Generation Ethanol and Sustainable Aviation Fuel: A Scalable Pathway for India’s Bioeconomy,” the work introduces an innovative, electrolyzer-integrated platform designed to convert sugarcane bagasse and other non-food biomass into second-generation (2G) ethanol and sustainable aviation fuel (SAF). This breakthrough promises to propel India toward energy independence and a robust circular bioeconomy.

The conference, a hub for sugar industry innovators, technologists, and policymakers, featured discussions on sustainable advancements in sugar and related sectors. Verma’s paper emphasizes SEDL’s low-carbon technology, incorporating mechanical vapor recompression (MVR), steam-free pyrolysis, and electrically heated gasification to achieve exceptional efficiency and near-total carbon utilization. It taps into India’s biomass abundance—around 990 million metric tons (MMT) generated yearly from agricultural, forestry, and municipal waste, with sugarcane residues like bagasse being a prime resource.

As a leading emerging economy with over 1.407 billion people and more than 3,000 hours of annual solar irradiation, India produces over 430 MMT of sugarcane annually, per MNRE reports (2022-23). This crop drives multiple value chains, from sugar and jaggery to molasses and press mud, but bagasse—the lignocellulosic residue after juice extraction—has historically been underutilized, often burned inefficiently or wasted. SEDL’s approach reimagines this as a renewable powerhouse, focusing on non-food biomass to preserve food security.

Indian biomass is categorized into food-based (e.g., cereals, fruits) and non-food-based (e.g., stalks, husks, bagasse, MSW). Bagasse, comprising 40-45% cellulose, 25-35% hemicellulose, and 20-25% lignin, offers high biofuel potential, with dry bagasse yielding 4,800-5,000 kWh/ton and a calorific value of 17-19 MJ/kg—superior to MSW (8-10 MJ/kg) or cow dung (9-10 MJ/kg).

SEDL’s multi-pathway system aligns with circular principles, maximizing carbon atoms. For 2G ethanol, it involves MVR drying, pyrolysis for biochar and volatiles, electrical gasification to syngas (CO + H₂), microbial fermentation, and distillation. Efficiency data shows H₂:CO ratios impacting yields:

· 0:1: 33.3% carbon, 72.4% energy efficiency.
· 1:1: 66.7% carbon, 78% energy.
· 2:1: 100% carbon, 80% energy.
· Up to 6:0 (CO₂ hydrogenation): 100% carbon, 84% energy.
For SAF, the process includes low-energy drying, gasification, Fischer-Tropsch synthesis, hydrocracking, and upgrading for clean jet fuel.

This shifts from direct combustion (~2.34 barrels of crude oil equivalent per ton) to advanced valorization, boosting economics and cutting emissions. With agriculture at 16% of GDP and 60% workforce (MNRE 2022-23), it supports rural growth, green hydrogen, and decentralized bio-refineries producing bioplastics, biofertilizers, and chemicals.

The paper aligns with policies like MNRE’s Biomass Power & Cogeneration Programme (2023) and India’s 5% GDP growth trajectory (FY 2017-2023, RBI 2023). Attendees commended its scalability and MVR-Lite integration—a compact, automated evaporation system eliminating boilers and towers.

In my view, this SEDL technology stands out as a transformative boon for the sugar industry, which frequently contends with fluctuating sugar prices, seasonal operations, and stringent environmental regulations. By fully valorizing bagasse—saving 100% for high-value 2G ethanol and SAF—sugar mills can diversify revenue streams beyond traditional sugar, tapping into biofuels that avoid food competition. This could dramatically enhance profitability, with advanced conversions achieving up to 100% carbon efficiency.

Operationally, the MVR-Lite and electrolysis-integrated processes could slash energy costs by 70-80% via closed-loop, zero-fossil-fuel designs, enabling emission-free operations. This directly supports compliance with India’s goal of achieving a 20% ethanol blending (E20) target by 2025-26, providing a crucial pathway to meet and sustain this ambitious goal using non-food feedstocks. It also positions mills to secure subsidies under MNRE initiatives.

In rural areas, where sugar mills are economic anchors, this fosters employment in bio-refining while advancing agricultural sustainability through 100% drip irrigation, press mud nutrient recycling, and green solar synergies. Ultimately, it redefines sugar mills as versatile bioeconomic hubs, building resilience against market swings and elevating Indian producers to global leaders in circular manufacturing.