Integrated biorefineries key to scaling up affordable renewable fuels offtake: Praj

Integrated biorefineries utilizing multiple feedstocks are crucial for optimizing operational costs and mitigating the risks associated with feedstock supply while scaling up the offtake of affordable renewable fuels to achieve net-zero goals, Atul Mulay, president-bioenergy, at biofuels technology company Praj Industries, told Platts, part of S&P Global Commodity Insights, in an interview.

Praj Industries has been a key participant in advancing India's ethanol blending program.

With the growing demand for low-carbon fuels in aviation and road transport, integrated plants are increasingly regarded as future-ready hubs for decarbonization, particularly in sectors that are challenging to decarbonize.

Mulay emphasized that integrated plants have the capability to process a variety of feedstocks, such as sugar molasses and damaged grains for first-generation ethanol, and rice straw for second-generation ethanol, while also utilizing residual biomass for compressed biogas (CBG).

First-generation ethanol is produced from food-based feedstocks such as sugarcane juice, molasses or grains, including corn and rice. It uses conventional fermentation technology and is relatively easy and cost-effective to produce.

Second-generation ethanol is made from non-food biomass such as agricultural residues, including rice straw, wheat straw and bagasse.

The production process for second-generation ethanol is more complex and costly due to the need to break down tough plant materials into fermentable sugars. However, it offers greater sustainability benefits, as it does not compete with food sources and aids in managing agricultural waste.

The integrated bioenergy complexes, along with additional bio-based products such as compressed biogas, biobitumen, distillers' dried grains with solubles (DDGS), and distillers' corn oil, among others, are anticipated to play a crucial role in enhancing the cost-competitiveness and sustainability of India's biofuel sector.

"The advantage lies in what we call a co-located or integrated plant," Mulay said. "When you combine an ethanol plant with CBG, it enables the use of waste from ethanol production to generate CBG, which has a lower price and carbon intensity than fossil-based CNG. This makes CBG an attractive option and this synergy leads to better economics and operational efficiency."

India's National Bioenergy Programme and the GOBARdhan scheme support integrated bioenergy solutions by offering financial and regulatory incentives for the production of CBG and biomanure.

"Integration allows us to optimize costs and de-risk feedstock supply," Mulay said. "Additionally, with the ability to produce co-products such as DDGS, distillers corn oil, compressed biogas, and biobitumen, these plants improve overall project viability."

Co-product valorization

Integrated biorefineries rely on co-product valorization as a key strategy to boost affordability by creating additional revenue streams, Mulay said.

For example, grain-based ethanol plants can produce distillers corn oil and DDGS, whereas CBG plants yield organic fertilizers such as liquid and solid fermented organic manure.

In second-generation ethanol facilities, lignin, a byproduct, can be converted into biobitumen, a sustainable alternative to fossil-based bitumen for road construction.

"This not only provides an additional revenue stream but also contributes to import substitution and carbon footprint reduction," said Mulay.

In December 2024, Minister for Road Transport and Highways Nitin Gadkari inaugurated India's first biobitumen-based 1 km national highway stretch on the Nagpur-Mansar bypass on NH 44. The lignin-based biobitumen was developed by Praj in collaboration with CSIR-Central Road Research Institute.

In 2022, Praj laid a trial stretch of biobitumen road in Halol, Gujarat, which proved durable after 2.5 years and three monsoons.

SAF and biohydrogen focus

Praj is also exploring the commercialization of SAF, aiming to support the aviation sector in achieving its decarbonization goals.

In May 2023, Praj partnered with Indian Oil Corp. to supply an indigenous SAF blend for India's first commercial flight AirAsia I5-767 from Pune to Delhi.

The company also perceives strong potential in biohydrogen, sourced from organic waste and agricultural residues, as a cleaner and more energy-efficient alternative to electrolytic hydrogen.

Requiring only 10 kW/kg of hydrogen compared with 60 kW for electrolysis, biohydrogen utilizes organic waste and biomass and is cost-effective.