If the first phase of India’s biofuel journey was defined by ethanol, the next phase will be shaped by a broader set of molecules designed to address more complex segments of the energy economy—particularly diesel.

Unlike petrol, where ethanol has found a natural fit, diesel requires fuels that can integrate seamlessly into existing engines and infrastructure while maintaining fuel characteristics. This has brought renewed focus on advanced alcohols such as bio-isobutanol, which offer a closer alignment with diesel properties.

From a technical standpoint, the case is compelling. Compared to ethanol, bio-isobutanol offers higher energy density, improved miscibility without the need for an external agent, and better compatibility with diesel engines—positioning it as a more viable candidate for large-scale adoption in the diesel pool.

Significance of the effort

India’s progress in this area has moved beyond theoretical exploration. Built on over a decade of sustained research and process refinement, Praj Industries has developed and matured bio-isobutanol technology to a stage where it has been successfully validated for diesel blending applications. Bharat Petroleum Corporation Limited, the Automotive Research Association of India, and leading global engine manufacturers have validated blend stability and performance.

The significance of this effort lies in its end-to-end integration—spanning production technology, fuel blending, engine validation, and regulatory alignment. Such a holistic approach is critical if alternative fuels are to move from pilot projects to commercial deployment.

Equally important is the fit within India’s existing biofuel ecosystem. Bio-isobutanol production can be integrated into current ethanol facilities through modular, bolt-on configurations, enabling producers to switch between products based on market demand. This introduces a new layer of flexibility into the system, while also providing a pathway to absorb India’s ethanol surplus—estimated at nearly 800 crore litres.

Decarbonisation goals

Mr. Sanjay Ganjoo, Director-General of the Indian Federation of Green Energy, believes, “The transition toward advanced biofuels is closely aligned with India’s long-term decarbonisation goals. Achieving energy security in a volatile global environment will require scaling a diversified portfolio of indigenous fuels, particularly those that can displace fossil fuels in high-consumption segments like diesel.”

The policy dimension now becomes critical. India’s ethanol success was underpinned by clear mandates, pricing visibility, and assured offtake. Replicating that model for diesel substitutes will require a similar framework—encompassing blending roadmaps, fuel standards, and incentives for commercial-scale production.

Without such alignment, even the most promising technologies risk remaining at the demonstration stage. The broader shift, as reflected in recent policy discourse, is from managing energy supply to redesigning the energy system itself. In that transition, the expansion of viable fuel pathways will be key. Advanced biofuels represent not just an incremental improvement, but an expansion of the solution space—particularly for segments like diesel, where progress has been limited.

If ethanol establishes the foundation, the next phase will be about building on it—extending decarbonisation across the full spectrum of India’s fuel demand. The opportunity is clear. The question is execution. The geopolitical situation has made it an imperative.

(The author is Managing Director of Samarth SSK Ltd and Co-Chairperson of the Sugar Bioenergy Forum (SBF) under the Indian Federation of Green Energy.)

Published on April 4, 2026