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Saturday, August 29, 2026

Chonnam National University researchers investigate how biodiesel feedstocks and production pathways affect their life cycle sustainability

Study provides biofuel producers with a practical, multi-dimensional framework for choosing feedstocks by weighing both climate impact and air pollution together

Chonnam National University, The Research Information Management Team, Office of Research Promotion

Impact of feedstock choice in biodiesel sustainability — image:
Researchers reveal that waste-derived pathways exhibit the lowest greenhouse gas emissions while plant-based pathways dominate by Scope 3 contributions from farming and indirect land-use change.
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Credit: Professor Boreum Lee from Chonnam National University, Republic of Korea

For mitigating climate change and limiting global warming to within 1.5 °C, scaling up global renewable energy capacity is an important goal. However, this effort towards transition to clean energy faces significant resource constraints. To address this challenge, diverse approaches are required like biodiesel, which can serve as a crucial bridge technology for decarbonization of the transportation sector while renewable energy is scaled up.

Biodiesel is compatible with already existing diesel infrastructure and can be deployed quickly without extensive modifications, making it a particularly promising solution. However, not all biodiesel is equally sustainable. Its environmental impact depends strongly on the feedstock used and the way it is produced. This creates a complex decision-making landscape for policymakers and stakeholders, necessitating comprehensive life-cycle assessments (LCAs) of different biodiesel pathways. Although previous LCAs have compared biodiesel pathways, most have focused primarily on total greenhouse gas (GHG) emissions and a limited range of feedstocks. They have also rarely examined feedstock-specific mitigation strategies or air-pollution impacts.

To address this gap, a research team led by Professor Boreum Lee along with Mr. Sanghyuk Koh, both from the Department of Environment and Energy Engineering, Chonnam National University, Republic of Korea, presents a comprehensive Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET)-based framework for LCA across five different biodiesel feedstocks. Their study was made available online on July 01, 2026 and was published in Volume 422 of Applied Energy on November 01, 2026.

The study considered three plant-based feedstocks, namely soy oil, carinata oil, and palm oil, representing diverse agricultural systems, and two waste-derived feedstocks, namely used cooking oil (UCO) and beef tallow. A Well-to-Tank approach, based on the GREET model, was adopted aiming to capture emissions across the full life cycle. The full life cycle was divided into three categories: Scope 1 that covers direct emissions during biodiesel production, Scope 2 that encompasses indirect emissions from energy use, and Scope 3, which integrates emissions from major upstream and downstream processes.

For plant-based feedstocks, the upstream processes included farming, oil extraction, refining, transportation, and emissions from indirect land use change (ILUC). In contrast, waste-derived feedstocks included rendering, oil extraction, and refining as upstream processes, while overseas import and long-distance international transport were excluded.

Emissions analysis showed that waste-derived feedstocks consistently demonstrated lower GHG emissions than plant-based oils. This is mainly due to the absence of emissions from upstream agriculture and land use. Among plant-based options, carinata oil showed the lowest emissions as it avoids ILUC emissions. For plant-based feedstocks, Scope 3 farming processes had the greatest contribution to GHG emissions, while for waste-derived feedstocks Scope 1 and the Scope 3 refining stage were dominant.

“Waste-derived pathways, when paired with renewable energy inputs in processing, can achieve net-negative emissions, meaning they could actually remove more carbon from the atmosphere than they emit with a reduction of up to 346–352% relative to their own baseline (conventional-input) production,” says Prof. Lee.

Interestingly, air-pollution analysis showed that low GHG intensity did not necessarily mean uniformly low pollution. For example, carinata oil, despite its lowest plant-based GHG emissions, had the highest volatile organic compound (VOC) and carbon monoxide (CO) levels across all pathways. These findings highlight the importance of considering air-pollution impacts alongside GHG emissions when evaluating biodiesel sustainability.

Furthermore, Monte Carlo simulation-based uncertainty analysis, aimed at capturing the effect of data variability, showed wider emission ranges for plant-based pathways, compared to much narrower distributions for waste-derived feedstocks.

Importantly, best-case GHG mitigation scenarios revealed emission reduction potentials ranging from 66% to 352%. Waste-derived feedstocks offered the greatest mitigation potential, achieving net-negative GHG emissions through the use of renewable energy in rendering and refining processes.

“Our findings argue against one-size-fits-all biofuel mandates: regions with strong waste-collection infrastructure should prioritize used-oil-based biodiesel, while agricultural regions may benefit more from dedicated energy crops. In the near future, this feedstock-specific, region-aware analysis approach will help policymakers design smarter policies and foster the broader biofuel industry, including aviation and marine fuels, paving the way towards a more sustainable future,” concludes Prof. Lee.

***

Reference

Title of original paper: Decarbonizing biodiesel supply chains: a GREET-based life cycle assessment with Scope 1–3 emissions and best-case mitigation

Journal: Applied Energy

DOI: https://doi.org/10.1016/j.apenergy.2026.128326

About the institute
Chonnam National University (CNU), established in 1952, is one of South Korea's leading national universities located in Gwangju. Building on its founding commitment to cultivating leaders of integrity and professional excellence, CNU contributes to national development and global progress through the pursuit of knowledge, ethical responsibility, and inclusive excellence. Guided by the core motto “Truth, Creativity, and Service,” the university advances research, education, and public engagement that strengthen resilient societies, foster sustainable development, and promote the well-being of future generations. As a trusted partner in the global community, CNU remains dedicated to addressing complex challenges in an increasingly interconnected world.

Website: https://global.jnu.ac.kr/jnumain_en.aspx

About Professor Boreum Lee
Dr. Boreum Lee is a Professor at the Department of Environment and Energy Engineering, Chonnam National University, Republic of Korea. His research focuses on the design and evaluation of carbon-neutral process systems, including hydrogen production, CO₂ capture, utilization and storage, ammonia synthesis and cracking, Power-to-X technologies, and water treatment. By integrating Aspen Plus process simulation with techno-economic and environmental assessments, he works to develop and optimize sustainable energy and chemical processes.

Website: https://boreumlee.com/

About Mr. Sanghyuk Koh
Mr. Sanghyuk Koh is a master’s candidate at the Department of Environment and Energy Engineering, Chonnam National University, Republic of Korea. His research focuses on the life cycle assessment and techno-economic analysis of biodiesel supply chains and green hydrogen production to evaluate their environmental and economic sustainability.

Journal

Applied Energy

DOI

10.1016/j.apenergy.2026.128326

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Decarbonizing biodiesel supply chains: a GREET-based life cycle assessment with Scope 1–3 emissions and best-case mitigation

Article Publication Date

1-Nov-2026

Friday, August 28, 2026

E20 Petrol: Balancing Energy Security – Analysis

Image: Grok

August 28, 2026
By Patial RC

Key Takeaways:

India’s E20 ethanol-blend push is credited with cutting oil-import exposure, saving foreign exchange, and opening markets for sugarcane, maize, and surplus grain—but the author says net benefits are assumed more than measured.

Hidden costs include ethanol’s lower energy content (fewer km per litre at similar pump prices), uneven gains for small farmers versus mills, food-versus-fuel risk, and water use in stressed regions.

The piece urges a published cost-benefit ledger, residue-based second-generation feedstocks, clearer consumer choice for older vehicles, and an independent review before raising blends further. Farmers, Consumers and Sustainability

India’s transition towards ethanol-blended petrol represents one of the country’s most significant energy-policy initiatives of the past decade. The move towards E20—petrol containing up to 20 per cent ethanol—has been driven by several legitimate national objectives: reducing dependence on imported crude oil, conserving foreign exchange, improving energy security, creating additional markets for agricultural produce and reducing emissions.

Measured against these objectives, the programme has achieved considerable scale and speed. India imports a substantial proportion of its crude-oil requirements, leaving the economy exposed to international prices, exchange-rate movements and geopolitical disruptions. Replacing a portion of imported petroleum with domestically produced ethanol therefore provides a degree of insulation from global oil-market volatility.

The strategic value of that insulation became particularly apparent during periods of international uncertainty. When crude prices rise sharply because of geopolitical tensions or disruption to supply routes, a portion of India’s transport-fuel requirement is effectively sourced domestically rather than being entirely exposed to international crude prices and the dollar. In that sense, ethanol blending can be viewed not merely as an environmental programme but also as a form of energy-security insurance.

The important question is not whether E20 has benefits—it clearly does—but whether those benefits and costs are being measured comprehensively and distributed fairly among farmers, consumers, oil companies, distilleries and the wider economy.
The Economic Case for Ethanol

The economic rationale for ethanol blending is straightforward. Every litre of ethanol used in petrol represents a corresponding reduction in the quantity of petroleum that has to be imported, subject to the actual energy content of the respective fuels.

The programme has also created a large and predictable market for agricultural feedstocks, including sugarcane, maize and certain surplus or damaged grains. This can provide additional revenue streams for sugar mills, distilleries and agricultural producers, while encouraging investment in processing capacity and rural infrastructure.

There are environmental benefits as well. Ethanol is a renewable fuel and, depending on the feedstock, cultivation practices, processing technology and transport involved, blending can reduce the lifecycle carbon intensity of petrol.

These are important gains. India’s energy transition cannot be assessed solely from the perspective of the price paid at a petrol pump. Foreign-exchange savings, energy security, rural employment, industrial investment and emissions reduction also have economic value.

At the same time, the net benefit needs to be measured rather than assumed.
The Cost of the Energy Transition

One of the less discussed characteristics of ethanol is its lower energy content compared with petrol. Ethanol contains substantially less energy per litre, which means that a vehicle may require more blended fuel to travel the same distance.

The government’s own assessments acknowledge some loss in fuel economy, while earlier projections by NITI Aayog indicated that the impact could be more significant for vehicles designed for lower ethanol blends. This creates an important consumer question.

If E20 is sold at essentially the same pump price as conventional petrol, but provides fewer kilometres per litre, the motorist’s effective cost per kilometre can rise even if the price per litre does not. That does not necessarily make E20 an uneconomic policy. If the additional cost to the consumer is outweighed by foreign-exchange savings, energy-security benefits and environmental gains, the programme can still produce a positive national return.But that calculation should be transparent.

A useful next step would therefore be publication of a comprehensive cost-and-benefit assessment of E20, including the cost of ethanol, petrol displaced, transportation and blending, taxation, vehicle efficiency effects and the value of reduced petroleum imports. Such transparency would make the debate considerably more constructive.
Who Ultimately Benefits?

The programme is also frequently presented as an opportunity for farmers. The creation of a large domestic ethanol market can certainly benefit agricultural producers, but the distribution of those benefits deserves closer examination.

Payments made by oil marketing companies to distilleries and sugar mills do not automatically translate into equivalent increases in farm incomes. The extent to which the additional value reaches the farmer depends on procurement arrangements, feedstock prices, market conditions, processing margins and the bargaining position of individual producers.

Large farmers and organised agricultural producers may be better positioned to benefit from assured demand than small and marginal cultivators, who often have limited marketable surpluses.

This is particularly relevant in the case of maize. If government policy encourages greater maize production for ethanol while market prices remain below the declared minimum support price, questions naturally arise about how much of the value generated by the ethanol market is actually reaching cultivators.

These questions need not imply that the ethanol programme has failed. Rather, they point to the need for better measurement of the programme’s farm-level outcomes.

The ultimate test of the agricultural component should therefore be simple: has the additional demand for ethanol translated into a sustained improvement in farm incomes?
Food Versus Fuel

Another issue requiring careful consideration is the increasing use of food-related feedstocks for ethanol.

Maize, sugarcane and rice have legitimate competing uses in India’s food and agricultural economy. In normal years, there may be sufficient supplies to accommodate both food and fuel requirements. However, droughts, crop failures, international disruptions or sudden changes in domestic demand can alter that balance quickly.

The use of surplus, damaged or otherwise unsuitable grain for fuel can be economically sensible because it creates value from material that may not otherwise enter the food chain.

The situation becomes more complicated when cultivable resources are deliberately redirected towards fuel production at the expense of food, feed or other essential uses.

This is not an argument against ethanol. It is an argument for maintaining flexibility in feedstock policy and ensuring that energy security does not unintentionally create a food-security challenge.
The Water Question

Water may ultimately prove to be one of the most important sustainability questions surrounding ethanol.

The environmental footprint of ethanol varies substantially according to the feedstock. Sugarcane is water-intensive, while grain-based ethanol also carries the water requirements associated with cultivation.

Therefore, the environmental benefit of replacing imported petrol cannot be assessed as stand alone. The entire lifecycle—from cultivation and irrigation to processing, transportation and blending—needs to be considered. This becomes particularly important in regions already experiencing groundwater stress.

A sensible long-term strategy would encourage feedstocks and technologies that impose lower pressure on scarce water resources. Agricultural residues, crop waste and other non-food biomass could play a progressively greater role through second-generation biofuel technologies. Such diversification would also reduce the potential conflict between food and fuel.

The Consumer Perspective

The motorist is another important stakeholder in the transition.Consumers are being encouraged to move towards cleaner and more efficient forms of mobility while simultaneously facing higher fuel prices, changing vehicle regulations and the costs associated with newer technologies.

Petrol vehicles remain an important part of India’s transport system. If higher ethanol blends result in even modest reductions in fuel economy, the impact will be felt most directly by high-mileage users, particularly two-wheeler owners and households for whom fuel expenditure represents a significant share of monthly income.

Vehicle compatibility is another consideration. Newer vehicles are increasingly designed and calibrated for higher ethanol blends, but India’s vehicle fleet is large and diverse, with millions of older vehicles still on the road. The objective should therefore be to ensure that the transition is technologically sound as well as environmentally desirable.

One possible transitional approach is to retain consumer choice through the availability of ethanol-free petrol where technically and economically feasible, particularly for older vehicles, while the newer fleet progressively moves towards higher blends.

Capacity, Investment and the Next Phase

The rapid expansion of ethanol production has also resulted in substantial investment in distilleries and associated infrastructure. This investment is positive in principle. However, installed capacity must ultimately correspond with sustainable demand. Excess capacity can create pressure for higher blending mandates, additional feedstocks or new markets simply to maintain utilisation.

That is why the move from E20 towards still higher blending levels should be guided by evidence rather than by capacity considerations alone. Before moving further, India would benefit from an independent assessment of the E20 experience—covering energy security, foreign-exchange savings, carbon emissions, agricultural incomes, food availability, water consumption, consumer costs, vehicle performance and the financial health of the ethanol industry.

A More Balanced Way Forward

The case for E20 need not be framed as a choice between supporting ethanol and opposing it.A more constructive approach would recognise that ethanol can be an important component of India’s energy strategy while also acknowledging that every energy policy produces winners, costs and trade-offs.Five areas deserve particular attention:

First, greater transparency. A clear per-litre cost and benefit structure for E20 would allow consumers and policymakers to understand what they are paying for and where the economic value is being created.

Second, better measurement of farmer benefits. The programme should be assessed not simply by the value of ethanol purchased from distilleries, but by its measurable impact on farm incomes, particularly for small and marginal cultivators.

Third, feedstock diversification. Greater emphasis should gradually be placed on agricultural residues, waste biomass and other non-food feedstocks, reducing pressure on food supplies and water resources.

Fourth, consumer protection. The impact of ethanol blending on fuel economy, vehicle compatibility and cost per kilometre should be transparently communicated. Where necessary, appropriate transitional mechanisms could be considered for older vehicles and vulnerable consumers.

Fifth, independent periodic review. The E20 programme should be evaluated on a full lifecycle basis before the country moves towards substantially higher blending levels. The objective should not simply be to maximise the percentage of ethanol in petrol, but to maximise the net national benefit.

Conclusion

India’s ethanol programme deserves recognition for its ambition and for the strategic benefits it can provide. Reducing dependence on imported crude, strengthening domestic energy security, creating agricultural markets and encouraging investment in rural industry are all legitimate national objectives.At the same time, the success of E20 should not be judged solely by the achievement of a blending target.

The more important questions are whether the foreign-exchange savings justify the overall economic cost, whether farmers receive a fair share of the value created, whether food and water security are adequately protected, and whether motorists receive an equitable outcome from the transition.

The debate, therefore, should not be ethanol versus petrol, nor should it become a contest between government policy and its critics. The real objective is to ensure that India’s ethanol strategy remains economically viable, environmentally sustainable, farmer-oriented and fair to consumers.

E20 can be an important force multiplier for India’s energy security. But its long-term credibility will depend on transparency, independent assessment and the willingness to adjust the policy wherever evidence shows that the costs are falling disproportionately on farmers, consumers or natural resources. A successful energy policy must ultimately balance all these interests.

Note: Broad issues discussed in the article need to be specifically be considered by non-oil producing nations with agriculture surplus.

About Patial RC
Patial RC is a retired Infantry officer of the Indian Army and possesses unique experience of serving in active CI Ops across the country and in Sri Lanka. Patial RC is a regular writer on military and travel matters in military professional journals. The veteran is a keen mountaineer and a trekker.
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Thursday, August 27, 2026