What makes a sustainable fuel truly sustainable?

By Morgan Rote, Associate Vice President, U.S. Fuels and Transportation, EDF

Rising demand for alternative fuels brings critical questions: Which fuels? And how clean are they, really?

The answers: It depends. And right now, we have an incredible opportunity to bring stakeholders together around sound science, innovative policies and best practices to get the sustainable fuels ecosystem right as it develops.

Energy security meets climate reality

The strategic appeal of a diverse clean fuel mix is obvious. Countries that secure a portfolio of domestically produced hydrogen, e-fuels, sustainable biofuels and other low-emissions fuels can reduce reliance on unstable fossil import markets while growing their economies.

They can protect themselves from geopolitical shocks, stabilize industrial inputs and foster robust export industries — all while advancing a clean energy transition.

Alternative fuels could help clean up the so-called hard-to-abate sectors, i.e. industries that require a lot of energy to reach very high temperatures or to move heavy loads. Heavy trucking, shipping, aviation, steel, cement and chemicals are together responsible for roughly one-third of global carbon emissions, and as long as those sectors remain reliant on fossil fuels, global decarbonization efforts will fall short.

But ambition should not come at the expense of environmental integrity.

A peer-reviewed perspective article from our own EDF scientists, published in the journal Environmental Science & Technology, makes it clear: sustainability is not an inherent property of any molecule — it is a feature of a fuel’s full value chain. 

How a fuel is made, managed and used all determine whether that fuel is genuinely sustainable, or no better (or even worse) than fossil fuels.

The most successful strategies will build in environmental integrity from the start, to maximize all potential benefits.

Beyond labels: Why the details matter

Calling something a sustainable fuel based on its potential does not guarantee sustainability. Because the term encompasses dozens of fuel types and feedstocks, and a wide variety of production pathways and value chains, the environmental and social outcomes can vary drastically.

A few high-stakes examples:

• Biofuels derived from crops grown on recently converted forest land could emit more carbon dioxide than the fossil fuels they displace — not to mention negative impacts on biodiversity, water and local communities.
   
• Hydrogen produced from natural gas without high carbon capture rates and permanent storage, or with high upstream methane leakage, might offer little or no climate benefit, and could lock in new fossil infrastructure for decades.
   
• E-fuels or bio-derived fuels made with fossil-intensive electricity or inefficient processes might carry hidden carbon and air-quality burdens.

Put simply: Fuels that are irresponsibly sourced or poorly regulated risk locking in climate, environmental and social harms right when the world can least afford them. That’s why fuel diversification must come with not only big aspirations, but high standards grounded in science. This is not only smart — it’s doable.

What policy and practice need to look like

What’s needed now is to channel momentum (and finance) into pathways that deliver real climate, environmental and societal value. For policymakers, the steps should be clear:

• Prioritize electrification (with electricity made from new renewable energy sources) wherever feasible as the most efficient use of energy; use alternative fuels where no better options exist, maximizing positive impacts.
   
• Encourage investment, incentives and technological innovation in truly low-impact fuel pathways.
   
• Require transparent accounting of lifecycle emissions and societal and environmental impacts for every fuel pathway — from feedstock sourcing and energy inputs to emissions and impacts during production, transport, storage and use.
   
• Mandate best-in-class controls to prevent methane, hydrogen and ammonia leakage, ensure permanent carbon capture and storage when needed, and protect ecosystems and local communities from land-use or pollution impacts.
   
• Adopt internationally harmonized sustainability standards to avoid a patchwork of weak regulations that undermine credibility and market stability.

This disciplined approach will not only safeguard the climate — it will also deliver greater energy security, economic resilience and long-term value for industry, governments and communities alike.

Why this matters — not tomorrow, but now

The world stands at a crossroads. As energy costs surge, supply chains fray and fossil fuel volatility deepens, the case for clean fuel diversification grows stronger every day.

If we act decisively and in line with science, aligning policy, investment and environmental integrity, alternative fuels can become an integral pillar for decarbonization. They can be a cornerstone of global climate security, economic strength and energy sovereignty.

But if we cut corners, chase quick wins or ignore the details, we risk trading today’s emissions for tomorrow’s liabilities. The path forward is clear. What matters now is not just ambition, but integrity.

EDF is partnering with stakeholders to work on getting the necessary frameworks in place through, for example, our observer status at the International Civil Aviation Organization, the International Maritime Organization and other international forums.

We’re using our science-led approach to proactively find the solutions that work for the entire ecosystem, and we’re ready to engage with all stakeholders to get this right.

A version of this post was first published in EDF’s Energy Exchange blog.