Some of the world’s leading green fuel producers have called on delegates at the International Maritime Organisation (IMO) to seize a “once-in-a-generation” opportunity to set shipping on a sustainable pathway.

As delegates gathered for an extraordinary session to discuss the adoption of the IMO’s Net Zero Framework (NZF) 27 fuel producers sent an open letter urging the organisation to toughen its stance.

The NZF was agreed in April earlier this year and a final vote is expected by Friday, and the letter written by European clean energy group Transport & Energy (T&E) has pushed the IMO to be more stringent in the framework’s terms.

The group of companies, including European Energy, Liquid Wind, ET Fuels, HIF Global and Zero Waste has urged the IMO to adopt the deal and to include specific incentives for green e-fuels which are currently at a disadvantage to LNG and biofuels. That is despite hydrogen-based e-fuels providing much greater emissions savings and being the only fuel that cannot. Together the signatories have projects in Africa, South and North America, Europe, South Asia as well as Oceania.

Dr Alison Shaw, IMO manager at T&E, said: “E-fuel producers need policy certainty to get green shipping fuels off the ground. Shipping could become a major offtaker for hundreds of projects worldwide, but only under the right rules. The current IMO Net-Zero Framework leaves e-fuels competing with cheaper and unsustainable options like fossil gas and first-generation biofuels. The message from producers is clear: to decarbonise shipping at scale, incentives for green e-fuels are essential. Without targeted incentives, shipping’s energy transition risks stalling before it begins.”

The letter states: “The NZF is a critical step forward as a policy signal for the energy transition of international shipping and we welcome its adoption in October 2025.

“That said, significant work remains to ensure the reduction of GHG emissions aligned with the IMO 2023 Strategy. The NZF’s effectiveness now depends on how the implementation Guidelines are designed and what signals policymakers choose to embed within them.

“In the view of the signatories, the current framework does not provide sufficiently strong investment signals for e-fuels.”

It cautioned: “The NZF, as currently drafted, and without additional prioritisation for e-fuels in the relevant implementation Guidelines, risks incentivising pay-to-pollute strategies while also stimulating investment in transitional fuels, such as LNG, first-generation biofuels, and blue fuels.

“This would leave scalable zero-emission e-fuels under-incentivised from a regulatory standpoint and would delay large-scale deployment of the only long-term zero-emission fuels capable of delivering deep reductions aligned with the IMO 2023 Strategy.

“Without immediate and unambiguous signals for the production and uptake of e-fuels, the global fleet risks ‘locking in’ short-term fuel pathways that undermine both ambition and cost-effectiveness over time.”

T&E added globally, there are an estimated 73 million tonnes per year of green hydrogen production planned for 2030, yet only 13% of these volumes are linked to offtake agreements.

“In the absence of stronger policy signals, many of these green hydrogen projects may struggle to reach Final Investment Decision (FID) and thus fail to become operational,” the letter added. “This is a challenge shared by all e-fuels as the dynamics seen in green hydrogen mirror those across the wider e-fuels landscape.

“If the IMO NZF were to place greater emphasis on green e-fuels uptake, it would provide the necessary demand certainty to unlock investment and ensure the maritime sector’s transition stays on track.”

The letter concluded: “The NZF is a once-in-a-generation opportunity. By sending clear and durable signals in favour of scalable zero-emission e-fuels, the IMO can ensure that international shipping is not only on track to transition its fuel mix to reduce GHG emissions, but that it does so in a cost-effective and sustainable way.

“Without these calibrations, the NZF risks under-rewarding the very fuels that can deliver deep decarbonisation at scale.”