Maritime sector faces systemic barriers to green fuel transition amid finance and infrastructure gaps

A new assessment of the maritime sector’s energy transition paints a picture of progress constrained by structural bottlenecks rather than technical impossibility. While engine and shipboard technologies exist to run on methanol, ammonia and hydrogen-derived fuels, the wider ecosystem , fuels, finance, regulation and port infrastructure , remains undeveloped, creating interlocking obstacles that threaten to slow decarbonisation ambitions across deep-sea trades.

According to a study discussed in The Maritime Executive and conducted by Accelleron, five systemic deadlocks are at the heart of the problem: a fragmented set of fuel options that scatters investment; the centralised nature of large-scale e-fuel production that complicates global supply; chronically low capital allocation to shipping’s green transition; regulatory frameworks that lag policy goals; and the daunting cost for ports to provide bunkering and storage for multiple fuel types. Accelleron’s chief executive, Daniel Bischofberger, frames these factors as mutually reinforcing, arguing that cross-sector collaboration will be essential if shipping is to make meaningful progress.

The finance gap is stark. Industry analysis referenced by the study estimates shipping has attracted roughly $14.5 billion of a potential $3.5 trillion in available ESG financing for decarbonisation, underscoring a mismatch between ambition and capital flows. Closing that gap matters because the scale of required investment is vast: transitioning to hydrogen-based e-fuels for shipping alone would demand about 100–150 million tonnes of hydrogen per year and some $2–3 trillion of investment; when combined with aviation, steel and other hard-to-abate sectors the figure rises to 500–600 million tonnes and about $9 trillion, illustrating why no single industry can build the supply chain in isolation.

Supply-side constraints are already shaping policy debates in other jurisdictions. Transport & Environment’s analysis of European targets shows green hydrogen and e-fuel production remain at nascent levels, with only the first large-scale maritime e-fuel plant recently operational, signalling that policy incentives will be pivotal if FuelEU and similar rules are to be met. Complementary research from the UCL Energy Institute and UMAS recommends a mix of targeted subsidies and a significant greenhouse gas levy to tilt economics in favour of e-fuels; without such measures the commercial premium on zero-emission fuels risks producing a “feasibility wall” for green corridors and early-adopter routes.

Operational and technical mitigation measures offer a pragmatic bridge during the 10–15 year transition period. Industry analyses indicate biofuels can contribute immediately though their long-term scalability is limited by feedstock competition; LNG provides an approximate 30 percent CO2 saving versus conventional heavy fuel oil; and a suite of energy-efficiency technologies , from air lubrication and wind-assist devices to hull-form optimisation and waste-heat recovery , can deliver substantial reductions if widely deployed. DNV’s recent work stresses that a portfolio approach is likely, with biofuels, improved vessel efficiency and a mix of alternative fuels all playing roles rather than any single silver-bullet solution.

Ports are a critical chokepoint. Retrofitting terminals for ammonia, methanol, hydrogen and potentially cryogenic fuels will require large capital programmes and new safety and regulatory regimes, complicating roll-out particularly in less well-capitalised regions. Some Asia-Pacific jurisdictions are attempting to move ahead regardless: government-led initiatives in Australia, Japan, Korea, Singapore and China are promoting production, pilot plants and port facilities, and strong trade corridors such as Australia–China are facilitating early cross-sector demand aggregation. According to the Accelleron analysis, regional action demonstrates that progress need not await perfect global rules, but international frameworks remain necessary to scale solutions and prevent fragmented standards.

Regulation will be decisive. Industry and academic reports converge on the need for policy packages that both penalise fossil carbon and subsidise nascent e-fuels , for example by applying CO2 levies to make incumbent fuels less competitive while using targeted support to reduce renewable fuel costs through deployment and learning-by-doing. Without such interventions, the market signals that would justify large industrial investments in electrolyser capacity, ammonia synthesis and fuel distribution networks are unlikely to materialise at the pace required.

Technology choices will also shape capital allocation. Accelleron positions combustion engines as a durable platform for net-zero fuels, noting practical constraints on batteries for ocean-going ships and the social and regulatory hurdles that limit broader appetite for nuclear propulsion. Fuel cells remain technically promising but will take time to scale and integrate. The consequence is that e-fuels used in combustion engines could become the pragmatic backbone of deep-sea decarbonisation, provided supply costs fall , analysts forecast that, with scale and policy support, e-fuel prices might compress to two to three times current bunker prices from much larger multiples today.

For industrial stakeholders focused on decarbonisation, the immediate priorities are clear: accelerate deployment of efficiency technologies and operational measures to cut near-term emissions; pursue cross-sector partnerships to aggregate demand and de-risk initial production; and press for coherent policy instruments that combine carbon pricing with targeted subsidies to unlock the investment case for e-fuel scale-up. Absent a coordinated approach that aligns ports, energy producers, shippers and policymakers, early movers risk facing prohibitive cost premiums while late movers confront stranded-asset and regulatory risk.

The picture that emerges is one of an industry at a crossroads , technically capable of running on low- and zero-carbon fuels but politically and financially reliant on a concert of interventions beyond shipyards and engine rooms. If governments adopt the kind of fiscal and regulatory frameworks urged by academics and industry analysts, and if private capital can be mobilised at scale, shipping’s pathway to net zero could accelerate. Otherwise, the sector risks a prolonged, fragmented transition during which available gains from efficiency and near-term low-carbon options will prove critical to meeting interim climate targets.