Meeting the targets set out in the IMO’s July 2023 revised strategy for GHG emission reductions from ships demands an acceleration in the production, distribution and adoption of zero-emission fuels that can only be achieved by coordinated action, according to a new White Paper from ClassNK.

Among other objectives, the IMO strategy targets a reduction in GHG emissions of at least 20% by 2030 compared with a 2008 baseline, while also calling for zero- and near-zero emissions fuels to account for at least 5% of international shipping’s total energy consumption by the same year.

Yet according to “Pathway to Zero-Emission in International Shipping – Understanding the 2023 IMO GHG Strategy”, 5% will not be enough to meet the indicative checkpoints for GHG emissions included in the 2023 IMO GHG Strategy; ClassNK suggests 25% is necessary instead.

Published to energise maritime decarbonisation discussions among stakeholders, “Pathway to Zero-Emission in International Shipping” urges significant and prompt development of the supply chain for zero-emissions fuels. The White Paper examines the allowable lifecycle GHG emissions for international shipping, identifying the volume of zero- and near-zero emissions fuels, specifically green methanol and green ammonia. It also projects the number of compatible ships that will be required to achieve the strategy’s indicative checkpoints of at least 20% reduction by 2030 and 70% reduction by 2040.

Analysing ships of 5,000 gt and above engaged in international voyages, ClassNK reveals that a 5% share of zero- and near-zero emissions fuels — equivalent to 21m tonnes in the case of green methanol and 23m tonnes in the case of green ammonia — would yield no reduction in carbon dioxide-equivalent (CO2-eq) emissions by 2030 compared to the 2008 baseline.

Rather, a 25% share of zero-emissions fuels — 106m tonnes of green methanol or 114m tonnes of green ammonia — would be needed to achieve a 20% reduction in GHG emissions by the target year. To achieve the 2040 indicative checkpoint, three times more than the 2030 zero-emission fuels would be required.

In a further reality check, ClassNK points out that much of the methanol and ammonia produced today is derived from natural gas, and so is not emissions-free over its lifecycle. In fact, the current production volume of such methanol and ammonia across all sectors amounts to just 100m–200m tonnes per year. Considerable investment is therefore needed to expand the production and distribution of green methanol and/or green ammonia.

ClassNK’s study also indicates the necessary number of vessels propelled by zero-emission fuels. To meet IMO’s 2030 indicative checkpoint, the newbuilding and retrofit capacity between 2027 and 2030 would have to reach an annual 85m gt.

As an alternative to methanol and ammonia, biodiesel offers some potential as a low-emissions fuel that can generally be used with little or no engine modification, meaning its adoption does not rely on the introduction of specially built or retrofitted vessels, ClassNK notes.

Today, however, current biodiesel production capacity stands at just 42m tonnes per year, most of which is for land-based sectors. Production and distribution would need to increase significantly to align with ClassNK analysis, which suggests that the IMO’s 2030 indicative checkpoint would be achieved if biodiesel accounted for 29% of total maritime energy consumption (equating to 66m tonnes).

If shipping is to address its substantial shortfall in zero-emissions fuels and compatible ships in the time frame afforded by the 2023 IMO GHG Strategy, ClassNK asserts that the early adoption and implementation of a supporting regulatory framework, including effective carbon pricing, will be essential. Equally important is collaboration within and beyond the maritime industry, bringing in shippers, international organisations, national governments, the energy sector, and the financial sector.

For its part, ClassNK continues to prioritise support for sustainable shipping, and to evolve the “Zero-Emission Transition Support Services” which help customers deal with the challenges they encounter when managing GHG emissions. The classification society sees its new white paper as part of that process: as a new initiative designed to stimulate dialogue, ClassNK adds that it also welcomes opportunities to update its latest analysis based on input from other stakeholders.

Download the White Paper, “Pathway to Zero-Emission in International Shipping – Understanding the 2023 IMO GHG Strategy”, here.