Nature Energy intl_tech D1

发布：2026-05-30 · 事件：2026-05-30

Subjects Energy policy Environmental impact The IMO Net-Zero Framework promotes adoption of low climate impact marine fuel through combination of pricing mechanism and fuel standard; however, fuel cho...

Subjects Energy policy Environmental impact The IMO Net-Zero Framework promotes adoption of low climate impact marine fuel through combination of pricing mechanism and fuel standard; however, fuel choice depends on competition for clean energy across sectors. Policies must consider life cycle perspective to avoid shifting impacts to the fuel supply chain and address wider environmental impacts, including land use and mineral resource depletion. Messages for policy Shipping policies that adopt pricing only on exhaust emissions (for example, a tank-to-wake levy) without a life cycle perspective risk increasing life-cycle climate impact. The proposed IMO Net-Zero Framework is an important step for shipping decarbonization but stricter greenhouse gas fuel intensity levels are needed to meet the net-zero emission target. Policies should support the development of bioenergy with carbon capture and storage, as negative emissions influence future fuel choices in shipping. Stricter regulation on nitrogen oxides and nitrous oxide is crucial to avoid unintended environmental issues as ammonia emerges as a cost-effective fuel option in several cases. Shipping decarbonization should address wider environmental trade-offs, including land use and mineral resource depletion, to avoid unintended burden-shifting. You have full access to this article via your institution. Download PDF based on Kanchiralla, F. M., Brynolf, S., Hansson, J. & Grahn, M. Nat. Energy https://doi.org/10.1038/s41560-026-02079-6 (2026). The policy problem Shipping-specific policies are important to meet the greenhouse gas (GHG) emission reduction targets set by International Maritime Organization (IMO). The proposed “IMO Net-Zero Framework” (NZF) approval was postponed in October 2025, and other policy designs are being discussed. The NZF includes two mechanisms: first, a greenhouse gas fuel intensity standard (GFI) that includes a life cycle perspective; and second, a pricing mechanism for GHG emissions. Increased understanding of how different policy architectures, including the NZF, will drive the transition of the shipping sector, and whether these policy architectures create unintended risks such as shifting to fuels with high upstream emissions, is essential for effective regulation and ongoing policy discussions. The availability of low-climate-impact fuels is another key aspect. However, this is not determined by shipping policy alone but depends on the development of the wider energy system, including total demand and competition for renewable electricity and biomass across sectors. The findings Climate policies are needed to drive decarbonization of the shipping sector. Our assessment of different shipping policies confirms that it is critical to have a life cycle perspective on the GHG emissions to avoid shifting emissions upstream and to reduce net emissions from shipping. The cost-effective choice of marine fuel under different shipping policies is closely linked to competition from other sectors in the energy system such as biomass availability. The NZF promotes biofuel adoption in shipping, but with cross-sector competition for biomass under climate targets, ammonia produced from renewable electricity and biomass might play an important role for several shipping segments, while electrification is preferred for vessels with daily bunkering possibilities (Fig. 1 ). However, this transition risks increasing other environmental impacts, including land use and mineral resource depletion. The implementation of policies with a standalone economic policy (for example, levies) without a life cycle perspective has a substantial risk of increasing life cycle climate impact from shipping. Fig. 1: Cost-effective fuel and technology choices for global shipping under different policies and climate targets. The alternative text for this image may have been generated using AI. Full size image Each panel shows the share of energy from different fuels (outer circle) and powertrain (inner circle) for global shipping for the years 2040 and 2060 under three policy scenarios with and without a global 2 °C climate target. Under a scenario without a global climate target, a marine levy on tank-to-wake emissions without a life cycle perspective favours grey ammonia that has a high climate impact in fuel production. Under the IMO Net- Z ero Framework, without a global climate target, biomethanol becomes cost-effective whereas ammonia is found to be a cost-effective choice in most cases; the ammonia production pathway depends on both shipping policy and climate target. Figure adapted from Kanchiralla, F. M., Brynolf, S., Hansson, J. & Grahn, M. Nat. Energy https://doi.org/10.1038/s41560-026-02079-6 (2026). The study This study uses a global energy system optimization model to evaluate six different shipping policy scenarios. The model represents the entire global energy system to determine cost-effective pathways under different constraints and policies by optimiz