Flex-fuel shipping: Designing and operating commercial ships to meet climate targets

The marine shipping industry, responsible for about 3% of global GHG emissions, is under pressure to decarbonize following new targets from the EU and the IMO. The Clean Air Task Force (CATF) highlights that dual-fuel engines, which can run on conventional fuel as well as alternatives like methanol and ammonia, are becoming a standard design to provide flexibility over a ship's 30-plus-year lifespan. CATF's analysis indicates that ammonia-fueled ships could nearly fully decarbonize at a lower lifetime fuel cost than heavy fuel oil if carbon pricing is in place. To achieve these goals, the document recommends a clean marine fuel standard that mandates minimal upstream emissions, ensures safe bunkering, requires on-board pollution controls for gases like nitrous oxide, and uses economic incentives like a low carbon fuel standard to manage the higher costs of zero-emission fuels.

• The International Maritime Organization (IMO) has updated its emissions goals to reach net-zero by "close to 2050," with interim reduction targets of 20-30% by 2030 and 70-80% by 2040.
• Dual-fuel engines capable of using alternative fuels such as methanol and ammonia are expected by major manufacturers MAN and Wartsila to become the standard design within a few years, allowing operators to pivot to alternative fuels as they become available.
• Analysis by CATF suggests that under carbon pricing policies like the EU Emissions Trading System, ships fueled by ammonia could achieve nearly full decarbonization with lower overall lifetime fuel costs compared to conventional low sulfur heavy fuel oil.
• To ensure genuine decarbonization, a clean marine fuel standard must require minimal upstream emissions, including the verification of methane leaks and carbon capture for hydrogen and ammonia produced from natural gas, and the use of additional, matched zero-emission electricity for e-fuels.
• Operational changes, specifically reducing shipping speeds by 10-30%, can lead to a 20-50% reduction in fuel consumption regardless of the fuel type used.

APA

Steelman, J. (2024). Flex-fuel shipping: Designing and operating commercial ships to meet climate targets. Clean Air Task Force. https://www.catf.us/2024/01/flex-fuel-shipping-designing-operating-commercial-ships-meet-climate-targets/

Chicago

Steelman, John. Flex-fuel shipping: Designing and operating commercial ships to meet climate targets. Clean Air Task Force, 2024. https://www.catf.us/2024/01/flex-fuel-shipping-designing-operating-commercial-ships-meet-climate-targets/.

Wikipedia

{{cite report |last1=Steelman |first1=John |title=Flex-fuel shipping: Designing and operating commercial ships to meet climate targets |publisher=Clean Air Task Force |date=18 January 2024 |url=https://www.catf.us/2024/01/flex-fuel-shipping-designing-operating-commercial-ships-meet-climate-targets/ |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{steelman2024flexfuel, author = {Steelman, John}, title = {{Flex-fuel shipping: Designing and operating commercial ships to meet climate targets}}, institution = {Clean Air Task Force}, year = {2024}, month = jan, url = {https://www.catf.us/2024/01/flex-fuel-shipping-designing-operating-commercial-ships-meet-climate-targets/}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }