Cummins: Practical Bridge Fuels and Hybrid Systems Can Cut Marine Emissions Today

Vessel owners and operators face headwinds in reducing carbon footprints: regulations and incentives vary widely between countries, while upfront costs, space constraints and weight considerations must be balanced against benefits. Even where emissions rules aren't strict, Cummins says, alternative power can deliver substantial savings from fuel and carbon costs, and a growing number of financing options — tax incentives, government and private loans, fleet renewal/retrofitting funding, and lower interest rates for greener fleets — are linked to sustainability targets. Mission contracts increasingly require evidence of carbon reduction, and practical bridge solutions can cut greenhouse gas emissions immediately with virtually zero impact on the durability and reliability of Cummins marine engines.

Cummins marine engines are approved for hydrotreated vegetable oil (HVO) and biodiesel blends up to B20 in engines without aftertreatment systems. Dual-fuel systems allow methanol, ethanol and ammonia to be explored while preserving the ability to run on diesel or drop-in replacements, though these fuels have strict storage and handling requirements. No single 'fuel of the future' has emerged yet, but options are growing: in South America, HVO and other biofuels are well understood, with ports in Brazil and Chile becoming hubs for renewable marine fuel bunkering. At least one large cargo shipping company has committed to methanol, equipping new vessels with dual-fuel technology and building fueling installations in its major ports, helping make low-carbon fuels viable for small and medium operations.

Hybrid systems combine diesel engines with a source of electric power, often rechargeable batteries, reducing emissions while maintaining operational flexibility. Since fuel accounts for approximately 70 percent of a vessel's operating expenses, diesel-electric technology can be a smart upgrade or retrofit for an existing ship. Even if batteries can't cover a vessel's entire operational profile, a smaller electric 'harbor set' can save thousands of dollars a year by allowing operation during idle or low-power periods with fewer diesel engines running, such as when loitering at anchorage or in port.

Ports offer significant chances to improve efficiency when marine assets are viewed as part of a broader operating ecosystem. Port support vessels and infrastructure like material handling equipment have more limited jobs and may be easier to transition to alternative energy than oceangoing vessels. For example, if a port has HVO fueling infrastructure for refueling boats, the same fuel could power all diesel engines in the facility, and other applications might be cherry-picked for hybridization or fully battery-electric solutions. Many ports also help operators create and submit grant applications, while evolving regional regulations, fuel availability and geopolitical factors can influence which alternative fuels are practical, making fuel flexibility important for multi-port operations.

With Cummins marine engines, operators don't need to wait for new decarbonization solutions, says the company. Bridge technologies are backed by years of operational experience and data from thousands of engines, and end users on land and sea trust their durability and reliability. The best option for each marine application is likely to vary, but greener vessels and fleets are more accessible than ever, and Cummins is committed to helping mariners find efficient, cost-effective strategies.