Wartsila: Key trends surrounding hybrid vessels

• small merchant vessels
• PCTCs
• RoRo and RoPax ferries
• smaller ferries
• special vessels like tugs and research ships and even
• large container vessels

How do hybrid ships work?

Hybrid electric ships have a battery and a conventional combustion engine. A hybrid ship can instantly switch between engine and battery when required, or the engine and battery can be used simultaneously. The battery is used in one of two ways:

• For optimizing the propulsion train – the battery is used for functions like spinning reserve, peak shaving, black out prevention or load ramp-up support
• For zero-emission sailing – the battery provides 100% of the power for the vessel in maneuvering or harbor operations.

The seven hybrid trends to look out for

As informed, experts predict that the coming years will see:

• New battery types
• More powerful batteries
• Batteries being chosen based on function, not size
• The addition of fuel cell technology such as solid oxide fuel cells (SOFCs)
• More DC hubs – which might not always be the right choice
• More ports offering shore power
• Even more hybrid retrofits in the ferry segment

There are four main benefits of hybrid ships

In addition, Wartsila notes that hybrid vessels come with certain benefits, including the following:

1. Hybrid ships lower fuel and maintenance costs and are more efficient than diesel-powered ships.
2. Hybrid ships are better for the environment, with up to 25% lower emissions than comparable diesel-powered vessels. This makes it easier to comply with strict emissions regulations and makes the vessel more attractive for charterers or passengers.
3. When running on battery power, your ship will generate less noise and vibration, so the journey is quieter and more comfortable for passengers and crew. Less noise and lower emissions also have a positive impact on coastal communities and ecosystems.
4. If a hybrid ship’s batteries are charged using shore power, the electricity already comes from up to 50% renewable sources.

Trends surrounding hybrid ships

1. New battery types are becoming available

All marine batteries are lithium-ion batteries, similar to ones from the automotive and energy industries. Now we’re starting to see the introduction of new lithium-ion battery chemistries for use on ships.

In the past, nickel-manganese-cobalt (NMC) batteries were the standard for maritime applications, but now lithium-ferro-phosphate (LFP) batteries are rapidly becoming the default choice. Another emerging battery type for ships is lithium-titanium-oxide (LTO) batteries.

According to IEA’s analysis, the global lithium-ion battery market surpassed USD 150 billion in 2025, highlighting batteries’ expanding role.

2. Batteries are becoming more powerful

In the past, batteries on hybrid ships were mostly used for spinning reserve, where the battery provides the entire load for the application. For example, the auxiliary genset would be turned off and the battery would provide the power for station keeping in offshore applications. Batteries were smaller and they were also used for peak shaving and ramp-up support.

Today’s marine batteries of up to 54 MWh make it possible to achieve zero-emission operations. A marine battery with this level of capacity can also provide power for the ship during harbor stays.

However, the size of the battery in a hybrid ship is not the only important factor to consider. The right battery for each ship depends on how it will be used and the operating profile of the vessel.

Lower prices are not the reason for the trend of more powerful batteries alone. The steady decline in battery prices seen prior to 2020 has slowed down. With the increasing global demand for the cells and their raw materials, the price of marine batteries for hybrid ships is not likely to fall further.

3. Battery function is more important than battery size

Battery function is more important than battery size because the battery on a hybrid ship helps optimize the propulsion system, so its ideal size depends on the vessel’s operational profile. Different modes make it possible for the vessel operator to choose the most efficient way to run the propulsion system. For example, when shore-side charging is required, sailing considerations are not as important for battery sizing as charging time and capacity.