Various paths to support decarbonisation include alternative carbon-free and carbon-neutral fuels, electrification and enhancing vessel efficiency. A system level approach enhances the value of these technologies; tackling each element separately can lead to a sub-optimised solution today and an inflexible solution to meet the uncertainties and increasingly stringent requirements in the future.
Wärtsilä Marine set up its Integrated Systems & Solutions (IS&S) unit to address these challenges. The team brings together expertise in naval architecture, energy management and electrification, power system design and simulation, and multi-product integration to design, engineer and deliver competitive and future-proof propulsion concepts.
Data-driven design principles
The 50-strong IS&S team at Wärtsilä engages with customers from concept development to commissioning
Since its establishment in 2020, the 50-strong IS&S team at Wärtsilä engages with customers from concept development to commissioning.
They apply data-driven design principles by analysing operational data against customer objectives to define system specifications that balance performance, operational expenditures (OPEX), capital expenditures (CAPEX), and future flexibility.
Secondly, they employ modular integration by configuring pre-engineered building blocks, such as engines, batteries, propulsion, and power-management software to the needs of each vessel, thus reducing yard workload and ensuring interoperability.
Encompass carbon-neutral fuels
“In today’s rapidly changing maritime environment, flexibility, system intelligence and digitalisation are essential,” says Grant Gassner, Director, Integrated Systems and Solutions at Wärtsilä Marine.
He adds, “We at Wärtsilä are committed to delivering comprehensive, upgrade-ready powertrain platforms that encompass carbon-neutral fuels, advanced electrification and new efficiency technologies and are committed to supporting the customer throughout the entire lifecycle towards net zero.”
Ensuring agility to adapt to regulations
The maritime industry currently struggles with a lack of availability and high cost of sustainable fuels
As regulatory requirements become increasingly clear through the framework established by European Union (EU) and International Maritime Organization (IMO), analysing potential compliance strategies and roadmaps ensures a power system that is agile and able to adapt to evolving fuels, technologies, regulations, and vessel operational trends, says Gassner.
The objective is to ensure a flexible path forward by enabling an optimised total cost of ownership (TCO) as well as reducing the risk of stranded assets.
The maritime industry currently struggles with a lack of availability and high cost of sustainable fuels. Engine technology is available to use these fuels, which is good news; however, a somewhat unclear regulatory environment so far has made it challenging to secure large scale investments to develop sustainable fuel projects.
Net-zero regulations for shipping
It is therefore encouraging and positive that the April 2025 Marine Environment Protection Committee (MEPC 83) session approved a framework for net-zero regulations for shipping, which is expected to be formally adopted in the October 2025 IMO extra-ordinary MEPC.
A clearly defined regulatory environment that includes a relatively high and increasing cost of carbon emissions is a fundamental prerequisite to accelerate investments and progress.
Tailoring solutions globally to owners and operators
Wärtsilä’s decarbonisation approach is designed to tailor flexible solutions to the unique needs of owners
Wärtsilä’s decarbonisation approach is designed to tailor flexible solutions to the unique needs of owners and operators globally, ensuring that they are equipped with the right technologies, at the right time.
“As a company, we do not just sell a product or technology, we offer a partnership,” says Grant Gassner, adding “We want to partner with our customers to help them transition at the right pace, at the right time.”
The most topical talking point at Nor-Shipping in June was around the framework IMO approved in MEPC 83 regarding net-zero regulations for global shipping. Although there remain some uncertainties, the consensus around the proposal is that it is a highly significant and important development.
Incentivise marine decarbonisation
“It finally provides some regulatory clarity and attaches a significant lifecycle cost to carbon emissions, which is a fundamental prerequisite to incentivise marine decarbonisation and also stimulate investment in fuels infrastructure and new technologies,” says Grant Gassner.
He adds, “The IMO should be commended for achieving this breakthrough approval during MEPC 83. The legislation framework provides a renewed sense of optimism within the maritime community that we will observe real progress in the coming years in a segment that is highly challenging to abate.”
Lifecycle power solution and service partner
Wärtsilä’s role has expanded from equipment supplier to a complete lifecycle power solution partner
Wärtsilä was established over 190 years ago in 1834 as a sawmill and transitioned into iron works in the decades leading up to 1940.
Over the decades, their marine offering has expanded from the first engine manufactured in 1942 into a complete powertrain systems and digital service offering, collaborating closely with shipyards and owners worldwide.
Today, as the industry shifts towards decarbonisation, Wärtsilä’s role has expanded from equipment supplier to a complete lifecycle power solution and service partner, bringing together engines, electrification, propulsion, software, and lifecycle services.
Addressing a significant new lifecycle cost
Traditional power system design philosophy has historically focused on optimising the TCO based on a relatively certain and fixed regulatory environment, fuel, and technology selection over the lifecycle of a vessel.
However, in 2025, the evolving regulatory environment around decarbonisation incorporates a significant new lifecycle cost attached to carbon emissions, requiring a totally new approach.
Ship owners and operators must now consider the evolving needs of a vessel to continuously reduce carbon intensity over the typical 25–30-year vessel lifecycle. They also must consider the uncertainty of how to mitigate potentially significant costs.
Generational new challenge
“This generational new challenge requires a propulsion system that is not only competitive today, but which also has the capability to continuously adapt,” says Grant Gassner.
He adds, “This will ensure a competitive TCO over the lifecycle of a vessel against a backdrop of a highly uncertain future regarding the available fuels, technologies, and evolving regulations.”
Advantages of single-supplier accountability
Future lifecycle upgrades can include sustainable fuel retrofits in the future, hybrid systems
Wärtsilä’s single-supplier accountability model means that, as the OEM, they own both equipment and interfaces. This approach simplifies project execution and risk management for customers.
Their solutions also benefit from lifecycle support and the capability to adapt their products continuously. Future lifecycle upgrades can include sustainable fuel retrofits in the future, hybrid systems and shore connections, energy-saving devices, or enhanced digitalisation.
Wärtsilä focuses on fuel flexibility, electrification and/or energy efficiency improvements and considers them holistically within a hybridised system rather than in individual silos, since they all significantly influence the overall power system and its design.
Wärtsilä’s engine portfolio
Wärtsilä’s engine portfolio was developed decades ago to operate on a range of marine liquid fuels and LNG, both in fossil and bio-fuel form.
They have also commercially released engines capable of running on emerging low- or zero-carbon fuels such as green methanol, ethanol, ammonia and hydrogen.
“It is, therefore, safe to conclude that engine technology will not delay the uptake of sustainable fuels,” says Grant Gassner.
Sustainable fuels will be more expensive
There is no broad consensus in the marine industry on which sustainable fuel will prevail
Currently, there is no broad consensus in the marine industry on which sustainable fuel will prevail in the journey toward decarbonisation; most likely, several fuels will contribute.
In any case, there is general agreement that all sustainable fuels will be significantly more expensive than traditional fossil maritime fuels and that availability will remain uncertain for the foreseeable future.
The high cost and scarcity of sustainable fuels will therefore drive an unprecedented focus on improving vessel energy efficiency. After all, the cheapest fuel is the one you do not burn.
Propulsion power systems
Efficiency gains will come from a range of new technologies, such as wind-assisted propulsion, hull air lubrication, enhanced hull forms and propulsion concepts, smart digital navigation systems and further reductions in vessel speed, commonly known as slow steaming.
These advances will also affect propulsion power systems, so a holistic approach to ship design and power-system integration has never been more important in light of increasingly hybridised propulsion concepts.
The fundamental role of electrification
Although much of the discussion in the marine industry rightly centres on sustainable fuels
Although much of the discussion in the marine industry rightly centres on sustainable fuels, electrification will also play a fundamental role in the transition to net zero.
All vessels operating over short distances, regardless of size, will increasingly adopt battery-electric propulsion, combining sizeable battery banks with plug-in shore connections as their primary energy source, says Gassner.
This battery-electric solution offers far superior “grid-to-wake” efficiency compared with producing e-fuels from renewable electricity, bunkering those fuels, and then reconverting them back into mechanical or electrical energy via a thermal converter such as an engine.
Battery technology and shore-power infrastructure
Today, many Roll-On/Roll-Off Passenger (ROPAX) ferries covering distances of up to 100 nautical miles are already shifting from traditional mechanical drives to hybrid-electric drivetrains: Medium-speed 4-stroke generating sets feed electricity into a hybrid system with large, scalable energy-storage capacity and a fully electrified propulsion line.
As battery technology and shore-power infrastructure advance, these vessels will rely ever more on green shore electricity and ever less on gensets running on bunkered fuels. Such applications will soon exceed 100 MWh of installed battery capacity, which is enough to meet much of the power demand of today’s regional ferries and short-sea vessels.
Wärtsilä has already partnered with Australian shipbuilder Incat and Argentinian operator Buquebus as system integrator for the world’s largest zero-emission fully electric catamaran. Set for delivery in 2025, the vessel will feature approximately 40 MWh of energy storage, measure 130 metres in length and carry 2100 passengers plus 225 vehicles.
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| Argentinian operator Buquebus as system integrator. |
Role of electrification
There is growing interest in deep-sea segments, such as LNG carriers and containerships
The role of electrification in deep-sea shipping has often been overlooked, given the currently valid consensus that such vessels demand too much energy to run on batteries alone today or in the near future.
As a result, it has been assumed that deep-sea propulsion solutions will remain largely unchanged and that available green fuels will materialise when needed. However, there is growing interest in deep-sea segments, such as LNG carriers and containerships to adopt hybrid-electric propulsion.
Hybrid-electric is compact and fuel-agnostic
Hybrid-electric propulsion is fuel and technology agnostic: A modular hybrid-electric drive can easily accommodate all new fuels and powering technologies. Another advantage is compactness and cargo gain as enhanced design flexibility can increase cargo capacity by around 6-7% in modern LNG carriers, reducing carbon emissions on a grams per ton per mil basis.
New fuels can be introduced incrementally (one small genset at a time), while the electrical system buffers dynamic load changes and can adapt to potential changes in engine performance properties when applying new fuels, such as power output and dynamic loading.
Deep-sea shipping segments
Furthermore, modular systems maintain high load factors and thus high efficiency even at low power nodes
Furthermore, modular systems maintain high load factors and thus high efficiency even at low power nodes, pairing well with energy-saving measures and slow steaming.
Greater redundancy, built-in safety and readiness for autonomous operation and zero-emission fuels and low underwater radiated noise contribute to further safety and futureproofing. Electric propulsion has been reliably used in cruise and offshore segments for decades, with thousands of installations worldwide.
In view of these factors, deep-sea shipping segments may gradually transition towards ever more electrified and hybridised drivetrains, initially via hybrid mechanical PTO/PTI concepts and ultimately to full hybrid-electric systems with propellers driven by electric motors rather than mechanical low-speed engines.
Flexibility needed for uncertain future
“Data-driven design” is an important factor when it comes to developing maritime solutions. “By drawing on real-world operating profiles, fuel consumption records and voyage data, we tailor each integrated system to actual customer needs,” says Grant Gassner.
Furthermore, system simulation models need to consider new factors such as emission penalties, costs of sustainable fuels, and developments in regulatory requirements over time. These factors make propulsion system models increasingly complex in order to evaluate total lifecycle cost analysis which includes a new variable: the cost of carbon, which was not previously considered in the past.
Power system simulation, energy management, AI, and electrification combined with deep knowledge in naval architecture and marine engineering are critical competences for the future. There is also a need to follow closely new electrification technologies such as fuel cells, solar, nuclear heat to power, ESS, etc., as new technologies may also play a role in hybridised next generation propulsion concepts.
Modular electrified systems
In an uncertain regulatory, technology and fuel-supply landscape, flexibility is vital in order to “future-proof”
In an uncertain regulatory, technology and fuel-supply landscape, flexibility is essential in order to “future-proof” the approach.
Engines running on LNG today can be made ready for ammonia tomorrow, and modular electrified systems can be upgraded with more batteries, new powering technologies and can also adapt to lower power demand as a result of efficiency saving technologies.
“We design our solutions so they can be upgraded over time, and our lifecycle service agreements cover asset management, software updates and retrofits,” says Grant Gassner, adding “This approach keeps vessels compliant, efficient and resilient throughout their service life.”
From newbuilds to vessels in service
For newbuilds, IS&S explores dual-fuel engines, battery banks and renewable generators as part of the ship’s design from the very start. Wärtsilä provides detailed functional specifications and pre-engineered modules to simplify installation.
Wärtsilä provides detailed functional specifications and pre-engineered modules to simplify installation
The software underpinning any hybrid propulsion system is of course also crucial, which is why the energy management capabilities of Wärtsilä are important for ensuring the efficiency, reliability and flexibility of the solution adopted.
For vessels already in service, Wärtsilä’s retrofit solutions enable customers to install batteries or extra fuel-flexible engines into available spaces, reconfigure switchboards and update control software.
Over the entire vessel lifecycle
Although retrofits can be more complex because of space limitations and structural constraints, their modular approach and single-supplier project management keep the work on schedule and within budget.
The capability to support owners over the entire vessel lifecycle will be of utmost importance going forward and therefore, a holistic lifecycle view is fundamental when developing today’s propulsion concepts.
