Expert blogs

Are hybrid electric ships the answer for a more sustainable Marine industry?

The shipping industry is under immense pressure to decarbonise. Marine vessels are responsible for a significant amount of global greenhouse gas emissions. According to the International Maritime Organisation, shipping is accountable for around 2-3% of global CO2 emissions, and is projected to increase to 17% by 2050, making it one of the largest emission sources in the transportation sector.

To mitigate the environmental impact and move towards a more sustainable future, the industry is examining different solutions, such as cleaner technologies and alternative fuels. One, which is growing in popularity, is the electrification of vessels, either through hybrid – a combination of diesel engines with electric motors and/or batteries - or with fully electric systems. One example is “Sparky”, the fully electric tugboat for the Ports of Auckland built by Damen Shipyards, which was awarded as one of the best inventions of 2022 by TIME magazine. Sparky is just one of the vessels that are setting sail for a more sustainable marine industry.

Why go electric? Advantages of electrification of marine transport

The electrification of marine vessels offers numerous advantages, such as environmental benefits, improved energy efficiency, and enhanced performance. A study published in Nature Energy suggests that over 40% of global containership traffic can be electrified with current technology.

Going electric in the marine sector can lead to a significant reduction of emissions and more sustainable vessel operations. Electric vessels do not generate greenhouse emissions during operations, which can help both reduce pollution and minimize the impact on marine ecosystems. How is this possible? The electric grid is more energy efficient than vessel engines which usually run on diesel or heavy fuel oil. Therefore, the emissions per kW of electric energy production are much lower than the emissions generated by the marine engine. Additionally, electricity costs are typically lower than the cost of marine diesel providing an OPEX savings incentive to vessel owners. 

If we take a look at the statistics, the industrial electricity price average is 11.38 euro cents per kWh (statistics from 2021), and in some regions like North America and parts of Europe the price is even lower. In comparison, global average bunker prices vary by fuel type and when converted to equivalent units are around 17.15 euro cents per kWh. This also depends on engine type and size, load conditions, etc. but looking at averages, the equivalent energy output is about 1/3 cheaper when sourced from the grid vs marine diesel.

Furthermore, the global average carbon intensity from the electric grid in 2021 was approximately 400g CO2/kWh. This varies by region, with the Americas and Europe producing a lower carbon footprint of approximately 280gCO2/kWh and Asia, Africa and Australia producing an average of 520g CO2/kWh. The average CO2 emissions from marine diesel engines vary depending on engine size, load conditions, operating modes, and the specific emission control technologies implemented by manufacturers. However, the carbon intensity is typically within the range of 600 - 900 gCO2/kWh. 

In the example mentioned above, Sparky, the fully electric tugboat designed by Damen, has eight battery packs providing a total of 2784 kilowatts hours of energy. This means that Sparky can pull the same tonnage as the Port of Auckland’s strongest diesel tugboat. Sparky is expected to save approximately 465 tonnes of CO2 in diesel emissions annually with an expected operating cost of less than a third of her diesel counterparts. Damen have also developed several types of hybrid electric water buses and city ferries with a hybrid-electric propulsion system for peak shaving, that are making short-distance marine travel and transportation more sustainable. 

Sparky electric tugboat at seaSparky, a fully electric tugboat developed by Damen Shipyards

Examining other examples, the Yara Birkeland, a fully electric and autonomous container vessel developed by YARA and KONGSBERG, is expected to remove 40000 diesel-powered truck journeys every year and reduce both nitrogen oxide and carbon emissions, road dust formation and traffic noise. The Crowley electric tugboat for the Port of San Diego is expected to eliminate the consumption of over 113,000 litres of diesel annually with an expected reduction of 3,100 tonnes of CO2 in its first 10 years of operation.

In addition to operating more sustainably, electric propulsion systems can provide greater energy efficiency, lower operational costs and increase fuel savings. The electric propulsion systems can also enhance the performance of the vessel, offer better manoeuvrability and quieter operations.

Challenges of electrification

While the advantages of electrification of the marine sector are undeniable, there are still some challenges that need to be overcome before we can expect the investment in electric or hybrid vessels to surpass the number of conventional ships.

Let’s examine some of the challenges:

  • Charging infrastructure: Issues with charging infrastructure is the first thing we hear from customers when discussing electrification of vessels. While many of our customers are interested in adopting a hybrid technology or going fully electric, their main obstacle is that the ports are not ready for this technology and do not have charging stations. So, the infrastructure is preventing shipbuilders to adopt the technology. This is where we need a key change. Establishing an accessible and robust charging infrastructure is essential for the adoption of electric vessels and ports globally need to modernise their infrastructure to incentivize the use of this more sustainable technology. 
  • Energy demand: E-vessel charging could cause spikes in energy demand. However, the vessels would only charge for a specific time during the day, and instead of using the main electric grid, ports could rely on hybrid microgrids for that extra power needed for charging.
  • Investment costs and battery technology: The cost of batteries, retrofitting or building new vessels are a serious investment. Any fully electric boat is two to six times more expensive than a comparable conventional vessel. Battery technologies have come a long way, but are still costly. The average battery prices in 2022 were €140/kWh. BNEF predicts that the cost of batteries will be reduced by 20% by 2025 which should accelerate the development and adoption of electric propulsion system

  • Technology in development: There are still a lot of unknowns and extensive analysis happening at this time to determine which vessels are suitable for electrification. Longer voyage durations will require additional energy storage or hybrid solutions, and further analysis must be undertaken to identify the types, sizes and weight of the BESS to ensure smooth sailing and uninterrupted vessel operations. 
  • Electromagnetic interference: The voltage of a DC system is typically much higher than that of an AC power plant. For example the main DC bus might be anywhere from 750 – 1000 VDC or more, whereas a conventional system is nominally 440-690 VAC. With higher voltages, the electromagnetic fields can interfere with the functionality of the vessel’s control and communication systems. One way to overcome this challenge, and the solution ComAp has utilised with some of our customers, is to mount the controls in a cabinet that is separated and remotely located from the inverters, rectifiers, and busbars. This ensures that the vessel operators can run their vessels without any interruptions, almost as if they were running on conventional AC technology. 
ComAp’s power management system accelerates the benefits for electric vessels

Following the latest trends in the industry and leveraging our expertise, ComAp has developed flexible control systems and components that bring the benefits of hybrid technology to ship owners and operators.

ComAp’s power management system can optimise the usage of different power generation sources on the vessel, depending on the energy demand load. The solution can be used for automatic synchronisation of the ship’s energy sources and shore connection while docking in the port. This includes synchronising and connecting AC sources, matching voltages and connecting DC sources, sharing the load between online sources, connecting charging facilities and charging the battery according to the state of charge of the battery.

Interested in using our power management system to help you move to a hybrid electric marine system? Check out our solutions for decarbonisation and contact us for more information. 

Our website uses cookies and similar technologies to provide you the best experience and to understand how you use our site.

You may either „Accept all“ by which you agree with using functional, analytical and marketing cookies. By pressing „Revoke“ only necessary cookies shall be allowed to enable the website and applications function correctly. To revoke your consent you can do it from footer menu in Change cookie preferences section.

You can find more information on the Cookie page and the Privacy section .