The electric marine section is in its nascent stage, set to transform considerably in the coming years. Government regulations and sustainability goals are certainly making waves. The maritime sector has charted a course to decarbonisation by agreeing to achieve net zero by 2050 with the International Maritime Organisation. However, to successfully transition the marine sector to zero emission fuels, several key questions need to be addressed: What is the most appropriate fuel for each marine archetype? Which vessels could or should transition to electric first? Will there be compromises in the performance of the vessels?

Photograph: RS Marine Group

To understand these challenges, we need to be swimming in data pertaining to the duty cycles of different types of vessels. Specifically, we need lots of information about when they are used, for how long, and how much fuel is needed.

Marine stakeholders appear to be in the same boat, after engaging with a multitude of them, it became clear that there is a lack of marine duty cycle telemetry. Often even the amount of fuel that vessels use is unclear. Details of refuelling for a vessel are seldom recorded at all and when they are, it is often in a paper logbook. Without a clear view of how a vessel is used, it is extremely challenging to assess the appropriate zero emission fuel alternative.

So, we set about developing a model to estimate fuel use of vessels from high level data. The key source of data here is the Automatic Identification System (AIS). This system automatically transmits and receives vessel information, including identity, position, speed and course. AIS is mandatory for large commercial vessels and passenger ships, although many smaller vessels use it voluntarily. Data also helps model energy demand profiles for vessels and how the availability profiles of vessels align with the energy network’s needs.

Using this AIS data as an anchor, we are developing a Voyage Energy Modelling Tool (VEMTO). The purpose of this tool is to provide an estimate of the power and energy required by a given vessel to perform a duty cycle as described by an AIS data feed. Providing a reasonable estimate of the energy required for a specific vessel and its duty cycle is crucial for transitioning to the appropriate zero emission fuel.

Photograph: RS Marine Group

VEMTO works by estimating the calm water resistance of the given vessel using the speed from the AIS data. For historical data, the local weather may not always be known. However, since the tool is to be used for high level estimates to assess appropriate technologies, a reasonable worst-case scenario for weather is assumed. An additional calculation for the energy used to compensate for wind and waves is then performed. This way we are calculating the reasonable worst-case energy consumption for the voyage. Whilst such an approach may be approximate, it offers significant advantages when compared to a simple analysis based on fuel sales, in which energy demand for individual voyages and timings of refuelling opportunities would not be known. As a byproduct of the model, we can estimate current CO2 emissions for the existing engine and duty cycle, and thus the potential savings.

Applying the VEMTO model to many different vessels and duty cycles can help us understand the energy requirements and potential carbon savings for different vessel archetypes. From this, we can start to create a roadmap for decarbonisation. With energy requirements and duty cycles clearly identified, the task of specifying charging infrastructure becomes a little easier too. Such insights will be invaluable as we chart a course for marine decarbonisation.

VEMTO model diagram:

Learn more about our work in marine decarbonisation: Setting Sail to a Greener Future: Optimising Revenue Streams for Vessel-to-Grid Charging

Interested in using the VEMTO model? Reach out to us today