Computing fuel and carbon savings in Syroco Live

Syroco Live provides weather routing and voyage optimisation to improve the energy efficiency of a vessel and decrease her fuel consumption and carbon emissions. At any point during a voyage, the on-board interface provides recommendations to the crew on the most appropriate heading, speed, power settings, etc. of the vessel, taking into account the actual and forecasted weather on the route. 

An important information is provided to the vessel master when suggesting a route update: the fuel and emissions savings associated with the route. Similarly, when a navigation report is delivered to the master or the fleet manager after voyage completion, this report presents the fuel and emissions savings (and provides in depth analysis of the savings factors). 

Establishing the reference

We are oftentimes asked how these savings are computed, what the reference or baseline is. Since two voyages, even on the same segment, are never identical (different path, different speed profile, different dates, different weather conditions…), it is very difficult to compare a current/recent voyage to a past voyage. 

In order to work with comparable elements, Syroco Live computes different types of routes:

  • The reference route is built using the sea passage plan provided by the master prior to departure, scored conservatively with a constant speed to reach the desired time of arrival. This is what the ship would do ideally without Syroco. 
  • The actual route is what happens in reality. It is built using the history of positions of the vessel.
  • The optimised route is provided by Syroco Live, taking into account the routing objectives and the operational limits of the vessel. This is the route that has been recommended by Syroco through the on-board interface.
  • Optionally, Syroco can compute a reanalysed route, which is the ideal route in light of hindcast weather (see below). 

While the reanalysed and optimised routes should theoretically be similar, they can differ because of two factors: poor adherence to the optimised route which caused Syroco to recompute a new route from a sub-optimal intermediate start point; and/or significant differences in forecasted and actual weather conditions. 

Computing fuel consumption and carbon emissions

For each of the routes described above, Syroco Live uses the digital twin of the vessel and granular weather information (provided by our partner Spire Global). During the voyage, actual and forecast weather is used. After the voyage, Syroco uses hindcast weather data: recomputed actual weather conditions, based on past observations. It is very important to obtain identical granularity and accuracy for forecast and hindcast weather, otherwise the calculations would be hard to compare. 

By virtually sailing the digital ship on each of the routes with associated weather, Syroco Live computes accurately the fuel consumed and the carbon emitted by the vessel on this route. 

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Computing the savings - during the voyage

During the voyage, the expected savings are presented to the user and are defined as: 

Expected savings = fuel on optimised route - fuel on reference route

By following precisely the Syroco recommendations, the user can expect to convert expected savings into actual savings. 

Computing the savings - after the voyage

After the voyage, as part of the reporting delivered to masters and fleet managers, Syroco Live computes the actual, potential and upside savings, defined as:

Actual savings = fuel on actual route (fuel actually consumed) - fuel on reference route

Potential savings = fuel on reanalysed route - fuel on reference route

Upside savings = potential savings - actual savings

While potential savings represent the maximum achievable savings in the actual circumstances, upside savings show how much more could have been achieved. 

Where it gets more complicated…

One must not forget that at the end of the day, savings aren’t everything. While they matter a lot, the primary responsibility of a vessel master is to keep the vessel safe and to respect commercial/contract constraints. This vessel evolves in a complex and fluid environment (no pun intended), and things rarely go exactly as planned. There are many factors that can cause fuel overconsumption: avoid local fishing activity or restricted areas, temporary power drop due to maintenance or engine issues, change of orders, port congestion, and many more. 

This is why, whenever we present savings numbers to customers, we must always be cautious about the upside savings. Theoretical numbers may or may not be achievable. Vessel masters understand this loud and clear, and so do fleet managers.