GUTTA-VISIR is a service for operationally providing least-CO2 ferry routes. It combines numerical meteo- oceanographic forecasts with both the ship route optimisation model VISIR and a dedicated environment for operational production. The regions of interest are the Adriatic and Northern Ionian Seas. The optimal routes are computed at the CMCC high-performance computing facility by means of the VISIR model and then made available through a dedicated web application (www.gutta-visir.eu). Both the CO2 and the Carbon Intensity Indicator (CII) savings resulting from route optimisation are provided to the end users. GUTTA-VISIR has been in continuous operation since November 2021 and 39,600 among the routes published since were statistically assessed. It is found that the maximum CO2 savings for a given route are related to the average sea state, that the CO2 savings on any given route are nearly exponentially distributed, and that the largest mean savings are obtained for routes in the southern part of the basin. While the average savings for these short-sea routes in a relatively calm basin are around one percent, two-digit savings relative CO2 emissions can be obtained on specific dates and routes. Furthermore, it is seen that the route optimisation process can account for about one tenth of the CII reductions required in 2023 by the International Maritime Organization. These results provide a first objective assessment of the potential of ship routing for decarbonisation of short-sea shipping.

in "Scaling Decarbonisation Solutions: Reducing Emissions by 2030" by the Royal Institution of Naval Architects, 2022 ISBN No: 978-1-911649-37-3 ISSN No: 2752-6569