Norwegian operator Solstad Offshore says that one of its largest construction vessels, ‘Normand Vision’, managed to save significant amounts of fuel and reduce emission on a voyage home from a project in West Africa.
Through cooperation with long-term client Ocean Installer, good planning and pro-active crew and onshore management the ship managed to save 150t of fuel on this transit alone, saving about NOK 1.5m and 480t of CO2 emissions.
By taking weather and sea conditions into consideration, the team were able to find an optimal average speed of 9.7 knots for the 5000 naut mile route, with the speed being as low as 8 knots at some parts of the transit. An estimated saving of 25% was obtained compared to what was originally planned and what is industry standard for this kind of operation.
Solstad introduced ‘Solstad Green Operations’ back in 2010, focusing on simple operational measures that the crew, often in close cooperation with the client, can do on a daily basis to reduce emissions. For 2023 Solstad is focusing on the use of slow steaming whenever possible, specially on long transits to and from West-Africa, America and Asia/Australia.
The most efficient speed for offshore vessels is normally well below 10-12 knots. By combining the optimal hull speed with running the least number of generators, the lowest consumption in litre/naut mile can be found.
Tor Inge Dale, Chief Sustainability Officer said: “Sometimes we can experience some challenges in combining projects and operations with slow steaming but surprisingly often we see that this can be done without significant deviation in the operational plans and, at the same time, give considerable emission savings.”