Study: Rotor Sails and Routing Can Cut Emissions By One Quarter

File image courtesy Norsepower

Published May 29, 2023 8:55 PM by The Maritime Executive

NAPA, Norsepower and Sumitomo Heavy Industries have released a study on the potential fuel savings achievable with a combination of rotor sails and weather routing on a primary trade lane. On the right route, the top-line number is a remarkable 28 percent, enough to make a notable difference in the bunker fuel bill. 

"Looking at the findings from this study, we think the CO2 emissions reduction figures exceed customers’ expectations," said Yuji Arai, Senior Engineer, Sumitomo Heavy Industries.

In the first phase of the simulation project, the partners examined six routes, including a North Atlantic passage between New York and Amsterdam, using a Sumitomo wind-assisted tanker design as the ship model. They drew on Norsepower's real-world data, as well as NAPA's digital-twin ship performance model. The simulation runs included voyages with and without the assistance of NAPA's routing software.

The combination of routing and rotor sails on the North Atlantic routes delivered a 28 percent efficiency improvement. About 12 percent came from routing, and the balance from operating rotor sails. 

Looking at results across all six routes - not just the transatlantic voyage - the study found an average CO2 reduction of 19 percent when using both routing software and rotor sails. The routing contributed about 10 percent of that total. 

Using results from the simulation, the study also explored how to predict vessel performance at the design stage, testing how the rotor sail-equipped ship could handle different sea and weather conditions.  
In the next phase, the partners will draw on real-world fleet data to search for strategies to improve the operational efficiency of ships fitted with rotor sails. 

The project is part of SHI's plan to develop a new proof of concept and strengthened business case for wind-assisted ships with Norsepower rotor sails. It will also help inform the shipowner's commercial and operational decisions in the design stage. 

“This joint simulation project shows the significant potential for combining wind propulsion with voyage optimization for planet-positive impact," said Pekka Pakkanen, EVP at NAPA. "Our findings are promising and can help bring much-needed clarity to help the industry meet its sustainability goals.”