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NAPA, Norsepower and Sumitomo study finds average CO2 emissions reduction potential of up to 28% using rotor sails and voyage optimization

Joint simulation project among NAPA, Norsepower and Sumitomo analyzes the benefits of combining wind propulsion with voyage optimization to deliver maximum emissions reduction potential.

Helsinki, Finland, 30 May 2023; NAPA, a maritime software and data services expert, Norsepower, the global provider of auxiliary wind propulsion systems, and Sumitomo Heavy Industries Marine & Engineering Co., Ltd. (SHI-ME), one of the world’s leading shipyards, have today announced the results of phase one of their joint simulation project looking at the fuel saving and emissions reduction potential of combining Norsepower Rotor SailTM and NAPA Voyage Optimization onboard SHI-ME’s wind propulsion ship.

Phase one of the simulation project (from December 2022 to March 2023) found that the combination of NAPA Voyage Optimization with the Norsepower Rotor SailTM can deliver emissions reductions of 28%, on average, on the Atlantic route between New York and Amsterdam. Of these average CO2 emissions savings, the contribution of NAPA Voyage Optimization can be estimated at 12%.

The joint simulation project leveraged insights from NAPA’s ship performance model and its voyage simulation tools, as well as Norsepower’s actual performance data. Using nowcast weather data from 2022 and specifications provided by Norsepower and SHI-ME, the digital twins developed by NAPA were able to simulate the performance of the tankers in selected sea areas. Focusing on the annual voyages of six popular trading routes, the study evaluated the tankers’ estimated CO2 reduction and potential fuel saving with NAPA Voyage Optimization and Norsepower Rotor SailsTM, and compared these with using only NAPA Voyage Optimization. Looking at results across all six routes, the study found an average CO2 reduction of 19% when using NAPA Voyage Optimization alongside Norsepower Rotor SailsTM, with NAPA Voyage Optimization contributing 10% of these emissions reductions. Using insights from the simulation, the study also explored how to predict vessel performance at the design stage, testing how the ship could handle varying sea and weather conditions.

Phase two of the research project (May 2023 onwards) is designed to build on phase one and enhance the performance of vessels with Norsepower Rotor SailsTM. Using fleet data, the study will conduct advanced performance analysis to improve operational performance and explore new optimization strategies. The project is part of SHI-ME’s plan to develop a new proof of concept for wind-assisted ships, which will be equipped with Norsepower Rotor SailsTM.

The project and its findings will help strengthen the business case for investing in wind-assist technology at a time when the industry is under increasing pressure to decarbonize. Using NAPA’s operational voyage simulation technology alongside the technical expertise of Norsepower and SHI-ME, the collaborative study brings critical insight and assurance to inform commercial and operational decisions as early as the design stage.

Pekka Pakkanen, Executive Vice President, NAPA Shipping Solutions, said: “This joint simulation project shows the significant potential for combining wind propulsion with voyage optimization for planet-positive impact. At a time when the industry is racing to comply with environmental regulations, digital solutions are enabling greater collaboration with stakeholders across the maritime value chain. This joint simulation project was no different. Our findings are promising and can help bring much-needed clarity to help the industry meet its sustainability goals.”

Jukka Kuuskoski, CSO, Norsepower, added: “Norsepower’s mission is to lead shipping towards zero carbon emissions, so it has been an honor to work alongside top experts such as NAPA and SHI-ME. At a time of growing international regulatory and public pressure to save fuel and reduce the industry’s environmental impact, this performance data on the benefits of adopting clean technologies will give the industry the necessary confidence to invest in decarbonization. We are proud of this project and its future impact.”

Yuji Arai, Senior Engineer, Sumitomo Heavy Industries Marine & Engineering Co., Ltd. (SHI-ME), said: “SHI-ME’s vision is to deliver innovative and state-of-the-art vessels for shipping’s decarbonization. The Norsepower Rotor SailTM, NAPA’s knowledge of weather routing and SHI-ME’s expertise in tall-ship design are all vital pieces to materialize the vision of a greener industry. Looking at the findings from this study, we think the CO2 emissions reduction figures exceed customers’ expectations.”

Fuel-savings maximized with NAPA Voyage Optimization

Image 1: Graphic highlighting some of the route options available to maximize fuel savings. Voyages sailed using NAPA Voyage Optimization achieved the biggest fuel-saving results by sailing north of the UK.

Wind chart demonstrating savings when combining rotor sails with NAPA Voyage Optimization.

Image 2: Wind chart comparing all 24 voyages from New York to Amsterdam throughout the year. The project found that there were greater savings gained from combining rotor sails with NAPA Voyage Optimization and more favorable side wind conditions.

Notes to editors

About NAPA
With over 30 years of operation, NAPA is a leading software and data services provider for ship design and operations to enable safer, more sustainable, and future-proof maritime industry. Headquartered in Finland, NAPA employs 200 experts, combining expertise in naval architecture, fleet operations and digital services. NAPA operates globally, with a presence in Japan, Korea, China, Singapore, the USA, Germany, Greece, Romania and India.

With over 90% of new vessels built by NAPA customers, NAPA’s ship design software is the global de facto standard in shipbuilding. Furthermore, NAPA is a market leader in ship stability management and safety data services for passenger ships, and its cloud-based solutions for ship performance monitoring and voyage optimization support shipping’s decarbonization journey.

About Norsepower
Norsepower Oy Ltd is a Finnish clean technology and engineering company pioneering modern auxiliary wind propulsion for the global maritime industry. The Norsepower Rotor SailTM has been used by customers for over eight years and has been proven as a low-maintenance, easy to use, and reliable fuel saving technology, which is supporting the decarbonisation of the shipping industry.

Since its establishment in 2012, Norsepower has raised more than €40 million of funding and has now installed Norsepower Rotor SailsTM onboard eight vessels, including the latest installation on CLdN’s MV Delphine and upcoming installations on Alcyone, M/V Koryu, a MOL in-service Capesize Bulk Carrier and two LNG-powered, wind-assisted newbuilt CO₂ carriers for Northern Lights JV. Each installation has made significant reductions to fuel costs and emissions, confirmed by independent third-party verifiers such as ABB, NAPA, and Lloyd’s Register. Other shipowners, charterers, and shipyards have been convinced of the Norsepower Rotor SailTM benefits. They are taking steps, such as fleet-wide negotiations, to harness the technical and economic feasibility of Norsepower Rotor Sail™.

For more information on the Norsepower Rotor SailTM, please visit

About Sumitomo Heavy Industries Marine&Engineering Co., Ltd. (SHI-ME)
Sumitomo Heavy Industries Marine&Engineering Co., Ltd. is a subsidiary company of Sumitomo Heavy Industries, Ltd. and originated from Uraga Dock Co., Ltd., founded in 1897. Over 1,400 vessels have been built by Uraga Dock and then SHI-ME in about 120 years, including three modern tall-ships, i.e., Nippon Maru (1984), Kaiwo Maru (1989) and Akogare (1993).

For more information, please visit

Press contact
Rohini Lakhani
BLUE Communications

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