Wind power: a storied past and sustainable future in maritime shipping

In December 2022, the Lloyd's Register Foundation remotely hosted three students from the University of Oxford for micro-internships. Over the five-day placements, they used HEC's digital collections to conduct a rapid literature review focusing on one of the Foundation’s big challenge areas - such as safety at sea and safety for a sustainable future. Aside from blogs, the micro-interns have produced social media posts from their research. In this blog, we learn more about Grant Sieboldt's research on fuel transitions.

Until the technological advances of the 19^th and 20^th centuries, wind power was the uncontested driving force for sea travel and shipping across the world. A familiar sight to all are the masts and sails of clippers like the Cutty Sark, designed for speed and efficiency; with little to no power other than the wind itself, such ships fuelled commerce, trade, and exploration, and dominated the seas for centuries. With the industrial revolution came new technology and innovation, and the rigs and sails of the past slowly saw competition, hybridization, and replacement by paddlewheels, propellers, and engines, and wind power faded out of mainstream shipping. But in another era of rapid change, where emissions from the shipping industry have become a global concern for human and environmental health and safety, wind is experiencing a resurgence of interest as a force for maritime power. After a few periods of brief experimentation in the 20^th century, it is emerging as a field of rich potential for powering ships, though its implementation is not without challenges.

With an eye toward the Lloyd’s Register Foundation’s Challenges, and particular concern for safety for a sustainable future, this literature review will focus on the history, development, and future of wind power in maritime shipping, and present sources which show the promises and concerns that accompany its re-adoption by the shipping industry.

A storied past

The history of ships is inextricable from the use of wind power. Before technological developments in the 20^th century, wind was the primary power source for shipping around the world. The advent of the industrial revolution and the development of the steam-powered vessel revolutionized the shipping industry, and made Britain an industry leader in shipbuilding.^[1] Wind power and sail-assisted technology were not left completely behind, however, and the technology had its fair share of interest and innovation in the 20^th century, when fuel costs rose to untenable levels and shipping emissions from fossil fuels became an environmental concern. Devices such as the Flettner rotor, invented in the 1920s, would spend decades waiting for widespread implementation, but were ready and waiting when interest arose.

The 1980s were a particularly fruitful period for wind propulsion (WP) and sail-assisted device implementation amid rising global fuel prices, and this is reflected by the bevy of 1980s literature on wind power found in the HEC archives. As the shipping industry sought viable alternatives to exorbitant fossil fuel costs, there was an international surge of interest in viable re-application of wind power. Japanese shipping vessels such as the Shin Aitoku Maru and Usuki Pioneer were outfitted with sail-assist technology and measured for fuel savings, to greater-than-expected effect.^{[2] [3]} There was likewise a revitalization of interest in the Flettner rotor, which utilizes the Magnus effect to generate lift and propel a ship forward if the wind is blowing in an optimal direction, and interest in this simple but effective technology led to widespread implementation and testing.^[4] The Royal Institution of Naval Architects held a symposium on all commercial and technological aspects of wind power in 1981.^[5] The British bulk carrier MV Ashington was outfitted with sail-assist technology known as the Walker wingsail in 1986, and when measured for performance, yielded similar stronger-than-expected results.^[6] Academic papers on other WP technology such as the Spins’l and kite sails may be found in the HEC archives from this time period.^{[7] [8]}

Similarly to its slow fade from prominence in the late nineteenth century, interest in wind power as a viable supplement or alternative to fossil fuels appears to have waned in the 1990s and early 2000s. As fuel prices fell and carbon emissions were not yet such a prominent issue, the HEC and outside literature reflects another temporary relative loss of interest in the technology. Its staying power would become clear in the coming decades, however, and make the relative lack of attention in the intervening period a valuable lesson for the industry. In hindsight, a more supported and sustained interest in a variety of technologies and possibilities such as wind power might have offered the industry a fuller picture of their viability and applications when needed most.

New interest, benefits and challenges

The literature inside and out of the HEC archives suggests that wind-powered shipping suffers not so much from a lack of viability or efficiency, as it does a lack of sustained research and persuasiveness to investors. A common thread of concern is the perceived retracing of steps; incorporating wind power on ships may feel to some like a backwards transition, and require extra training for a specialized workforce on procedures and safety of its use.^[9] Likewise, the upfront costs for wind power installation is high, and typically shows small yearly returns to an extent that might give investors pause. Carlo Raucci, Marine Decarbonisation Consultant at the Lloyd's Register Maritime Decarbonisation Hub, adds: "Investments are being channelled towards new fuels, and the stakeholders may want to see a package of solutions that also includes new fuels rather than investing solely in wind. With a rapidly changing landscape of regulatory framework, investors are looking for solutions that address decarbonisation rather than only fuel savings."

One historical issue with innovation has been the necessity for training specialized workforces in new technology, and the use of tech like Flettner rotors, which need to be operated and programmed in certain conditions, adds to the already significant investment and upfront cost of their installation.^[10] Several alternative fuel sources have drawbacks and potential for danger in the workforce, but not much public documentation appears to exist on safety procedures for wind power. Relatively simple, unobtrusive constructions such as windsails and Flettner rotors do not have problems like instability or upkeep to the extent that hydrogen or biofuels might cause, but will still require crew training and familiarity. Moreover, the technology may take up valuable space on cargo ships and carriers, reducing the efficiency of goods transport.^[11]

Another burden on wind power implementation is CAPEX; upfront costs of wind and sail-assist technology, which may have to be retrofitted onto existing ships, have made investors reluctant to purchase a technology which may offer relatively small savings in exchange.^[12] However, new benefits for emissions reductions and the comparative cost of not finding more sustainable approaches to ship power has made wind propulsion more appealing, especially in the last few years.^[13]

In all, wind power is an area of much promise for emissions reduction and fuel savings, which may outweigh initial investment costs and also add a health and safety element for passengers and crew –– the savings on emissions, driven by exciting new technology, promises a new era in hybrid and sustainable shipping. For these reasons and despite challenges, wind power has experienced keen renewed interest heading into the 2020s.

“The Decade of Wind”: a sustainable future

In 2021, the International Windship Association dubbed the 2020s as “the decade of wind” in light of a resurgence in interest, research, and implementation of various WP technologies. ^[14] In a world which is feeling the burden of carbon emissions, the savings offered by wind power for what appears to be a relatively small number of drawbacks has made the technology more appealing in the 21st century.

While this rapid literature review suggests that more research may be needed in safety procedures for wind installation, as well as an established standard for training and operation for the technology, the benefits of almost all types of wind power appear to be manifold. Carlo Raucci adds: "Future research would need to address the actual role of wind in the overall decarbonisation of shipping, for example investigating which subset of the global fleet suits most this solution and what is the best design when combined with alternative fuels like hydrogen and ammonia."

There is an ample body of research on fuel savings offered by Flettner rotors and the many types of sail-assist, and their implementation may offer sustained health benefits seen by reduction of Sox (Sulphur Oxides) and NOx (Nitrogen Oxides) for workers and crew.^[15] The Royal Institution of Naval Architects held a 2021 symposium which comprehensively covered the latest studies on technology, costs, retrofitting, viability, and economics of wind power^[16], and the International Windship Association is offering awards for standout sponsors of wind-assist technology.^[17] In all, the future looks bright for all varieties of wind-assist technology, and the renewed attention from the shipping industry makes it appear to be one of the most exciting areas of shipping innovation now. For the health and safety of workers and crew as well as for the environment itself, if interest in wind power remains sustained for the coming decade, it may write itself into the exciting and sustainable future of shipping, in a triumphant return from its storied past.

Disclaimer: The views and opinions expressed in this blog are those of the author and do not necessarily represent those of the Lloyd’s Register Group or Lloyd’s Register Foundation.

1. [1]Ships and steam power. Royal Museums Greenwich.[f/n] Sail and steam co-existed for much of the nineteenth century, but as shipbuilding innovations progressed further, the benefits of wind power were outweighed by the efficiency of other fuels.[fn]Ships and steam power. Royal Museums Greenwich.

1. [2]M. Murata, M. Tsuji & T. Watanabe. Aerodynamic characteristics of a 1600 dwt sail-assisted tanker (1981).

1. [3]“Substantial fuel savings for sail-equipped Usuki Pioneer”. MER (1985).

1. [4]A. Williams & H. Liljenberg. Revival of the Flettner Rotor. Beneficial or not for the merchant vessels fishing boats and recreational craft? (1983).

1. [5]Royal Institution of Naval Architects. Wind propulsion of commercial ships 4-6 November 1980: RINA Symposium (1981).

1. [6]P.M. Bonney & J. Walker. Wingsail operating experience on the MV Ashington (1986).

1. [7]T. F. Hanson. Sail Assist and the Spins’l (1986).

1. [8]A. Conway. Something’s in the wind (1985).

1. [9]Lloyd’s Register. Marine Technology Report: Driving New Technologies (2015).

1. [10]Seddiek, I. S. and Ammar, N. R. Harnessing wind energy on merchant ships: case study Flettner rotors onboard bulk carriers. Environmental Science and Pollution Research International 28, no. 25 (2021).

1. [11]Lloyd’s Register. Marine Technology Report: Driving New Technologies (2015).

1. [12]Hanson, E.K., Rasmussen, H. B., and Lützen, M. Making shipping more carbon-friendly? Exploring ship energy efficiency management plans in legislation and practice. Energy Research & Social Science 65 (2020).

1. [13]Zeldovich, Lina. High-Tech Sails Bring Wind Power to Big Ships. The American Society of Mechanical Engineers, February 10, 2020.

1. [14]McCellan, Amy. Back to the future with wind-propulsion. Institute of Marine Engineering, Science, & Technology, January 28, 2022.

1. [15]Lloyd’s Register. Understanding exhaust gas treatment services: Guidance for ship owners and operators (2012).

1. [16]Wind Propulsion 2021 Abstracts. The Royal Institution of Naval Architects (2021).

1. [17]Wind Propulsion Innovation Awards 2021. International Windship Association (2021).