The answer is blowin’ in the wind


Gavin Allwright, Secretary-General of the International Windship Association, takes stock of promising developments in wind-powered shipping

Shipping has always navigated its own unique route. It was the first truly globalised industry, and the ships that sailed the oceans through the ages forged the world we know today, for better or worse, through trade, migration and the projection of military power.

For millennia the world fleet was powered almost exclusively by the potent power of wind (with a sprinkling of muscle power) and wind only finally relinquished that crown in the early 20th century. Fast forward 100 years and we find that the use of direct wind propulsion is experiencing quite a renaissance. An abundant, free, zero-emissions energy source, it is being recognised and rediscovered by many industries; but it is clear that with the use of modern materials, a high level of automation, and integration with other forms of propulsion, things have moved on significantly.

Looking forward

One of the larger ships using wind power: the Greek operated 64,000 dwt Ultramax bulk carrier Afros, fitted with Flettner rotors from the British company Anemoi. Afros was named ship of the year by Lloyd’s List in 2018. Photo: IWSA

As an industry we are now faced with our third major energy transition. The transition from sail to coal took over a century. Coal to oil took half that time. But if we are to avoid the worst ravages of climate change the transition to Shipping 4.0 must be effectively completed within the next two decades. To achieve this transition in an orderly and affordable manner, wind has to be incorporated at the heart of decarbonisation efforts. The future of shipping propulsion is hybrid.

The development of wind-assisted and primary wind propulsion solutions has been gaining significant momentum since the release of the IMO GHG initial strategy in April 2018. While wind has not yet become a mainstream energy option, we are seeing the involvement of many mainstream shipping and non-shipping stakeholders, ranging from MOL to Cargill, Louis Dreyfus Armateurs, K-Line, Oldendorff, Scandlines, Wallenius Willemson, Vale and other shipowners, along with such major shipbuilders as Chantiers de l’Atlantique, DCIS and Oshima Shipyards, as well as all of the major classification societies. Non-shipping players are also increasingly engaging with wind propulsion projects and technology providers. These include the Renault group, the European Space Agency, Drax, Hennessy and Michelin, to name just a few. The International Windship Association (IWSA) itself has grown over the past seven years, from 12 founding members to over 130 active members from across the industry.

Wind propulsion solutions (sails, rotors, kites and so on) offer a near-term opportunity for significant reductions in fuel consumption and associated emissions. As a retrofit option, with no change in vessel operational profiles, they can deliver 5–20 per cent savings, and have the potential to reach 30 per cent as the systems’ increased size, improved design and operational changes are factored in. Systems integrated into optimised new builds and used for primary propulsion will naturally offer substantially higher savings. Support technologies such as sophisticated weather routeing systems, satellite forecasting and even LiDAR are also being developed to fully utilise the wind energy available at any given time on any given route.

In the face of increased pressure to limit power on vessels or reduce their speed, wind also provides the ability to maintain speed along with a reduction in the amount of expensive alternative fuels consumed and the increased storage space they require. Range can be extended, and currently uneconomical trading routes could be revitalised.

The present

Ankie – another Dutch cargo vessel retrofitted with ventifoils from Econowind, also a Dutch company. Photo: IWSA

A variety of wind propulsion technologies are increasingly available today, with a growing number of demonstrator vessels already in commercial operation, sea trialling or in late-stage R&D. These systems are fully automated and will be integrated into the energy management systems of the vessels. There are seven main categories of wind propulsion technology: rotors, hard or rigid sails, suction wings, kites, soft sails, turbines and hull form. There are substantial technical variations within these categories, with over 30 technology providers and developers currently operating across the categories. Each system has its particular strengths, and is best suited to particular vessel types and sizes.

At the time of writing, there are in operation 16 large commercial ocean-going vessels with wind-assist systems that augment the main propulsion system. These range from large tankers (VLCC) and large bulk carriers (VLOC) through to roll-on/roll-off (RoRo) vessels, ferries, cruise vessels, general cargo ships and fishing vessels. This number is supplemented by over 20 sail-driven small cargo and traditionally-rigged cruise vessels. The large vessels use a variety of mechanical sail types. These include Flettner rotors or rotor sails with electric motor rotated cylinders developed initially in the 1920s, which use the Magnus effect of pressure differentials to generate thrust; various rigid sails or foils more familiar to racing enthusiasts (many of these are in late stage R&D); and suction wings  –  stubby aerated wing sails with an internal suction device to draw in the boundary layer for additional thrust, developed by a team for Jacques Cousteau’s Alcyone research vessel in the 1980s. Kites are also returning after a brief period of initial deployment while oil prices were high a decade ago, along with developments in turbines and hull forms that harness the wind. All of these systems have incorporated the need to stow, move or furl the rigs for operations in port, and to accommodate air draught considerations or extreme weather conditions.

Back to the future

‘Neoliner’, a French project – a primary wind RoRo ship, projected to enter service in 2024. Photo: Mauric

Where is wind propulsion going? To answer that question, we should take a look at third-party projections. A report published by the EU in 2016, well before the adoption of the IMO GHG initial strategy in April 2018, stated that, should some wind propulsion technologies for ships reach marketability in 2020 then the market potential for their installation in bulk carriers, tankers and container vessels was estimated to be up to 10,700 installed systems by 2030. We are currently on track: there is roughly a doubling of installations each year, with 2021 likely to end with installations on a total of 20 ships, equalling over 30 installed rigs. There is also the trend developing for larger or multiple rigs, and the pipeline indicates that this trend will continue, doubling again by early 2023.

Another important market projection can be found in the UK Government’s Clean Maritime Plan (July 2019), which assessed the global market for wind propulsion systems and estimated it to grow from a (conservative) £300 million per year in the 2020s to around £2 billion per year by the 2050s: approximately a quarter of the size of the market for alternative fuels. The research backing those forecasts expected to see wind propulsion installed on 37,000–40,000 vessels by the 2050s – roughly 40–45 per cent of the global fleet.

With all of this potential comes the need to create a level playing field in regulatory, economic and financial approaches. Work is under way on a number of projects to improve that situation. We have the EU-backed Wind Assisted Ship Propulsion (WASP) project, which features five retrofitted rig installations on existing vessels, and is working on testing, validation and business case development around these systems. The separate WiSP joint industry project is working on standard prediction models, and regulatory issues such as improvements to EEDI/EEXI (energy efficiency indexes respectively for newbuilds and existing vessels), while IWSA itself is initiating an international multi-stakeholder working group on wind propulsion to tackle the outstanding issues. The association also has a wind propulsion accelerator program under development that will assist R&D and wind system optimisation, using a test fleet and support programs. All of these initiatives are helping to create a more ‘primary renewable friendly’ environment in the industry.

While there are still market and non-market barriers to overcome, the zero-emissions energy from wind is there to be harvested and directly applied to propulsion, not only as a secondary source of renewable energy after the production of fuels. The price of fuel is on the rise, with carbon pricing on the horizon and expensive alternatives coming onto the market. The wind propulsion technologies coming to market are sound, viable and fully certified. As they are adopted on more and more vessels over the next couple of years, costs will start to come down. Wind has the potential to turn a supposedly ‘hard-to-abate’ sector into a decarbonisation pioneer. The choice we face is simply ‘blowin’ in the wind’!

Gavin Allwright, Secretary-General of the International Windship Association (IWSA), sits on the IMO’s MTCC advisory committee, is a non-executive board member for the World Wind Energy Association (WWEA) and is a leading participant in the EU Wind Assisted Ship Propulsion project. He has a master’s degree in Sustainable Development, and is a guest lecturer at the World Maritime University. IWSA is a not-for-profit organisation promoting wind propulsion in commercial shipping.

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