Shipping has been serving humanity since its inception. The history of maritime trade is thousands of years old, evidence exemplifying the existence of shipping among civilizations at least from two millennia. The earliest known sailing ship can be dated back to 3100 BC, when Egyptians utilized the north wind to travel south on the Nile. It is believed that true ocean-going vessels were developed by the Austronesia people which thereafter formed the basis of trade into South Asia and the Arabian Sea by around 1000 to 600 BC.

Indian rich heritage and culture also illustrate the prominence of shipping and sailing dating back to 2000-3000 years. Images of sea-faring vessels are few and far between as in Bharhut Stupa, Ajanta Caves, and Goa’s hero memorial stones. It is truly said that the Indian history of maritime prowess can be traced through the sculptures across the country.  The only cave sculpture of a boat is at the Kanheri Caves in Mumbai, dating back to the 2nd Century AD represents a shipwreck with two men praying to the god Padmapani, the first-ever indication of the maritime voyage through sculptures.

Maritime history widespread across centuries and millennia didn’t witness as drastic as a change we have witnessed in the last century in terms of propulsion. We have has witnessed a rapid transition from renewable power of a sail to the coal power of steamships and the current dominance of heavy fuel oil, marine diesel oil with a steadily rising influence of LNG, Electrical propulsion, and other alternatives onto the propelling power in maritime.

The International Maritime Organisation (IMO) has called for a reduction in GHG emissions by at least 40% by 2030, pursuing efforts towards 70% by 2050, compared to 2008); and that total annual GHG emissions from international shipping to be reduced by at least 50% by 2050 compared to 2008. To meet this ambitious goal of sustainable shipping future, the industry needs energy-efficient designs which have verily built an innovative and collaborative ecosystem among IMO Member Nations, Research and Development Organisations, and shipping companies to explore various alternatives for propulsion.

When we talk of renewable energy in shipping, we look forward to the primary, hybrid, or auxiliary propulsion as well as on-board and shore power usage. Renewable energy surely comes with an opportunity to transform the global fleet at all levels and scales including coastal and inland transportation, fishing, tourism, etc. Speaking broadly, renewable energy offers these potential solutions for shipping:

• Wind Energy- soft sails, fixed wings, rotors, kites, and conventional wind turbines.
• Solar Photovoltaics
• Biofuels
• Wave energy, assisted with the supercapacitors.

Wind Energy: the Ancient Technology with Modern Tincture

With many industry drivers and stakeholders supporting the technology, wind-based propulsion systems are being seen as one of the major clean alternatives with a viable future across many maritime sectors. This ancient concept can work in two ways in the modern scenario- either by maintaining the same ship speed for reduced engine power, fuel consumption, and resulting emissions, or by increasing ship speed for the same engine power for shorter voyages and increased ship profitability. As per Lloyd’s Register, around 10% of the global fleet- nearly 6000 ships are compatible to be retrofitted with ‘wind-assisted propulsion’ systems. However, International Windship Association believes the number to be much bigger.

The various prototypes assert the fact that the fuel-saving that could be tapped with ‘wind-assisted propulsion’ ranges between 10%-80%. The retrofits could give 10%-30% of fuel savings. Wind propulsion for cargo ships has been a matter of research for some time. B9 Cargo sail ship, a prototype by Ireland Based B-9 Shipping has designed 100% fossil fuel-free ship. B9 houses a unique propulsion system that uses wind energy for 61% of the power needed for propulsion and the rest is achieved by biogas-powered ancillary engines.

Skysails/ Kite-based technology is being installed on ships for a decade and a half that utilizes towing kites to assist propulsion and reduce propulsion. MS Beluga SkySails- a 172 m ship with a capacity of carrying 474 TEU was fitted with 160 m^2 sails (expandable up to 320 m^2) and completed her maiden voyage in 2008. It was observed that the technology could save up to 2.5 tonnes of fuel per day. The pilot testing concluded that fuel savings between 10%-35% could be achieved by 600m^2 sails.

1994 built dry cargo bulk carrier Aghia Marina was retrofitted with the world’s largest kite of 320m^2 as auxiliary wind propulsion produced by SkySails in the first quarter of 2012. The retrofit generated a propulsion power of more than 2,000 kW (approx. 2,700 HP) to cut down consumption of the bunker fuel and as well as SOx, NOx and CO2 emissions by up to 35 percent in ideal sailing conditions; which is again environment friendly and boasted Aghia Marina as a Green Ship.

When we talk of going back to sails or wind-assisted propulsion, we can’t afford to ignore ‘Flettner Rotors’. Flettner Rotors are a supportive propulsion system working on the Magnus effect possible retrofitted primarily for the ships and trades that benefit most from wind-assisted propulsion Enecron which deals in wind energy generation and technology commissioned the E-Ship-1 in 2008 that acts as an equipment and turbine transport vessel. According to the official statement from the company, Flettner rotors helped reduce fuel consumption by 25% compared to conventional systems. Maersk Pelican, the world’s first tanker to be retrofitted with ‘wind-assisted propulsion’ technology- Flettner Rotors by Norsepower in 2018. The trial of over one and a half years demonstrated a fuel savings of 8.2%. The ship was sailing on routes in Far East Asia, which was far from optimal when it comes to wind conditions, and afterward more on transocean voyages which helped boost the numbers later on. During this time, the technology was used 50% of the time in line with weather conditions. However, a ship like Maersk Pelican sailing on a different route, like a North-Atlantic crossing from Rotterdam to New York, for example, would have the potential to achieve up to a 20% cut in fuel consumption, Norsepower believes. A capable of saving up to 3% to 15% on main engine fuel consumption depending on vessel size, segment, operation profile, and trading areas. However, some believe that it can fetch a fuel-saving as high as 35%.

Likewise, Anemoi has developed rotor sails technology with rail deployment system to minimise disturbances in any type of port operations (bunkering, cargo load or discharge etc.) for bulk carriers and similar vessels. The technology promises 5-30% fuel and emission savings offering rotor sails in various sizes as per the vessel dimensions and specifications. However, the cost of implementation of flettner rotors is too high to get a nod from investors and financial stakeholders. (ranging from $1,000,000 to $3,000,000 for a typical delivery with multiple rotor sails, as per GloMEEP IMO).

The Wallenius Marine’s Oceanbird is one of the most talked of projects in wind propulsion technology. The project could reduce the emissions by 90% says Wallenius. The project by Wallenius Marine, KTH Royal Institute of Technology and SSPA and supported by the Swedish Transport Administration is under development phase from 2019-2022. It is expected that the first vessel out of the Oceanbird Concept would sail in 2025. An Oceanbird vessel would incorporate five steel and composite materials built rigid sails of 80 meters which could reduce to 20 meters height giving additional advantages of passing under bridges, adaptability, and easier maintenance. These sails give the vessel enough power to carry 7000 cars.

The diverse options in wind energy based propulsion systems have evidently showcased their profitability through pilot projects, prototypes and testing models. Except convential wind turbines, all other probable options coming through wind energy- soft sails, hard sails, flettner rotors, kite sail etc. have demonstrated their applicability on a larger scale.

Talking about the overall contribution of renewable energy technologies to international shipping, it is unlikely to master any major dominance. However, it has strong and increasingly proven capacity to make a modest contribution in many sectors over the short- and medium-term. For selected applications, the role of renewables can be significant, even dominant.

Overall, the most significant potential is using a combination of Renewable Energy Options for shipping that increases the availability and compatibility of energy sources in hybrid systems. In addition, hybrid models can promote better commercial performance. In this respect, achieving the maximum potential of renewable energy in the shipping sector will require an engineering approach to systems that integrate and resolve barriers to their use. Obstacles in the way of adoption of renewable energy in the shipping sector are complex. These can be categorized under organization/structure, character, markets, and non-market items. This complexity, in part, reflects the unique and international nature of the shipping industry, with fewer barriers and factors beyond individual capacity to make incentives and policy and regulatory framework needed to overcome the obstacles. In terms of organizational, organizational, and ethical barriers, limited funding for R&D, especially in early graphics technology, is a significant factor, and shipowners' concerns about the risks of hidden and additional costs and the potential for renewable energy solutions. This is especially true as, historically, there has been a lack of reliable data on the price and possible savings of specific operational measures or renewable energy solutions for the sector.

About market constraints, the main problem is that incentives separated between shipowners and tenants reduce the incentive for owners to invest in clean energy solutions for their shipping stock because profits do not always remain in the investment group. Therefore savings cannot be fully repaid. Another obstacle is the risk of investment in the sector, especially following the 2006 shipwreck. In addition, the shipping sector is not visible to the general public, leading to less social pressure in the industry to convert clean energy solutions. Of these non-market barriers, various categories and shipping scales, markets and trade routes provided, and the lack of capital availability are vital obstacles that need to be addressed.

About other 

Amit Kumar, an ex Merchant Mariner is founder and CEO of Sea and Coast Maritime Magazine.