Renewable Energy for Zero Emissions Shipping

The shipping industry today is actively looking at measures to reduce fossil fuel consumption and operate in a more environmentally friendly way. The concepts of "Green Shipping", "Green Logistics" and "Zero Emissions Shipping" are now important issues for ship owners, shipping companies and ship builders globally. In addition various regulations and initiatives are being implemented and these are aimed at reducing emissions & moving shipping towards lowering its environmental impact. Examples of these include Emission Control Areas (ECA's) and the limit on the sulphur content in marine fuels that came into effect in 2020. In addition the International Maritime Organization (IMO) has outlined an ambitious greenhouse gas (GHG) reduction strategy and the European Union (EU) has unveiled its own plan to reduce shipping related GHG emissions.

Now at sea, as well as on land, the use of renewable energy is increasingly being seen as part of the energy mix. Wind and solar power therefore will most likely play an important role in helping to reduce fossil fuel use and emissions across the shipping sector especially as renewable energy related technologies are further developed.

Past Use of Rigid Sails on Ships

In the 1980's several Japanese ships were fitted with rigid sails with the aim of reducing fuel consumption. This was largely driven by the oil crisis in the 1970's which resulted in oil shortages and prices soaring. During this time ships fitted with JAMDA (Japan Marine Machinery Development Association) sails including the Shin Aitoku Maru and Usuki Pioneer proved that these devices were an effective source of supplementary propulsion, with fuel consumption savings of approximately 10-30% being reported under favourable conditions.

These sails were not the primary source of propulsive power though. Even so, they were capable of moving these ships at low speeds without the use of the main engines. Therefore not only did the sails reduce fuel consumption but they could also be, under the right circumstances, a form of emergency propulsion. It was also reported that the sails at times improved vessel stability. However the crisis passed and when oil prices fell, the viability of rigid sails in terms of fuel cost savings was undermined.

Shin Aitoku with JAMDA rigid sails

 Shin Aitoku Maru fitted with JAMDA rigid sails (Source: Wikipedia)

Marine Solar Power

Recent advances in marine-grade solar cell and photovoltaic (PV) module technologies have led to solar power becoming a cost effective fuel reduction option on pleasure boats, ferries and tourist vessels. Even so, although PV modules may be designated “marine-grade” by the manufactures, those to be used for ship projects need to be evaluated carefully to avoid problems after installation.

Based on the PV modules currently available the amount of fuel that could be saved on a ship through the use of solar power alone is relatively small. Nonetheless there is scope to use solar power together with more energy efficient DC electrical devices to improve energy efficiency. But the idea of a commercially viable large ocean-going solar ship still seems impractical at the moment. Or is it?

Perhaps rather than having a ship with rigid sails or a ship with solar panels, a better approach would be to design a system that could tap into the power of the wind and sun together. The challenge in developing such a solution though is to overcome many of the practical problems entailed in trying to use sails and solar panels on large ships operating in the harsh marine environment.

This idea of combining the power of the wind and solar power is not new however, and in the 1990's a patent was granted in the United States for a solar powered electric ship concept that incorporated a traditional soft sail fitted with photovoltaic cells. Ideas and concepts that combine sails with solar power probably pre-date the 1990's though, however to date no combined wind power and solar power system that incorporates rigid sails has been deployed on-board a large vessel. But this situation is about to change.

Aquarius MRE® & EnergySail® - Wind & Solar Power for Ships

Aquarius MRE (Marine Renewable Energy) is a solution developed by Eco Marine Power (EMP) of Japan. It combines sail assisted propulsion (or wind assisted propulsion) with solar power and is essentially a ship renewable energy system. This patented wind and solar solution is designed so that the practical limitations of using rigid sails and solar panels on ships are overcome.

A ship fitted with Aquarius MRE such as a passenger ferry, cruise ship, bulk carrier, RoRo vessel or tanker will be able to tap into the limitless power of the wind and sun. These hybrid powered ships will use wind and solar power together as a source of energy and propulsion (along with the ship's main engines) in order to reduce harmful emissions and lower fuel consumption. On a large ship, 1000 tonnes or more of bunker fuel could be saved annually by using Aquarius MRE and CO2 emissions reduced by approximately 3000 tonnes. At the centre of Aquarius MRE is a patented rigid sail technology called the EnergySail. This innovative device can incorporate a number of renewable energy technologies and can be installed on a wide variety of vessels.

Impression of Aquarius MRE on Future Bulker Design Concept Impression of Aquarius MRE on Future Bulker Design Concept

A prototype of the EnergySail has completed land-based feasibility tests & a second factory produced EnergySail has been manufactured by Teramoto Iron Works in Onomichi, Japan. Teramoto Iron Works was one of the companies involved in the manufacture of JAMDA rigid sails in 1980's and this innovative company has a long history of manufacturing high quality products for the shipping industry. It is also one of the few companies in the world that has manufactured large rigid sails for ocean-going ships.

EnergySail Demonstration Unit at the Onomichi Marine Technology Test Center EnergySail Demonstration Unit at the Onomichi Marine Technology Test Center

The marine solar power sub-system within Aquarius MRE is known as Aquarius Marine Solar Power. Components of this sub-system were installed on-board the high speed ferry Blue Star Delos as part of a joint evaluation project with Blue Star Ferries. A second marine solar power system has been installed on-board the large general cargo ship MV Panamana and this system utilised for the first time class-approved UB-50 hybrid batteries from The Furukawa Battery Company.

Next Steps

In late 2017 EMP announced that it was working towards sea trials of Aquarius MRE. These trials will bring together the complete system on-board a ship for the first time. Additional lab and shore based testing will also be conducted during these trials and variations of the system developed. In addition EMP and its strategic partners are currently working towards obtaining Approval-in-Principle (AIP) for Aquarius MRE and investigating what other technologies could be integrated into the system architecture.

This article was written by Greg Atkinson, Chief Technology Officer, Eco Marine Power. ORCID 0003-2911-6317

It was first published on LinkedIn on January 8th, 2018. This version was updated on 27th August 2020.

Aquarius MRE, EnergySail and Aquarius Eco Ship are trademarks of Eco Marine Power Co. Ltd.


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Hybrid marine power solutions including solar power save fuel, reduce pollution and are cost effective. Eco Marine Power is at the forefront of developing low emission & fuel saving solutions for ships, Our computer systems also provide a control interface between renewable energy & other systems on-board ships.
Eco Marine Power is at the forefront of providing innovative marine renewable energy technologies for shipping that harness the power of the sun & wind. These solutions include Aquarius MRE, EnergySail & Aquarius Marine Solar Power. These reduce fuel consumption, lower noxious gas emissions and deliver cost benefits.
Aquarius Management & Automation System or Aquarius MAS is a cost effective alarm handling, monitoring & data logging platform suitable for a wide range of ships. The system is based upon the reliable KEI 3240 Data Logger and is class approved. Aquarius MAS can also monitor fuel use & calculate vessel emissions.
Our design & consulting services include green ship & eco ship concept designs, renewable energy surveys, renewable energy systems design & consulting support for new ship and retrofit projects. We work with ship owners, ship managers and ship yards to develop the right renewable energy solution for their needs.
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