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Jotun 09/11/2016

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Ship design pushes green agenda

The Naval Architect: November 2016

The ratification of the Paris climate change agreement (COP21) by China and the US on 3 September will aid efforts  to reach the agreement’s target of a global temperature rise of less than 2oC, but other stakeholders, such as the shipping industry, must find a way to do more than their current share of sustainable work.

The aeronautical industry recently signed a landmark agreement on “a new global market-based measure (GMBM) to offset CO2 emissions from international flights and a comprehensive roadmap for the sustainable future of international aviation” at the 39th Assembly of the International Civil Aviation Organization (ICAO) on 6 October.  However, there is as yet no agreement between IMO member states on CO2 reduction targets despite new calls from the world’s national shipowner associations for the development of a GHG reduction timeline for shipping.

Instead, it is falling to initiatives such as Peace Boat’s Ecoship project, to push the green agenda forward and demonstrate what eco-centric designs can achieve if realised.

The Ecoship project was first discussed in 2014 as a response to the global cruise boom –particularly that seen in the Asian cruise market – involving the design and construction of an environmentally-friendly cruiseship that far outstrips the green credentials of the current best-in-class.

Its founding purpose was and is to challenge the cruise industry’s model in the wake of this rapid expansion of demand, demonstrating a ‘clean’ model by which the industry can move forward more sustainably. This new model utilises a host of green technologies to significantly reduce emissions and waste beyond current capabilities in a design that synthesises the technologies and moves the matter of sustainability to the heart of the way a cruiseship is designed and operated. 30 engineers, scientists and thinkers from fields such as shipbuilding to renewable energy, biophilia and waste management, developed the design of Ecoship.

Director of the Ecoship Project, Andrés Molina, stresses that “it is not a simple matter of advanced technology but, specially, a different and real environmentally friendly approach that is, in turn, an important part of the commercial presentation of the owner.”

The project is now at the stage of taking bids for construction of the vessel and is having design consultation carried out by DNV GL, a partner that recently signed a Memorandum of Understanding with Peace Boat at SMM in September, following original design work from Spanish firm Oliver Design. The contract for the build of the vessel is due to enter into force in 2017, with delivery scheduled for 2020.

Project goals
The main environmental goals include a 40% reduction of CO2 compared with Peace Boat’s current ship, Ocean Dream; zero SOx and NOx emissions; a 20% reduction in fuel consumption for propulsion (compared with cruiseships of a similar size); a 50% reduction in fuel consumption for the hotel (compared with cruiseships of a similar size); and use of LNG as a main fuel source for propulsion, while also using biodiesel, solar, and wind as much as possible to further reduce emissions.

Molina explains: “Compared with a ship built at the same time as the Ecoship, we might say that an approximate CO2 reduction of 20% will be seen, considering the sails, PV panels, special hull and other fuel saving measures as well as its operational efficiency approach.”

The intention is to deploy a diesel-electric system with two pods producing 10MW each and six dual fuel four stroke hybrid LNG/MGO engines that each produce 4.59MW. In addition, ten sails are to be fitted to the vessel in order to take advantage of Peace Boat’s long spells at sea while sailing around-the-world. This should reduce the propulsion power needed by around 10% in good wind conditions, says Molina. However, at this stage, the design of the sails is not firm and a range of options, from Flettner rotors to the foldable sails shown in the rendering of Ecoship, are being considered.

Andreas Ullrich, senior principal engineer international rules, DNV GL, and consultant to the project, explains that architects and the shipyard will need to discuss the best way of realising any sail design, taking issues of stability, and the impact of too much wind into account when making decisions. To this end, DNV GL’s current role in the project is to support Peace Boat in realising Ecoship’s complex design. This includes evaluating technical solutions and discussing the project with yards as well as suppliers. It will then act as class society during the construction of the vessel.

Wind power will also be used to generate electricity for the vessel. Approximately 150kW is anticipated to be produced in favourable conditions from wind generators positioned on Ecoship’s top deck. This alternative energy source will be contributed to by 10 wind generators, while 6,000m2 of photovoltaic (PV) panels (also positioned on the top deck and on cabin balcony fenders) will reduce the vessel’s hotel fuel consumption by about 750kW. Cabin balcony fenders will be fitted with PV panels to power cabin lighting, with batteries installed to store and retrieve energy overnight.

Energy storage and recycling are at the heart of the Ecoship project, and as such, a variety of storage solutions are being analysed for the vessel. These include hydrogen electrolytic plants, hot tanks for additional storage, frozen tanks to store ‘cool’, and electric batteries. There is also the suggestion of operating an energy balance system that would allow wasted thermal energy created at sea at service speed to be used while the vessel is alongside.

Peace Boat says the goal of the storage systems is “to store enough energy to stay alongside with either the engines stopped or running on H2 for six hours.” In this way, “Even a slight increase of the power of engines at sea should be better for the port ambient conditions than having engines running when alongside.”

Molina explains that 1,500kW (at 200oC) of wasted thermal energy, about 20% of the total, is available per day at sea at service speed to be stored and used when alongside. That is equal to 1,290,000 Kcal/h. Three days at sea has the potential to produce 17,200,000 Kcal if the efficiency of storage and extraction is improved, which means 3.5 hours of energy demand can be catered to while in port. In order to reach the goal of six hours of energy for the ship in port without engines, 500tonnes of frozen water and an additional 300kW from the ship’s engines while sailing for three days is necessary, as well as approximately 150tonnes of lithium batteries.

“Energy storage is one of the biggest challenges and H2 is a big temptation since it could be produced onboard using wasted heat, stored at 600 bars and burnt when the ship is alongside,” says Molina. “Theoretically, the new IGF covers LNG and other low flash point fuels, but H2 requires separated development…if we cannot get it for delivery, we will get it and install it afterwards.”
Heat from onboard cooling systems will be used to produce water that can be used for domestic applications, and, as a mark of the Ecoship project’s ambition, there is a target to reuse 80% of the energy normally lost in air and water.

Further recycling of resources can be seen in the water loops and waste loops portrayed in Figure 2 and Figure 3, as well as in the vessel’s innovative HVAC air loop system. This loop utilises onboard gardens as cooling towers. “Basically, desiccant units will dry and pre-cool the incoming air. That air is water sprayed and, so, cooled down to pre-cool the chiller water in the cooling towers (gardens with water evaporation). Then, the chiller water will go to the main chiller units. We may gain 3-4˚C in the chiller water. The desiccant units are re-generated with wasted heat,” Molina explains.

PMESC
A complex power management and energy saving control system (PMESC) is needed to combine the array of technological solutions to be deployed on Ecoship in an efficient holistic model.  “This is, in fact, one of the most crucial items for which the technology is not yet developed enough,” says Molina.
“For the time being we have only succeeded in the integration of the different distributed power management systems, but we did not get the proper upper level system to manage the power systems from a pure combined optimisation mode.”

The system will need to retrieve and analyse data from regular onboard power management systems such as propulsion and hotel loads, from external conditions (solar radiation, wind, waves, external temperature etc.), and internal ambient conditions like wasted energy re-use, wasted water re-use and energy storage levels. Peace Boat states it must be capable of optimising energy use and wasted energy recycling. However, self-consistent energy systems might be monitored and controlled by subsystems that work to alert the main PMESC if they do not require interaction with other systems.

“Nobody before realised the combination of wind, solar and ‘regular propulsion’ management including CO2 control and waste energy re-use,” says Molina. “The system would work as our own brain, where the unconscious (upper level management system) proposes actions and the conscious (Master) select and executes throughout the distributed energy management systems…plus the ‘learning’ adaptive function that is passing on the unconscious those functions that are becoming repetitive or that have been proven to be measurable through a mathematic algorithm. That requires research that only a few commercial makers are willing to do, so we are approaching universities. In any case, the ship might be delivered without the latest technology in place, but prepared to get it as soon as it is available.”

A route optimisation system will also be needed to balance the various propulsive technologies and power generation systems to make the most of wind and sea conditions.

Continuing development
It must be noted that Ecoship’s arrangement has been designed with flexibility in mind and so technological solutions, such as fuel cells, may be adopted and the GA changed to allow for this possibility and others in the coming months.

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