^ Artistic Representation of the Ecoship – Image Courtesy of Peace Boat at http://ecoship-pb.com/ecoship/
Cruising Towards Greener Waters
Right from the Kyoto Protocol of the 1990s, climate change agreements have stopped short of bringing shipping and airlines within their purview. Why? Because ships and airplanes move through the territories of umpteen nations, each of which may have its own emission caps.
Not that this has escaped the sharp eyes of global institutions. At the Paris Climate Summit, the International Monetary Fund (IMF) for example proposed a carbon tax on the shipping industry, something the International Chamber of Shipping flatly rejected.
Whichever way you look at the UN Climate Change Summit at Paris in December 2015, it is historic. For, there is now a plan, conditional of course, to limit global temperature rise to less than 20C over pre-industrial levels.
At the summit, Japanese non-profit organization Peace Boat announced the final design of the Ecoship. When the Ecoship sails on its maiden voyage in 2020, it will be the greenest cruise ship in the world discharging 40% less carbon and zero sulphur and nitrogen oxides.
With the mission to create awareness and initiate action to inspire positive social and political change in the world, Peace Boat has undertaken regular voyages for peace, environmental sustainability, and human rights since 1983 aboard chartered cruise ships.
Ecoship’s design will be displayed at the World Future Energy Summit during the Abu Dhabi Sustainability Week to be held in January 2017. Here, Peace Boat intends to collaborate with players in the renewable energy field and draw inspiration from the Madsar City.
Madsar city is under construction in Abu Dhabi. It relies completely on solar and other renewable energy sources. Based on a holistic integration of business, education, and sustainable development, the city hosts the headquarters of the International Renewable Energy Agency (IRENA).
Peace Boat hopes the Ecoship will pioneer at sea what Madsar city did on land. Nominated for the Nobel Peace Prize in 2008, Peace Boat holds Special Consultative Status with the UN Economic and Social Council (UN ECOSOC) and makes recommendations to UN’s agenda.
The Need to Cut Shipping Emissions
Shipping is the most eco-friendly form of transport. It emits about 10 grams of carbon dioxide (CO2) to transport 1 ton of cargo over 1 kilometer. The corresponding figures for air transport, truck (tractor / trailer), and rail (diesel train) are respectively at 470, 59, and 21.
But that does not present the full, big picture. If shipping were a country, it would be the sixth largest carbon dioxide (CO2) emitter in the world. Back in 2007 itself, it spewed out as much as 3.3% of the globally emitted CO2.
Now, emissions from the cruise ship segment are not even the proverbial drop in the ocean. But, it is perhaps the most public face of the shipping sector. If the Ecoship ushers in greener changes, it will raise environmental awareness across global shipping to a whole new plane.
With the public pressure that such awareness will create, a green shift will eventually become inevitable. This is exactly what her makers hope for – to inspire cruise as well as passenger ships to adopt greener technologies.
Talking of the responsibility of cruise shipping, it does take tourists to some of the most ecologically pristine areas of the ocean. It therefore has a moral obligation to give something back to nature.
Ecoship: An Ecological Wonder
Providing a platform for research, education, and technology exhibitions for the green cause, the 55,000 ton vessel will provide proof of concept for eco-friendly cruise operations. Every year, Ecoship will carry 5,000 people and host exhibitions in 80 ports across the globe.
This is the first time that numerous specialists from multiple disciplines have closed ranks to design a cruise ship. Areas of consultation include environmental design, renewable energy, naval architecture, shipbuilding, biophilic design, and engineering.
Adopting an integrated approach in order to build a restorative vessel that delivers a net positive impact on the environment by combining the aforementioned areas, the vessel will establish a synergy between radical energy efficiency and closed material flow.
Elements of the system will complement instead of compensating for each other. Through all this, the Ecoship will emit 40% less carbon vis-à-vis the cruise ship emission standards of the pre-2000 era. Plus, it will discharge zero SOX and NOX.
Let us take a look at what makes the Ecoship special:
- The Ecoship draws inspiration from the humpback whale, fish skin, and natural ventilation:
- Aerodynamic upper hull is based on the features and contours of the humpback whale
- Non-toxic, anti-fouling hull coating mimics fish skin
- Natural ventilation
- Holding the distinction of being the world’s first 10-mast cruise liner, the Ecoship comes armed with withdraw-able wind generators, solar-powered sails, and hybrid engines
- The 6,000 square meter top deck solar farm and wind generators produce over 740 kW power and drastically slash the use of fuel, fuel that would otherwise burn and breathe out pollutants
- Even otherwise, the Ecoship uses the clean liquefied natural gas (LNG) as the top up fuel. LNG is the most eco-friendly fossil fuel of the day
LNG is a fuel cleaner than gasoline and gasoline is cleaner than diesel. Diesel emits 13% more CO2 than gasoline. Typically, LNG is 95% methane. The table below illustrates the relative merit of methane, ethanol, and gasoline:
Provided in the penultimate section of this article is an elaborate discussion on the relative merits and pitfalls of diesel and gasoline engines
- Its proactive, future-ready hybrid engine will burn bio-fuels and other clean energy sources as and when these become available in the near future
- Recycled waste heat from the ship’s main engines will assist heating and air conditioning. The vessel uses auxiliary turbo generators, exhaust gas boilers, and extra steam generators for this purpose
- Closed loop water system eliminates the need for discharging water at sea. The mechanism purifies and re-uses wastewater for irrigating the onboard garden. Rainwater and seawater also irrigate the garden
- The onboard garden with plants from around the world is, in the words of her makers, the heart and lungs of the ship
- Biophilic design of cabins. Such design is a relatively new concept related to green architecture that makes the environment an integral part of our homes, schools, offices, and hospitals
Biomimicry & Shipbuilding
Although man has always learned and copied from nature, this practice became serious in the business world only in the last two decades. It was only in 1997 that the term biomimicry was coined.
Humpback whales have a peculiar body shape consisting of a knobbly head and long pectoral fins. Across the leading edge of these fins or flippers are large and apparently irregular bumps or ridges called tubercles. Such tubercles also cover the head of the humpback whale.
It is these tubercles that bless the humpback whale with surprising acrobatic ability despite weighing a mammoth 36 tons and measuring up to 16 meters. This agility was a matter of immense curiosity for marine biologists and engineers alike. We may just have decoded the riddle.
Wind tunnel tests have demonstrated 32% lower drag, 8% lift improvement, and 40% rise in the angle of attack before stalling when using model humpback flippers with tubercles on the leading edge of windmill blades as compared to those without tubercles.
Like many other great innovations, this was the product of a coincidence. A leading expert in biomechanics and professor of Biology at Chester University, Frank Fish noted such tubercles on the leading edge of a small model humpback whale and assumed they were wrongfully placed.
Incorrectly because conventional aerodynamic theory requires leading edges of moving blades to be as straight and sharp as possible. Professor Fish experimented with similarly ridged blades for a windmill and noted a 20% hike in efficiency.
Apparently, these tubercles direct air to smaller areas of the blade and thereby provide higher wind speed through all the channels. This also creates a number of rotating airflows on top of the blade that supply additional lift.
Having codified the Tubercle Effect, Professor Fish worked with Phil Watts and obtained a patent for such leading-edge-ridged airfoils and hydrofoils. They then formed the company WhalePower and are looking to extend the efficiency hike to wind turbines, fans, and wings.
Not isolated from the Tubercle Effect is the Whale Tail project underway at the Norwegian University of Science & Technology (NTNU). It seeks to emulate the way whales use their tails and fins for propulsion – generating lift and slashing drag by using energy from advancing waves.
Model tests have demonstrated a staggering 9-17% reduction in water resistance at wave heights of under 3 meters, the average height of waves in the Norwegian Sea and the North Sea. Post doctoral fellow at the NTNU Department of Marine Technology, Eirik Bockman is testing the project.
Another related project is the Gator Sharkote at the University of Florida. Professor Anthony Brennan derived inspiration from sharks that remain free of fouling despite spending all their lives in water.
Fouling of the underwater part of the hull by algae, barnacles and other microbes escalates fuel use by as much as 40% by increasing the drag on and weight of the hull.
Microscopic rectangular scales topped with minute bristles and spines make shark skins uneven. Algae and barnacles cannot get traction on such a surface. Plus, these scales flex and move as the sharks swim and add to the troubles of the fouling organisms.
Professor Brennan developed a plastic-rubber coating of 15-micron, diamond-shaped patterns. Each pattern has seven ribs of diverse lengths. Passing electric current changes the profiles of these patterns. This becomes similar to shark skins and has given great trial results.
Diesel Vs Gasoline in Heavy Duty Applications
Since we have raised the issue of the relative pros and cons of fuels, let us further extend the discussion. If gasoline (petrol) is a more eco-friendly fuel than diesel, why don’t ships and other heavy duty applications use gasoline instead of diesel?
For one, diesel is less expensive than gasoline in most countries simply because you can refine diesel more easily from crude oil than you can refine gasoline. Second, diesel engines are more efficient than gasoline ones but this is an acutely intricate issue.
If we take two engines of the same size and set the same operational parameters, the petrol (gasoline) engine operating on the Otto cycle will be more efficient than the diesel one operating on the Diesel cycle.
Petrol engines are also called Spark Ignition (SI) engines because an electric spark ignites the gasoline. Whereas diesel engines are also referred to a Compression Ignition (CI) engines because compression and the resultant rise in temperature provides the ignition.
But we cannot employ a greater compression ratio in the gasoline engine because gasoline engines exhibit knock at higher compression ratios. The greater an engine’s compression ratio, the higher is its efficiency. Diesel does not undergo knocking hence the preference.
Compression Ratio is the ratio of the volume of the engine cylinder when the piston is at the bottom of its stroke to the volume when the piston is at the top of its stroke. Diesel engines typically employ a compression ratio of 14 to 22 while gasoline engines operate at 6 to10.
Made up of a long chain of hydrocarbons, gasoline ignites more readily than diesel. The latter consists of highly branched aromatics that delay its ignition. This physical property is the very crux of this discussion.
Knocking or detonation of gasoline occurs when gasoline does not ignite at the optimum point of time in the piston cycle. Engineers adjust the spark plug so that it provides the spark some time before the piston reaches the top dead center (TDC) i.e. top of the stroke.
Ignition timing is expressed in the number of degrees of rotation of the crank shaft before TDC (BTDC). For example, 12 degrees BTDC. Engines generate maximum output at maximum efficiency if the combustion gases are at their expansive best when the piston hits TDC.
Fuels do not burn completely the moment the spark fires. Nor do combustion gases expand immediately after spark. And the changes in speed of the engine change the duration in which the combustion and expansion occur.
It is for the want of this window of time that spark plugs are designed to fire before the piston hits TDC. Pre-Ignition or the ignition of gasoline before the spark plug fires usually precedes knocking. Knocking creates shock waves in the engine that can be catastrophic.
Employing greater compression ratios elevates the temperatures inside any engine and creates localized hot spots inside it. And because gasoline ignites more readily than diesel, it is more vulnerable to knocking inspired by such hot spots.
Moving over to fresh technologies and work practices is a process precarious at best, hazardous at worst. Although we love favorable changes, we are also haunted, consciously or subconsciously, by a fear of the unknown. And changes always bring with them the unknown element.
This is why innovations are slow to gain acceptance. But there comes a tipping point for every innovation when it crosses the threshold of popular credibility. From then on, nothing succeeds like success.
Carnival, the world’s largest cruise company, will order four LNG-powered ships from Meyer Werft between 2019 and 2022. These will be the world’s first LNG-propelled cruise ships.
As mentioned, LNG is the least polluting fossil fuel at present. Such LNG-powered cruise ships will demonstrate the efficacy of LNG propulsion in this cruise vessel segment and serve as role models for others to follow.
Welcome as this development may be, even these green cruise ships run the risk of falling behind ever-tightening emission regulations. And this is why the Ecoship can be exactly what the doctor may order in the future for the cruise ship industry in the not too distant future.
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