The lion’s share of attention in our quest to neutralize carbon emission in the transport industry has always been on road transport. It’s the technology we all interact with every day. It’s visceral. The smell, sound, and size of the internal combustion engines near inescapable but if we actually examine the world’s carbon emission we start to see some less obvious polluters that don’t get much attention. Yes we are talking about road transport it accounts for around 12% of our total greenhouse gas emission, and we have the technology. to reduce that to zero. But what about 88%? There are many industries around the world working to neutralizing their carbon footprint and each of them is coming with genius technologies to get them closer to that target. One of the industries is the shipping industry is responsible for 2% of the whole world’s emissions, the vast majority of which is created by container ships, which carry 80%of the world’s trade.
There aren’t millions of cargo ships hauling our commodities around the world. Maersk the world’s largest shipping company with 17.6% of the world’s market share of container transport only has 786 gigantic ships these ships typically last 20-30 years, so it is important that we prepared to convert these ships to carbon-neutral technology when their time comes. The largest ship of this company “The Triple E” is the same length as the empire state building the scale of the ships is mind-blowing. A single triple E is capable of hauling over 20 thousand TEU, which just means it can carry 20,568 standard 20ft container. To put that into more human terms, a single 20ft container can contain 6000 shoe boxes. So a single triple E ship could deliver 12,34,08,000 pairs of shoes. It’s easy to see these ships as gigantic pollution machines. Each one of these ships has an astonishing impact on global emissions. Maersk as alone released over 36.5 million metric tonnes of carbon dioxide in 2019. Roughly equal to a small country’s emissions. But as a matter of fact, cargo ships are much more efficient than any other means of transport. This figure was closer. To 6 gm in 2007. But Maersk didn’t invent some revolution to achieve these they just slow down the fuel consumption of these ships primarily a function of the size, weight, and speed. The practice of lowering speeds began in 2007, not because of climate change concerns, but as a result of rising fuel prices. Today, as climate change has come into focus a 42% reduction in emission, is great but. getting to 60% by 2030 and 100% by 2050 as Maersk aims to do won’t be easy. Slowing down the ship to reduce fuel consumption is a game of diminishing returns, below 12-15 knots and it doesn’t make sense, and to achieve 100% with this method we just need to turn off our engines, a good way to collapse the world economy so what’s the plan to get to 100%?
THE RISE OF RENEWABLE SHIPPING
In the early 20th century, scientists proposed using the Magnus effect to propel ships. German engineer Anton Flettner replaced 420 square meters of sailcloth on the schooner Buckau with two 15-meter-tall steel rotor sails, which were set spinning using a small engine. Flettner showed that wind traveling around the Buckau’s rotor sails created a force on the sides of the rotor sails that propelled the ship forward. In 1926, the Buckau crossed the Atlantic Ocean. However, Flettner failed to find investors interested in rotor sail-powered ships. Fuel prices were simply too low and there were no environmental regulations limiting ship emissions.
But the economic breeze may be freshening for sail power. Today, more than 90% of goods are carried over the ocean, and the Chinese port of Shanghai alone saw 36 million containers pass through in 2015. All that commerce comes at an environmental price: Most vessels burn heavy fuel oil, producing heat-trapping carbon dioxide as well as soot and sulfur compounds that contribute to acid rain. Norsepower has developed a rotor sail based on Flettner’s original design but updated with modern materials such as carbon and glass fibers that cut its weight by a factor of three. That means less electricity is required to spin the rotor, which translates into more efficient propulsion. “Our largest rotor sails can provide forward thrust equivalent of up to 3 megawatts of main-engine power while drawing less than 90 kilowatts of electricity. Norsepower’s design is also linked to software that adjusts a rotor’s rate of rotation—up to several hundred revolutions per minute—to maximize forward thrust. “It’s fully automatic and simple to use. The technology also should be safe, as cutting electricity to the rotor stops the propulsion and leaves only a drag force. And that drag force is probably much less significant than the drag the ship’s hull experiences moving through water. Rotor sails are generally effective if the wind is moving faster than 18 kilometers per hour—roughly 10 knots—and is blowing across the ship’s bow at an angle of at least 20°. Ships often encounter such conditions on northern Pacific and northern Atlantic shipping routes. Unlike Flettner’s original rotor sails, the new versions are intended to only provide supplemental thrust rather than entirely replace a ship’s engine.
Norsepower, together with project partners Maersk Tankers, Energy Technologies Institute (ETI), and Shell International Trading and Shipping Company, today announced the trial results of two Norsepower Rotor Sails onboard the Maersk Tankers product tanker as interest in wind power for the merchant fleet hits new highs.
The rotor sails are large, cylindrical mechanical sails that spin to create a pressure differential, the Magnus Effect, that propels the vessel forward; in this instance a Maersk Tankers’ Long Range 2 (LR2) product tanker vessel. The rotor sails deliver auxiliary wind propulsion to the vessel – which has operated in conditions ranging from a tropical climate to arctic conditions in Europe, the Middle East, Asia, and Australia – resulting in the optimization of energy efficiency and a reduction in fuel consumption.
The rotor sails were installed onboard Maersk Pelican in August 2018. As part of the test, the aggregated total fuel saved from September 1, 2018, to September 1, 2019, was 8.2% savings. This is equivalent to approximately 1,400 tonnes of CO2. The savings were confirmed by comparing detailed performance information to a baseline established with full-scale measurements and computational analysis done for the vessel prior to the Rotor Sail installation.
Some of the companies are turning to liquefied natural gas .
The largest liquefied natural gas-powered ship launched just 2 months ago which will eliminate many of the problems associated with heavy fuel oils and result in about 20% fewer carbon emissions, but they are leaking large about of methane into the atmosphere, a much more potent greenhouse gas. At the end of the day, this fuel is still a fossil fuel. We could switch to biofuels like biogas or biodiesel, these are both fuels that are derived using renewable methods of converting biomass into fuel, but their ability to eliminate carbon emission is debatable. Some methods help to reduce carbon dioxide while others are worse for the environment than Fossil fuel.
Thankfully the shipping industry is already pretty efficient, but there is always room for improvement. This will make the investment and will cut into the shipping industry’s profits as fuel prices rise, but these are necessary moves to not only reduce but eliminate our carbon emissions.
Source – Real Engineering