Shipping is an integral element of the global economy. It’s also a significant contributor to greenhouse gas (GHG) emissions, contributing about three percent of the global total. While many other sectors are expected to decrease their emissions, emissions from shipping are projected to increase over the coming years.
If the industry doesn’t make changes to stop the growth of emissions, shipping could make up 17 percent of global carbon dioxide (CO2) emissions by 2050.
Despite these predictions, there may be significant potential to reduce shipping emissions. All by improving energy efficiency and embracing alternative fuels. According to the United Nations International Maritime Organization (IMO), making operational improvements and deploying existing technologies could decrease the energy consumption and CO2 emissions of ships by 75 percent.
Globally, the shipping industry has begun taking steps to reduce emissions. The IMO adopted in 2018 an initial strategy for reducing GHG emissions from ships. The plan envisions at least a 50 percent reduction in emissions by 2050 from 2008 levels. It also says that emissions should peak and start to decline as soon as possible.
What are some strategies the shipping industry can use to achieve improved energy efficiency and reduced emissions?
Making changes to the operation of ships could unlock significant energy savings. Reducing ship speed is one of the most beneficial adjustments operators can make.
Cutting ship speed by 10 percent can result in fuel savings of 20 percent, taking into account the increased voyage length resulting from reducing speed. It may be especially important to reduce speed when there are headwinds and adverse currents as well as when ships are nearing the coast.
Making port operation more efficient and reducing waiting time in ports can also reduce fuel use and cut time each voyage. Improving route planning could have a similar impact.
Another area to consider is capacity utilization. Logistics professionals should minimize unused space on ships to avoid wasted fuel. Ships often make return journeys with empty shipping containers, which is a significant missed opportunity. Coordinating with other shippers to make the most of return journeys could reduce the amounts of trips that vessels need to make.
Changes to ship design, such as improvements in the design of engines, power trains, propellers, flow profiles and more, can also improve fuel efficiency.
One example of this kind of innovation is the bulbous bow, a bulb protruding from the front of a ship just under the waterline. This protrusion changes how the water flows around the ship’s hull, reducing drag and increasing fuel efficiency.
As a ship moves through water, it creates a wake current that can create turbulence, increasing fuel consumption. An innovation called the Mewis duct, a channel with integrated fins located in front of the propeller, can streamline this water flow by guiding it toward the propeller blades. The fins in the duct also create a twist in the current that helps improve the energy efficiency of the propulsion system.
Another design improvement is the use of paints and coatings to reduce resistance. Specialized coatings can also prevent marine organisms from attaching to ships’ hulls. These organisms can create drag so preventing them from latching onto the boat can increase fuel efficiency.
Another major opportunity for reducing emissions is switching from diesel to cleaner fuels. Just as industrial engines can account for up to 65 percent of a warehouse’s electricity use. Therefore the engine of a ship is the center of its energy use. The shipping industry is starting to use more liquefied natural gas (LNG). That which burns more cleanly than diesel. Manufacturers can also equip ships with systems that capture “boil-off” vapor.
Yet finally the industry is even starting to explore using wind and solar energy to power ships.
The shipping industry has made some strides recently. However it still has a long way to go. Especially regarding improving energy efficiency and reducing emissions. So existing technologies and operational changes could contribute significant improvements. So embracing emerging technologies could improve shipping efficiency even further.
Emily Folk is a freelance writer and blogger from Lancaster, PA. She covers topics in conservation, sustainability and renewable energy. To see her latest posts, check out her blog Conservation Folks, or follow her on Twitter.