In its strive towards net-zero emissions come 2050, the shipping industry should steer a different course from the one that is focusing only on the CO2 emissions from the fuel and focus on the whole life cycle of the ship, says Danish naval architecture consultancy, OSK-ShipTech.
According to OSK-ShipTech, the industry must focus on the broader picture in the CO2 emissions debate. As it explains, the ferry industry has been leading the way when it comes to implementing alternative fuels and a transition to battery propulsion.
According to Anders Ørgård, Chief Commercial Officer of OSK-ShipTech:
Reducing the direct CO2 emissions should remain a priority, but shipowners cannot turn a blind eye on the indirect contributors of CO2 emissions: notably the manufacturing process of a ship and all the components it is made of
In fact, OSK-ShipTech has discovered that for a full-electric ferry, powered by climate-friendly electricity, non-operation-related CO2 emissions could reach well in the excess of 55% of the total CO2 emissions produced during the ship’s 20-year life cycle
Rather than exclusively focusing on the emissions from operations, shipowners should make a cradle-to-grave life cycle analysis. A life cycle analysis offers the opportunity to develop a build strategy, reducing the emissions during both construction and operation, thus further optimising the ship’s operational life
says Ørgård.
OSK-ShipTech’s study included a life cycle assessment of Fanølinjen’s 2021-built, full-electric ferry GROTTE; a 50-metre-long double-ended ro-pax vessel operating the 12-minute Esbjerg-Nordby shuttle service. Notwithstanding the short distance it covers, GROTTE effectively sails 12 hours per day.
To make long positioning trips possible, most electric ferries are still equipped with diesel engines. Experience from operating full-electric ferries has taught that they operate for approximately 90-95% of the time on electricity. For this reason, they also need backup power from other energy sources. As per publicly available data, the climate-friendly electricity used to power GROTTE has an emissions intensity of 0.0187kg CO2/kWh, compared to the 0.297kg CO2/kWh of the electricity generated from a typical mix of renewable and conventional energy sources.
OSK-ShipTech has calculated that during its entire lifespan, from cradle to grave, GROTTE will produce 2,508 tonnes CO2-eq from the ship’s operation with 1,833 tonnes CO2-eq attributable to the manufacturing of the vessel. As the ship and its materials will be recycled upon demolition, scrapping of the vessel will have a positive CO2-eq footprint of 1,124.54 tonnes.
The tonne CO2-eq from GROTTE’s operation still surpasses the tonne CO2-eq from the ship’s construction by a good margin, according to Ørgård.
Our analysis clearly illustrates that a zero-emission ship doesn’t exist at all. To put it simply, one can no longer ignore the CO2 emissions generated from manufacturing, which can be more than 50% of the cradle-to-grave CO2 footprint in some cases
As the steel structure accounts for nearly 40% of the CO2 footprint in a ship’s construction, a strategy should be developed to focus on the hull and steel structure already in the design stage.
