This week a reader asks about how much the now open Northwest Passage will save in shipping emissions. This year, for the first time in recorded history, the Northwest Passage has become fully ice-free. This means that this Northern sea route around the Americas is now fully navigable, and will become increasingly so over the next few years. The Northwest Passage is expected to be a feasible alternative to the Panama Canal in 10 to 20 years, maybe sooner. But how much fuel and GHG emissions will it actually save to send container ships and supertankers into the arctic? Read on to find out…
The Panama Canal is limited to Panamax-sized ships (956 ft long, 106 ft wide, 39.5 ft deep, and 190 ft tall) so larger ships need to travel South, around Cape Horn or the Cape of Good Hope. If the Northwest Passage becomes a viable alternative it could potentially save a lot of fuel. But how much?
The distance between several European ports (Hamburg, Le Havre, etc.) and the Port of Oakland is 15,000 km by the Panama Canal. The distance around Cape Horn is 26,000 km and the distance around the Cape of Good Hope is 35,000 km. The distance through the Northwest Passage is only about 14,000 km.
So, with a distance of less than half the Cape Horn route, and much shorter than the Cape of Good Hope route, the Northwest Passage has potential to cut shipping times as well as cost and emissions. However this route will only be accessible in late summer for the near future and it will be more dangerous due to icebergs. But, since larger ships will be able to pass, this route might also be more efficient than the Panama Canal.
Ship efficiency depends on several factors, including speed, the amount of water displaced by the hull, how efficiently the ship is packed (oil tankers are more efficient than container ships for this reason), and how full a ship is during each leg of the trip. A ship that is empty on the return trip must take on ballast water and the emissions of the return are attributed to the cargo from the initial trip.
It is logical that a large ship that is traveling relatively slowly is more efficient than a ship that is half as big and traveling much faster. So you could send the big ship on one trip in the time it takes the smaller ship to do two trips and you would carry the same amount of cargo, but with less fuel used. So, despite being 1,000 km longer, the Northwest passage would probably require the same, or less fuel to travel as the Panama Canal would. Add to this that ships in the Panama Canal are not traveling at an optimal speed, meaning that they will take longer and consume more fuel.