CO2 produced by shipping
Shipping produces 5% of the world's CO2. It is not included in the Kyoto protocol.
Shipping is expected to increase, there are 70,000 ships with orders for 20,000 more. They use 200 million tonnes of fuel per year. The annual carbon dioxide emissions from shipping is between 600 and 800 million tonnes of carbon dioxide.
Aircraft make up 2% of the total CO2 emissions and they are not part of the Kyoto protocol either.
At a typical 85% occupancy, the energy consumption of a tourist class liner is 121 kWh per 100 pkm – more than twice that of the jumbo jet. Source
Now that fuel prices have gone up, the shipping industry is looking at ways to save fuel. The areas of research are:
Sails - potentially save 20%
Slowing down from 25 to 12 knots - save 10-30%
New propellers - save up to 20%
Coating the surface of the hull with bubbles - save 20%
Nuclear-powered vessels are common in the navy and are increasingly being suggested for merchant fleets; more ships are using liquefied natural gas (LNG) to fuel their engines, which are significantly cleaner than marine diesel ones; fuel cells are being developed for marine applications; solar power is being used for onboard equipment; wind assisted propulsion is being reinvented, ranging from the use of large kites to pull vessels along to the reintroduction of high-tech sails that can work with other power options and provide 30% of the energy required.
At the same time, new designs of ship hulls are being introduced that reduce friction and so reduce energy consumption. Low-friction paint coatings are also becoming available.
We can also expect to see pentamarans – fast cargo ships with five hulls that fill the gap between expensive air transport and slow traditional ships.
Future fuel for shipping
The options are not easy:
Clean petroleum fuel - reduce sulfur but not particles nor green house.
Methane - still releases greenhouse gases, CO2 and Methane.
Bio-oil - Is there enough of it? Particles from the diesel?
Hydrogen - storage needs to be solved
Nuclear - Is there enough? Can waste be disposed safely. Accidents. Terrorism risk. Stealing fuel from a warship is unlikely, but a cargo ship would be much easier.
Wind power - is there enough?
Wave power - is there enough?