'Vindskip' cargo ship uses its hull as a giant sail

Story highlights

  • A Norwegian design would use the high sides of a cargo ship as sails
  • The designers say it could save as much as 60% on fuel costs, 80% on CO2 emissions
  • The world's first VindSkip could slip into the water by 2019

(CNN)While it's a form of transport few of us see, shipping packs a punch as a polluter.

According to a recent study, shipping accounts for around 3% of global CO2 emissions. Not surprising when you consider that the engines of the world's estimated 90,000 cargo ships are in use 24 hours a day while traveling.
Futuristic concepts for container ships powered by alternative energy range from windmill-powered propellers to banks of vertical metal sails. Even though most are still on the drawing board, one concept i