Cargo ships to be propelled by kites
This is very cool
:
One of the first large cargo ships in 100 years to cross the Atlantic with the help of the wind will set off from European shores this month on a voyage which is due to make maritime history.
When the 10,000-tonne Beluga Skysail is well clear of the land, it will launch a giant kite, which wind tunnel tests and sea trials suggest will tug it along and save 10-15% of the heavy fuel oil it would normally burn. If the journey from Bremen in Germany to Venezuela and back proves successful, it could become common to see some of the largest ships in the world towed by kites the size of football fields.
After the Beluga Skysail has been in service for a while, larger cargo ships may 
sail with even larger kites, which could result in fuel savings of up to 35 percent. That's nothing to sneeze at, since 95 percent of global shipping is done by sea:
It is estimated that commercial shipping, which traditionally uses the most polluting fuel, uses nearly 2bn barrels of oil a year and emits as much as 800m tonnes of CO2, or 4 percent of the world's man-made emissions. Shipping also pollutes the atmosphere with more sulphur dioxide than all the world's cars and lorries.
Small, incremental contributions like this can go a long way toward cleaning up the environment and conserving our dwindling petroleum resources. Nothing's a panacea, of course, but even small improvements like this can make a huge cumulative difference.
This article gives some more technical details and says the towing capacity of the larger kites is equivalent to a 6800 HP engine.