Massive wind turbines dominate the wind power industry, but entrepreneurs are now racing to build energy-making kites, sails and balloons. Here are five cutting-edge technologies.
Tow, tow, tow your boat is the idea behind attaching giant paraglider-shaped kites to cargo ships. The Hamburg startup SkySails has designed these giant textile sails large enough to cover the floor area of a ballroom. On a test voyage from Germany to Venezuela to America and then back to Norway, the skysail cut a vessel's fuel use by $1,000 a day.
Technology: The automated kite launches from a ship's bow and sails to a height of 300 to 1,600 feet to help propel the vessel. Ranging in size from 1,700 to 3,400 square feet, the double-walled kites can be deployed on a range of oceangoing ships, from shipping trawlers to mega-yachts.
Energy production/savings: SkySails estimates that its kites can cut a ship's fuel consumption by 10% to 35% a year on average, with the cost of the system amortizing in three to five years. The kites also help cut greenhouse-gas emissions by reducing use of the ship's engines.
Stage of development: The first pilot systems are in operation onboard a pair of cargo ships.
Reality check: A slowing global economy could make sales to international shippers a challenge.
NEXT: A little wind