Researchers in Japan have developed giant, retractable sails that can be used on cargo vessels and other large ships to maximize wind energy while simultaneously cutting down on fuel consumption. Created as part of the Wind Challenger project, the sails stand at 20 meters wide (about 65.62 feet) by 50 meters (164 feet) high and are said to reduce oil costs by an average of 30 percent when used alongside a traditional engine. Rather than sticking to the canvas construction of traditional sails, these feature a five-piece telescoping design and an aluminum / plastic construction allowing them to retract in the event of hazardous weather.

It isn't exactly a cheap venture: each sail is estimated to cost around $2.5 million, though it's not hard to see how an investment up front could ultimately cut freight costs over time. Kiyoshi Uzaza, assistant professor at University of Tokyo, believes that initial cost could be recouped after 5-10 years. With initial research completed, Uzawa and his group hope to build a half-size prototype within the next two years to ensure such large sail structures are feasible. If all goes well, you could see merchant vessels utilizing the technology by 2016.