Transoceanic freighters haul 80 percent of the world’s commercial goods. But those boats inadvertently carry destructive cargo as well. An empty ship can suck up more than 10 million gallons of water to stay balanced as it crosses the open ocean. Upon its arrival into another port, the crew pumps the ballast water and any small animals or plants living in that water—sometimes thousands of organisms per gallon—into foreign harbors, where they invade and damage local ecosystems.

It was all smooth sailing for seafaring extremist Ken-ichi Horie. That wasn’t exactly what he was hoping for when he set sail for Japan from Hawaii in the world’s most sophisticated wave-powered boat, named the Suntory Mermaid II

With oil prices recently breaking the psychologically important barrier of $100 per barrel, commuters aren't the only ones feeling the heat. Cargo vessels are responsible for moving 98% of all intercontinental goods, and a transatlantic crossing on fully-loaded 200-meter ship is not light on the diesel consumption. So far, at least two companies promise to deliver a technology not seen on massive ocean-going ships in quite some time: the sail.