From windmills on land, to sailboats at sea, humans have a long tradition of seeking to harness the energy of the wind. However, in terms of nautical propulsion, humans probably first employed "elbow grease" — first using paddles and poles while floating on logs, and eventually using oars in sea galleys manned by dozens and sometimes even hundreds of rowers. Many centuries later, during the late 1800s, an increasing portion of large seagoing vessels were powered by coal-produced steam, eventually replaced by diesel power. More recently, surface ships and submarines have used electricity generated by onboard nuclear reactors, particularly by the navies of developed countries.
But in that interim, between the age of the oar and the age of oil, sailing ships ruled the waves. Their usage peaked in the 19th century, culminating in the beautiful "tall ships", such as the clippers that transported goods between the Old World (England and Europe) and the New World (primarily United States). These magnificent vessels, with their sail cloth and rigging snapping in stiff ocean winds, were the true pioneers of green energy, being independent of petroleum and coal resources.
Such wind propulsion may soon see a renaissance, now that the costs of diesel fuel, uranium, and oil are rising at sporadic yet significant rates. More specifically, merchant ships may eventually be powered by wind energy more than any other source. But this does not mean a return of sails and masts; rather, each commercial merchant ship would use an enormous kite.
The first such ship is the 132-meter MV Beluga Skysails, which is scheduled to make its maiden voyage in January 2008, traveling from Hamburg to Venezuela, then to Boston, and back to Europe. It will be pulled by a computer-guided kite measuring 160 square meters, shaped like a paraglider, and attached to a 15-meter high mast at the front of the ship. This huge kite will be flying up to 300 meters above the ocean surface, allowing it to catch the stronger winds found at the higher altitudes. That additional force will be essential for pulling the 10,000-metric ton ship through the water.
Critics point out that such kites can only supplement, not replace, the ships' primary diesel-based propulsion. Also, these kites systems are expensive; the Beluga's costs about 500,000 euros. Nonetheless, the fuel savings are expected to be at least 20 percent, which translates into $1600 per day. In recent years, fuel costs have tripled for shipping companies, and can easily exceed $500 per day for just a small vessel. The two German companies who developed this pioneering project, SkySails and Beluga Shipping, expect that the Beluga's kite system will pay for itself in only 3-4 years. In the future, with refinement of the kites and their computer control systems, fuel savings may eventually reach 40-50 percent.
The two firms are already planning to install even larger kites on larger ships. They are not the only organizations looking to the future, because other shipping companies have expressed strong interest in buying similar systems for their own fleets, provided that the Beluga's maiden voyage demonstrates the system's viability. In fact, the target is to have 1500 vessels equipped with kites by 2015.
If all goes as planned, we may once again see oceangoing ships leveraging the wind power provided by the rotation of the earth, and thus reducing the emission of carbon dioxide, sulfur dioxide, and other greenhouse gases.