Many shipping companies are experimenting with adding. Here's a design in which the sails are also solar panels.
EnergySail is a concept by Japan's Eco Marine Power that harnesses and stores wind and solar power to reduce fuel costs and pollution. It would work as an additional source of power to a ship's main engines.
The devices would be fitted on anything from large bulk ore carriers to cable-laying ships, ferries, and coast guard patrol vessels, according to the company. An automatic control system would orient the sails and panels to catch the wind and sun.
Large vessels such as oil tankers could see annual fuel savings of 10 to 20 percent. But when combined with optimized hull design, fuel cell technology, waste heat recovery, and an advanced electrical propulsion system, the EnergySail setup could generate fuel savings of 40 percent or more depending on the type of vessel, Eco Marine Power says.
The solar sails would work when the ship is docked and could be lowered if required. If enough energy storage modules are aboard, charged by the solar panels and main generators, the ship could forgo auxiliary diesel generators in port.
Emissions of sulfur oxides and nitrogen oxides would be reduced, but the concept is still being tested.
"We have started testing in a lab in Osaka and we will bring in other components of the system over the next few months," says Greg Atkinson of Eco Marine Power. "At the moment, we are focused on the control system and command interface testing."
Sea trials of the EnergySail system could start in 2013.