Nippon Yusen KK and Nippon Oil Corp. have announced joint plans to build the first solar-powered cargo ship. It will be a 60,000-ton car carrier expected to be used by Toyota Motor Corp. The ship is scheduled to be completed in December.

The plans for the solar-powered cargo carrier did not require the creation of an entirely new vessel design. Instead, solar panels will be added on to an existing ship design. Each solar panel will be capable of generating 40 kilowatts and will help to conserve up to 6.5 percent of the diesel fuel cargo ships use to power engines for on-board electricity. Nippon Oil has estimated that the solar energy system will reduce carbon emissions by between one and two percent annually, saving approximately 20 tons.

Nippon Oil is primarily responsible for designing the solar panel system. Nippon Yusen KK, the largest shipping line in Japan, will invest 150 million yen in the project ($1.4 million). Nippon Oil plans to commercialize the design beyond the carrier ship destined for Toyota, however.

There are a few major issues that Nippon Oil will need to work through before it can shift into production mode. In addition to the normal wear and tear a solar panel might face on a land-based installation, salt exposure and vibrations are problems particular to ocean-going vessels that can cause significant damage to solar panels. So far, Nippon Oil does not seem to have a solution in place for either issue. However, difficulties in tying a solar power system into a propulsion system also serviced by a diesel engine seem have been resolved.

While Nippon Yusen KK and Nippon Oil's plans seem to be a step in the right direction, they are only a small step. Solar panels have been added to large shipping vessels in the past but have not been tied into the ship's system. Instead, prior uses of solar electricity have been restricted to powering living quarters for ships' crews. Connecting solar panels to the propulsion system is something new, but even with the extensive surface area of a supertanker to work with, the partnership has only been able to develop a design that can provide about six percent of a cargo ship's needs. It's not the designers' fault; the efficiency of solar power still remains a significant obstacle.

Photo by Flickr user Matti Mattila