Two Japanese companies are developingsolarpanels to help power a cargo ship and reduce carbon-dioxide emissions.

The project by Nippon Yusen, the largest shipping company in Japan, and Nippon Oil Corp. will install solar panels on a 60,000-ton carrier, saving up to 6.5 percent of the diesel fuel used to propel the engines, reported Reuters.

The panels will be able to generate 40 kilowatts of electricity for the carrier, which will be used by Toyota Motor Corp. Solar power has been installed on ships before, but it typically provides juice for the living quarters, rather than for propelling the ships.

The solar-panel array is expected to reduce the cargo ship's carbon-dioxide emissions by 1 percent to 2 percent, or 20 tons, per year.

The shipping industry has faced strong criticism for its contributions to the rising levels of greenhouse-gas emissions worldwide. The amount of greenhouse gases emitted by ships is under debate.

At the World Ports Climate Conference in July, the amount was pegged at between 5 percent and 20 percent. The world's human population produced about 49 billion metric tons of greenhouse-gas emissions in 2004, according to the 2007 Intergovernmental Panel on Climate Change climate-change report, putting ships' emissions at between 2.45 billion and 9.8 billion metric tons.

The conference last month resulted in a declaration to reduce emissions, which was supported by representatives from 55 ports. The International Association of Ports and Harbours plan to draft measures to monitor and cut emissions will be discussed at another meeting scheduled for November in Los Angeles.

Nippon Yusen plans to spend 150 million yen ($1.4 million) to install the solar-power system, which is being designed by Nippon Oil. The project is scheduled for completion in December.

The aviation industry is eyeing solar power as an alternative power source for planes, though not for a jumbo passenger jets at this point.

In July, a French company, Lisa Airplanes, said it is engineering a plane that will rely on solar power for takeoff and for running onboard instruments during flights (see Trina Solar Powers French Planes).

Last Sunday, QinetiQ said its unmanned solar-powered plane flew 82 hours and 37 minutes, breaking a world record of 30 hours and 24 minutes set by another unmanned aircraft in 2001. QinetiQ's Zephyr flew at the U.S. Army's Yuma Proving Ground in Arizona.

The U.S. Department of Defense and the United Kingdom's Ministry of Defense funded the demonstration flight and the development of Zephyr, which is built with thin-film solar panels made from amorphous silicon. At night, the aircraft relies on lithium-sulphur batteries to stay afloat.

Meanwhile, Sunrise Solar Corp. in San Antonio, Texas, has introduced a solar-array to replace the traditional sunroof on a car, the company said this week. The solar sunroof charges car batteries. The company plans to market the product through Barker Communications, a light-emitting diode and solar-electronics company in Houston.

Toyota also has been tinkering with the idea of installing solar arrays on car roofs. The carmaker plans to roll out a Prius that will have its own solar roof for powering air conditioning and other onboard electronics (see Prius to Get Solar Panels?).

Fisker Automotive also plans to begin producing the Karma, a plug-in hybrid with a solar panel on its roof, next year (see Automakers Vie for Green Cred).