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A Japanese shipmaker has said it plans to launch the world's first large electric ferry - the latest innovation aimed at reducing greenhouse gas emissions.

A subsidiary of heavy machinery giant IHI Corp. has completed a basic design for a 30-metre (99-foot) long ferry that could carry 800 passengers, powered by rechargeable batteries, according to a company spokesman.

While smaller battery-powered boats are already in use, IHI's ferry would be the world's first large plug-in vessel. It would emit no carbon dioxide or nitrogen oxide. We also aim to slash fuel costs," he said.

The ferry would be able to cruise some 120 kilometres (74 miles) on a charge of six to eight hours, he said.

The group's shipbuilding subsidiary IHI Marine United Inc. plans to launch the ferry in around 2015, when it expects high-performance rechargeable batteries to be available at a lower cost.

The total battery capacity would be around 5,000 kilowatt hours -- more than 300 times greater than that of a small electric vehicle currently in use, the spokesman said.

The price is likely to be some 60 percent higher than that of a conventional ferry.

Earlier this year Finnish firm Wärtsilä and IHI Marine concluded a co-operation agreement for Contra-Rotating Propeller (CRP) systems developed by IHIMU to be incorporated into Wärtsilä’s propulsion solutions on board diesel-electric driven ships.

The IHIMU CRP system is said to achieve 10 percent better propulsion efficiency compared to conventional diesel-electric propulsion systems, and is applicable to all vessels from small ships to large LNG carriers.

"This efficiency improvement translates into significant fuel savings, thus enabling a short return on investment as well as reduced greenhouse gas emissions," Wärtsilä said.