Toyota has also jumped on board. Next year, Toyota will start offering AC electric outlets as an option on its popular Prius hybrid in Japan so drivers can plug in household appliances.
The idea was born from watching victims of Japan's March 11 quake using the Toyota Estima hybrid van as a source of emergency electricity when the power was knocked out.
It is the only Toyota model currently offering a standard AC outlet. But Toyota wants to add them to the Prius next year and eventually across the hybrid line-up. The disaster may boost electric-car sales, said Takeshi Miyao, an analyst at consulting company Carnorama in Tokyo.
"Electric cars now have the chance to demonstrate how useful their batteries can be," Miyao said. "Electric vehicles have an advantage, more than ever." Tokyo Electric Power has said electricity shortages may lead to further scheduled outages after the quake crippled its Fukushima Dai-Ichi atomic power plant in the world's worst nuclear accident in 25 years.
Other reactors in Japan have also been halted for inspections and maintenance, exacerbating a national power shortage.
Even so, energy use at night, when electric-car owners typically charge their vehicles, only reaches about 50 per cent of available supply, according to the utility.
"Charging electric vehicles during the night shouldn't be a problem at all," Miyao said. "What's necessary is to cut back during peak times."
Using the car's battery to run appliances is done with a 30cm device Mitsubishi sells for an extra $230. It plugs into a socket in the i-MiEv's interior and converts the battery's direct current into alternating current for the appliances, which plug into the other side.
Nakamura said Mitsubishi had intensified battery-development efforts since the March disaster. The Tokyo-based company aimed to introduce a battery that could discharge as much as 1500 watts by the end of this year, he said."We noticed a shift in the public's focus, and we are speeding things up."
Hideaki Watanabe, Nissan's head of zero-emission vehicles, said it planned to unveil a discharge system for its Leaf electric car next month.
Nissan spokesman Shiro Nagai said although the car's battery had a capacity of 2400 watts, the carmaker had yet to decide on its discharge capacity.
He said although Japan's overall motor vehicle sales had declined after the earthquake, orders for the Leaf had held steady.
Sales of the model in Japan, which fell in March and April amid output disruptions caused by the disaster, rebounded in May to 472 vehicles from 177 the previous month.
Watanabe said Nissan had sold about 8200 Leafs globally as of mid-June, after introducing the car in December.
"Even though we had to halt production after the quake, sales are going well," Nagai said.
For now, the technology may be of limited use to people living in high-rise apartment buildings, who have no way to connect their cars to their kitchen appliances. "Right now, it's impossible," said Toshitake Inoshita, a spokesman at Nissan. "The infrastructure to carry that electricity up to a room on the 12th floor needs to be developed first."
Mitsubishi spokesman Kai Inada said the technology wasn't meant for regular use in homes just yet.
"We only have plans for the electricity to be used in emergency situations, or for people going camping," he said. Mitsubishi's i-MiEV, which went on sale in April last year, uses a battery supplied by Lithium Energy Japan, a joint venture between Mitsubishi and battery maker GS Yuasa Corp.
The battery can be fully charged in seven to 14 hours and can power the vehicle for 160km, Mitsubishi says.
It has sold about 4000 i-MiEVs in Japan and exported more than 10,000, including vehicles supplied to French carmaker PSA Peugeot Citroen.
The Japanese company plans to add eight hybrid and battery-powered models by 2015, beginning with its M model, on sale in Japan this week.
Nissan plans to introduce a total of seven electric models in addition to the Leaf in the six years to fiscal 2016.
It is targeting sales of 1.5 million electric vehicles over the next six years with its French partner, Renault.
In addition to serving as an emergency power source, Nissan's Watanabe said electric vehicles could help conserve energy during peak demand times.
"They can store energy during the night, when demand is low, and that stored energy can be used at peak time," Watanabe said.
"The battery's ability to store power adds value to the car even when it's not running."
The Leaf's lithium-ion batteries, supplied by battery maker Automotive Energy Supply, a venture between Nissan and NEC, take about eight hours to be fully charged to 24 kilowatt hours. A full charge can power the car for an estimated 200km, according to Nissan.
The company plans to begin making batteries for the Leaf in Smyrna, Tennessee, and Sunderland, England, next year. It will start making them in Portugal in 2013 and also plans production in France. Nissan aims to make 500,000 batteries a year by 2015.
"The Leaf already has the capacity to supply all the electricity you need for a regular household for two days," Watanabe said.
"Customers can expect more than that in the new cars to come."
- Bloomberg
