Contrary to a report in the Japanese press on May 9, a Toyota spokesman says the company has no plans to make plug-in technology standard equipment on its entire lineup of hybrid vehicles.

An article in the Nikkei business daily Monday said Toyota was planning to make plug-in technology standard on its Prius lineup by 2014. A spokesman said Monday that was incorrect.

There's good reason why, he said: Plug-in technology adds a lot of cost and weight to cars, and the added benefits are too small to justify the extras, say Toyota officials.

Toyota initially was reluctant to offer a plug-in hybrid at all in the U.S. They expressed skepticism that buyers would want to pay several thousand dollars more for plug-in technology that would only give drivers 10 to 15 miles of electric-only driving per charge.

"We see this market as being a small percentage of our hybrid market," says John Hanson, a spokesman for Toyota. "We don't see it as a car for everybody."

But green advocates and techno junkies weren't happy with that response, and have pressured the automaker to launch a plug-in. Some geeky types even went so far to modify their Priuses so they could plug them into their own home outlets.

Too, there has been public relations pressure on Toyota from General Motors, which launched the Chevy Volt extended range electric car last year. Toyota has not been a believer in the Volt as a sound business proposition, citing the $42,000 price tag on the vehicle to pay for the battery required to propel the Volt up to 40 miles on an electric charge.

Toyota's first plug-in arrives in 2012, as a Prius. But the automaker has been open about having much more faith in its existing hybrid products and strategy: Introducing a family of Prius vehicles, adding one a size smaller and one a size larger than the current hatchback sedan.

Though Toyota is pursuing electric vehicles (EVs), and has even purchased a stake in luxury EV maker Tesla, the company is committed to hybrids as the mainstay of its green strategy. Pushing cars to full electric means adding bigger batteries, which adds weight. A plug-in system adds 400 pounds to a car, or the equivalent of two adult men sitting in your back seat during a commute. A heavier car means bigger brakes, springs and safety systems, adding more weight. And the heavier the car, the less fuel efficient it is. It becomes a case of diminishing returns.

The Prius dominates hybrid vehicle sales worldwide, but there is pressure from governments and environmental groups to keep pushing on EVs or at least plug-ins, like the Volt and Prius plug-in. Consumers are reacting with some hesitation to EVs, though, because of price, as well as performance and behavior of EVs in real world driving.

What are those real world differences?

The Volt stays in electric mode on 100% battery power until the battery is depleted. Then, a gas-powered motor kicks on to drive power through the battery to power the car, though the battery does not recharge itself during this period like a laptop computer or cell-phone. The fact that the car is not 100% dependent on a battery eliminates the anxiety many consumers feel when driving an EV that they will run out of juice and be stranded. Depending on driving conditions, a driver is expected to get up to 40 miles on a charge before the gas engine kicks on.

Traditional hybrid cars like the Prius or Ford Fusion Hybrid need to be babied a bit when accelerating, because pushing too hard on the gas pedal throws them out of battery mode and into gas-sucking mode.

The Nissan Leaf EV, which went on sale last Fall is a 100% electric car with a driving range of about 80 miles depending on how aggressively the driver is working the accelerator.

The plug-in Prius would drive on battery power for a while, though not for long -- just 13 miles on electric mode – and that's in perfect conditions. When it's cold outside, the plug-in sometimes acts just like a regular old hybrid without running in full electric mode at all.

Toyota isn't even sure how many plug-in vehicles it wants to sell in the U.S. The range could be anywhere from 5,000 to 40,000. The volume will affect how much the company will charge – fewer vehicles means higher prices.

Bottom Line: Prius Not Going 100% Plug-in

For now, Toyota seems to be betting that plug-in technology is a fad that will eventually fade away. The Japanese news agency report that reported that all Prius vehicles would be sold as "plug-in" in the U.S. was incorrect, according to Toyota officials.