CHIBA, Japan -- For years, TV makers competed over price and screen size. Now they're beating each other up over who is the most green.

The environmental friendliness of TVs is the new battleground for set manufacturers, at least from my interviews at Ceatec, a technology trade show taking place in the Tokyo suburb this week. Sony, for instance, has a 42-inch LCD TV from 2005 on display that consumes 131 watts while showing programs. Next to it is a 2008 set of the same size consuming 57 watts to show the same program.

Sharp also has two experimental TVs that run on solar power. One, a prototype 26-inch LCD TV, consumes only 40 watts of power, less power than a conventional light bulb requires. It functions on two solar small panels. Sharp is also showing off a 52-inch LCD TV that runs on a larger panel. It consumes only 220 kilowatt hours of solar power in an average year. (See photo below of the 26 inch.)

Sharp has come out with an application for its new slim LCD TVs that display family pictures or paintings from the Old Masters while in sleep mode. Running this screensaver-like device only consumes 60 watts. (See photo below.)

Meanwhile, Panasonic says it will reduce the power consumption in its plasma TVs by two-thirds by 2010 or 2011, said Toshihiro Sakamoto, president of Panasonic’s AVC Networks group in a meeting. The power consumption reduction will come in two ways. First, Panasonic will reduce the number of components in a plasma TV. Plasmas, which create images through chemical excitation, need more components than LCD TVs.

Second, Panasonic will try to direct more of the light coming from the light source to the screen itself. Doubling the luminance halves the electricity required to paint images on the screen, he said. Tripling it cranks down power to one-third.

“If the luminance effect is enhanced, we can dramatically reduce power,� he said.

Power consumption isn’t the only trick. Many TV makers continue to slim down their sets. Panasonic showed off a demo plasma that is under 27-millimeters thick, while Hitachi and Sharp have already released (expensive) LCD TVs that are in the same range. Sony has an organic light-emitting diode TV that is far thinner, but smaller.

Smaller TVs require fewer materials, which cuts down on petroleum in the manufacturing process. And they're lighter, making transportation easier, said Etsuhiko Shoyama, chairman of the board at Hitachi during a keynote presentation at the conference.

Hitachi earlier this year released thin LCD TVs in Japan that act as a convection oven, which dissipates heat better than fans or other devices. That allows the TV to be made thinner.

CHIBA, Japan -- Startups that make green homes be warned: Panasonic is coming. It will take a few years, but it’s coming.

The Japanese electronics giant has assembled a strategic plan to start making modular homes in about three to five years that will combine green construction along with sophisticated electronics to curb energy consumption, according to executives during a roundtable discussion at Ceatec, a large technology trade show taking place near Tokyo this week.

In a Panasonic demo at the show, sensors embedded in the ceiling adjust the air conditioner and lights depending on whether or not people are present. The sensor system (based around a technology called Beam Steering) also tries to determine which members of the household are in the room. If grandpa is there, for example, the heater might get cranked up.

“House to total solution, Panasonic is the only company to propose that,� said Ohtsubo Fumio, president of Matsushita Electric, which will officially change its name on a global scale to Panasonic on October 1.

This being a Panasonic demo, plasma TVs play a big part in the home of the future. That window in the back of the room in the photo? It’s a series of plasma TVs creating the illusion of a wonderful day. Another TV on a robotic track follows the models/occupants as they go from room to room so they won’t miss a minute of “America’s Got Talent.�

There is also a full-length mirror that turns into a TV that can also beam yoga lessons.

The scary part for green building startups is that Panasonic has the money and technology to pull this off. The company already has a construction division that makes modular homes in Japan. It also sells several upscale household appliances. It sells them in Japan, but will soon market them in Europe. LG, the South Korean conglomerate, has reaped huge amounts of revenue off of its upscale white goods over the last five years – take a look at the Best Buy supplement in your Sunday newspaper.

One of its marquee products is a sleeping system that slowly dims bedroom lights and plays soothing nature sounds as you go to sleep. The company also has a bathtub with insulation that can keep the water warm for hours. Energy and personal health (i.e., home exercise equipment and health monitors) are two of the four major areas of research for the company. Many of Panasonic’s appliances are on permanent display at a green home the company has erected in its showcase in Tokyo.

Other green housing companies just don’t have these kinds of resources. Building modular home factories is expensive. The industry in the U.S. is also in its infancy. This is the kind of news that can give VCs second thoughts.

On the other hand, Panasonic is a conglomerate and that can be a tough place to incubate new businesses. Additionally, the U.S. could be the last market it approaches, so everyone does have some breathing room.

Ohtsubo said that it will be at least three years before Panasonic will be ready to move forward.