In the fall of 2003, the boy band TOKIO embarked from Tokyo on a journey to cover the entire coastline of Japan in a 1997 Daihatsu Hijet minivan that they had refit themselves with a solar roof-panel and a battery-powered engine. Driving in shifts of two, the five members have, as of the most recent installment of their TV show “Tetsuwan Dash,” traveled along the coast of the Tohoku region, Hokkaido, the entire Japan Sea, Kyushu, Okinawa, Shikoku, Chubu and Kansai for a total of 15,603 km. The vehicle, which is called Dankichi, is now somewhere in Mie Prefecture.

Each episode of their trip ends when the battery runs down after sunset. The practical limits of a solar-powered car are clear, but the fact that they’ve made it this far and required servicing only once is nevertheless impressive. When we talk about alternative vehicles we talk about using ethanol, electricity or hydrogen, all of which require energy to produce in the first place. At present, solar cars may be impractical for many of the things we use cars for, but they are almost completely self-sufficient.

Like Dankichi, solar cars in general are looked upon as little more than novelties and thus unworthy of the attention of major automobile makers. Until recently, oil prices were so low that car companies didn’t have to think about new types of vehicles, but everyone has now reached the conclusion that those days are gone and won’t be back again. With the controversy over “peak oil” — the theory that all underground petroleum reserves will soon be tapped — and the inescapable dangers of greenhouse gases, ecological countermeasures are imperative. But since even China defers to the market these days, solutions are being driven by economics. A recent article in the Asahi Shimbun said that as a reaction to the late 1970s oil crisis, more than 800,000 solar-heating units were installed in Japanese homes during the 1980s. As the oil crisis abated and energy prices dropped, sales of solar units dipped.

The decline was not just economic in nature. Solar cultivated a bad image because of media reports about distributors using unethical sales tactics. One scandal can do immeasurable harm, and thus “solar” took on a negative connotation that had nothing to do with its function. That was OK with utilities since they still haven’t found a way to charge people for sunshine. Japan’s electric power and gas companies have their own suggestions for saving the planet and making money in the process.

They also have their own clever catch phrases, which help reduce fairly complex technologies to simple ideas that can be sold in 30-second TV spots. Tokyo Electric’s Ecocute may be the smartest. The commercials, which feature actress Kyoka Suzuki and a little boy who has a creepy erotic crush on her, basically sell the idea of the all-electric house. “Cute” is a homonym for kyuto, which means “hot-water supply.”

As the ads point out, about a third of the energy consumed by the average home is used to heat water. The problem with the all-electric house is that while it’s cheaper to maintain than one in which gas and electricity are both used, it indirectly produces more CO2. That’s because the electricity is produced far away in an oil-burning or nuclear power plant, and about 60 percent of the energy is lost when it is transmitted to the home through the power grid. Ecocute utilizes the heat pump concept by extracting ambient heat from the air, and is thus more efficient for heating water than conventional electric methods.

But Tokyo Gas won’t be outdone. Veteran actor Masakazu Tamura plays up his epicurean image by preparing sumptious meals in ads for Eco-jozu, which means “eco-proficient.” Gas loses no energy when transported. Eco-jozu uses a “latent heat recycling system”: the energy that is lost when water is heated is trapped and used again, thus increasing the efficiency rate to 95 percent. But that’s not all. Tokyo Gas also promotes Eco Will in its witty series of ads featuring young actor Satoshi Tsumabuki and historical figures like Marco Polo and Nobunaga Oda who pop out of his wardrobe. Eco Will is aimed at homes that consume a lot of hot water by utilizing a cogeneration system that recycles wasted heat as electricity.

All these systems are more energy efficient than conventional water heating systems, but they’re not perfect. According to the ecology organization CASA, Ecocute’s efficiency drops considerably in the winter when there’s less heat in the air, which means a home may still need gas or conventional electric heating. Tokyo Gas likes to point out the inefficiency of electricity, but gas is more expensive and the price can only go up. The government will partially reimburse consumers who install these systems since they help Japan reduce greenhouse emissions in line with the Kyoto Convention, but we’re talking only ¥30,000-¥40,000 against an outlay of millions.

CASA says that solar technology, even in its present form, is more efficient and less polluting than any gas or electric-power heating system, but the utilities have shown little interest. Tokyo Gas has developed a solar collector for apartments, but it can only be used in conjunction with Eco-jozu systems. And forget about Tokyo Electric. In Germany, sales of self-contained solar systems have skyrocketed since the Russian gas dispute of 2006 because German utilities pay high prices for surplus electricity generated by homes. Tokyo Electric pays very little, so there is even less of an economic incentive for homeowners to go solar.

As long as solar systems remain a novelty they will also remain expensive, and that’s the main reason people are reluctant to buy them.

They’re promoted by local governments and nonprofit organizations, neither of which can compete with energy companies in terms of PR power. Then again, TOKIO is probably more popular than Suzuki, Tamura and Tsumabuki combined, so it seems a shame that no one is capitalizing on the success of Dankichi, the little solar car that could.