Japan may be one of the world leaders in developing renewable energy, but the country's green tech sector seems to be either making too much noise, or too little.

Gas-electric hybrids are now the best-selling cars in Japan, AFP reports, but now the government is confronting the fact that hybrids may be too quiet.

A hybrid's quiet hum can take some getting used to for the driver used to the constant rumble of an ordinary gas guzzler. But the real danger is for the visually impaired, and some blind Japanese are worried about hybrids because they're so hard to hear, even for people used to navigating by sound.

The Japanese government called a meeting of police, auto industry representatives and members of organizations for the blind to talk it over.

The panel agreed they should consider adding some kind of noisemaker to hybrid vehicles, though they didn't agree on what it would be, what sound it would make or how they could make it loud enough to protect the blind but not bother the neighbors.

While Japanese hybrids are apparently too quiet, the country's wind turbines may be too loud. As they spin, turbines create infrasonic waves, or sounds too low in frequency for humans to hear.

Some, like American scientist Nina Pierpont, say that the vibrations, though noiseless, cause "vibroacoustic disease." The Japanese are aware of the malady and are worried about the increased incidence of infrasonically-induced headaches and insomnia in those living near wind farms.

Despite the rising concern, there's still a shortage of research into "wind farm syndrome." The most prominent high-level report to date was a 2005 study by the Danish government suggested that older turbines could create excessive vibrations though, if the wind farm used newer turbine designs, vibrations could be minimized.

The booming Japanese wind sector is expected to be resistant to redesigns, but government ministers have signaled they will look more closely at the vibracoustic issue so that wind power isn't doing more harm than good.