In a fantastic example of clean tech trickle-down, a recent technology show in Japan debuted a variety of fuel-cell wheelchairs aimed at the elderly and those with limited mobility. Battery powered wheelchairs are limited by shorter range, long charge times, and the eventual death of the battery, which can strand chair users in a potentially hazardous situation.

But fuel cell and fuel cell-electric hybrids overcome many of these issues, extending range to some 10 hours of use, or some 37 miles of travel, allowing chair users to keep up with all but the fittest able-bodied companions. Hybrid designs, again revealing some technological trickle-down, allow efficient electricity to power devices at low speeds, before turning to hydrogen power as range increases.

Though the technologies employed in these new chairs have been available for nearly a decade, it took the continued aging of Japan's population to create the economic incentive for these new products to be created. As demands and market pressures change, more and more niche green technologies will find their way into mass market products.

(Image and hat tip: TreeHugger)