The push for energy-efficient lighting in the developed world focuses on replacing wasteful incandescent bulbs with compact fluorescents and LEDs. In developing regions, however, kerosene lanterns still bring dim nighttime light to an estimated 1.6 billion people.
Off-grid lighting is a growing area of focus for social entrepreneurs eyeing opportunities for "green" technologies in developing markets.
Engineers, start-ups, nonprofit groups, and venture capitalists involved are working on portable flashlights and fixtures powered by solar panels and even bicycle-like pedaling contraptions.
Safe and affordable lighting can be key to development efforts in poor communities. With better light, people have more time to work and study. Hazards of fire from kerosene accidents diminish. And in war zones, potential attackers may be better recognized or deterred.
Lighting innovations created for emerging markets are also bouncing back to the developed world. For a photo gallery of the products being built, click here.