Supplying light is one of the most ubiquitous uses of electrical energy, and efficiencies in lighting design could have profound positive consequences for energy conservation. Mills (2005) reports on advances in "white light-emitting diode" (WLED) technology that offers promise. Light-emitting diodes are widely used in consumer electronics (typically red or green lights on clocks, coffee makers, etc.) but recent advances in development of those emitting white light offer opportunities for development of room lighting. Commercially available LEDs require 80% less power than the smallest energy-efficient compact fluorescent lamps. With solar-rechargeable batteries, WLED applications for use in developing countries offer a safe, economical, and energy efficient alternative to candles or other fuel-based lighting.
Reference
Mills, E., 2005: The specter of fuel-based lighting. Science, 308, 1263-1264.