Ready for Transfer

NREL’s Street Lights Composed of Narrow Wavelength Light-Emitting Diodes

Dept. of Energy

Laboratory: National Renewable Energy Laboratory (NREL)

Technology: Street Lights Composed of Narrow Wavelength Light-Emitting Diodes

Opportunity: This technology is available for licensing.


The increasing affordability of light emitting diode (LED) technology has revolutionized the way we illuminate our homes, buildings, and streets. LEDs use less than a quarter of the energy and last 25 times longer than traditional incandescent lighting, and thus promise tremendous economic and energy-saving benefits to both industrial and residential applications. Despite this promise, however, scientists are still ironing out the unforeseen side effects of LEDs in some applications. Such side effects include deleterious properties of blue light affecting the circadian rhythms of both humans and wildlife, as well as excessive light emission from LED street lamps contributing to heightened levels of light pollution in the sky.

To effectively alleviate these problems, researchers at NREL have developed a unique luminaire technology that utilizes a number of discrete, narrow bandwidth LEDs that individually emit light over blue, green, red, and amber wavelengths. Optics within the luminaire then mix the light to produce a uniform spectrum white light that produces vastly improved color rendering ability within the illumination area. This yields gentler, safer acceptance by the human eye and has tremendous benefits for those working and moving around at night.

Furthermore, by using narrow bands of visible wavelengths, optical notch filters in the luminaire’s design can be used to filter different colors of light and dynamically tune the spectrum to meet the needs of the environment in which it is placed. For example, sidewalk and street lights can be tuned to change their spectrum through the course of the night to enhance amber and red hues, thereby softening total exposure to blue light in the late hours, when humans and animals are most sensitive to it. Such tunability can also significantly reduce light pollution, thus enabling astronomers to do their work with minimal ambient light disruption.


  • Significant improvements to color rendering capability from LED lighting at nighttime
  • Tunable spectrum capability to provide different types of light in different environments
  • Reduction of light pollution
  • Continued energy and economic savings for light generation


  • Street and sidewalk lighting
  • Zoos and nature preserves
  • Road construction
  • Sports venues
  • Airports, dockyards, and other locations of round-the-clock outdoor work

Contact: For more information about this LED technology, please contact Bill Hadley at

To view the original technology listing, visit