Leds or conventional public lighting? A comparative exercise on energy efficiency and environmental impacts
Leds of conventionele openbare verlichting? Energie-efficientie en milieueffecten vergeleken
26 May 2012, PDF |
52 pages |
Struijs J, den Hollander HA, Alferdinck JWAM, Kruijter NJ de, Hoek JP van
RIVM Report 607343001
Public lighting with energy efficient leds (light emitting diodes) may help to reduce energy consumption in the Netherlands. The limitations of this new technique need however further research. In this report luminaries based on led technology are compared with luminaries with conventional compact fluorescent lamps and high pressure sodium lamps. In order to meet the Kyoto protocol the Dutch government stimulates the use of more energy efficient lighting. Public lighting serves traffic safety, social safety and livability. In order to fulfill these services, several demands are put on public lighting, for example illuminance should be sufficient. With respect to compact fluorescent lamps, which are favorable in residential areas because of the warm white light, the led alternative requires 15 to 27 percent less energy. Compared to high pressure sodium lamps however, leds need more energy. Because of the fast development it is espected that leds will perform better in near future. The efficiency of leds would improve considerably if the spectral sensitivity of the eye is taken into account. Currently, the guidelines for public lighting are a matter of debate because the spectral sensitivity of the eye is ignored. In daylight the eye has an optimal sensitivity for green-yellow light but at low light levels for blue-green. As less blue-green is required for sufficient visibility, it is more energy efficient. The drawback is that people do not appreciate this light colour as comfortable. Moreover, switching between green-yellow and blue-green light sources requires few minutes of adaptation time. During this period of time, the eyesight is limited.