LED Fiat

Lux fiat may become LED fiat.

From a total cost of ownership (TCO) measure, LEDs have beat other lighting technologies for a while. Not surprising since solid state devices almost always win economically over time. Now LED prices are dropping to the point that they can compete with the purchase price of other lighting technologies.

An emerging idea is to use LED in streetlights and street signs. In the streetlight market, the energy winners are low power sodium and LED lights. However, because LEDs last 10-15 years, with the right timer controller, an LED streetlight requires no maintenance for at least 10 years. That gives LED streetlights the clear advantage over low power sodium lights.

The following table lists annual power consumption and operating costs for commercially available streetlights. It does not include initial cost and installation of the streetlight pole and light, but those costs differences are negligible over ten or twenty years of use. It makes many assumptions about energy and labor costs and typical bulb life. However, it is fair to say that, of all these lighting technologies, LEDs are dropping most quickly in price.

Energy Use and Cost for Residential Streetlights

Light	kW-hrs Per Year	Operating $ Per Year
Mercury Vapor	1,104	$108
Metal Halide	690	$94
High Power Sodium	460	$63
Low Power Sodium	345	$65
LED	376	$43

There are something on the order of 10 million streetlights in the United States. Add street signs (like the signs you see on the side of the freeway giving mileage to the next few exits), and the number of fixtures probably doubles.

As with traffic lights, where LED usage has reduced energy consumption and operating costs, expect to see LED streetlights and street signs near you soon.