Red and green diodes had been around for several years, but adding blue diodes allowed a mix that could produce practical white-light LED bulbs.
LEDs use less energy than do other forms of lighting, including compact fluorescent (CFL) and incandescent bulbs. A typical LED bulb can produce around 83 lumens per watt—a measure of how much brightness you can get from a unit of electrical power—compared with 67 for a comparable CFL bulb and 16 for an incandescent.
LEDs produce light by passing electric current through a semiconductor, whereas incandescent bulbs pass current through a wire filament until it glows from the heat. The wasted heat energy is chiefly why incandescent bulbs are so much less efficient. Most varieties of the incandescent light bulb have been phased out in the United States. (Related: “U.S. Phase-Out of Incandescent Bulbs Continues in 2014.”)
LEDs also last about 30 times longer than incandescent bulbs do, according to the Energy Information Administration, and many LED bulb products promise up to 25,000 hours of use—more than 17 years if you used one for about four hours a day.
One of the main barriers to adoption of LEDs has been price: A typical bulb can cost more than twice as much as a comparable CFL. But LED prices are coming down, and use is growing. A recent report from energy research firm IHS noted that “adoption of LEDs is happening at a faster pace than ever before” and predicted that from 2014 on, LEDs would have the largest revenue share of all lighting technologies.
The lighting transformation is not only in residences. LEDs are also being used for street lights, public holiday and decorative displays, commercial buildings, and other large energy users. According to a recent report from the research firm Navigant, installation of LEDs in street lighting worldwide is expected to grow from 13.2 million bulbs in 2014 to more than 116 million in 2023. (Related: “Separating Myth From Fact on LED and CFL Light Bulbs: Five Concerns Addressed.”)
LEDs also hold promise for bringing light to the more than 1.5 billion people around the world without access to an electricity grid, the Royal Swedish Academy of Sciences noted. Indeed, several proposed solutions to energy poverty include the distribution of LED lights, particularly solar-powered ones. For example, the Solar Electric Light Fund, a nonprofit National Geographic grantee, has installed LED bulbs at hospitals and homes in villages across Africa.