The evolution of light: LEDs

Keith Butcher, an energy services representative with Southern Municipal Power Agency, talks about the history of lighting and LEDs at the North Branch area Chamber of Commerce’s Lunch and Learn meeting July 27.
Photo by Derrick Knutson

Light is something that many people take for granted: All a person has to do to have light in their home is simply flip a switch.
Keith Butcher, an energy services representative with Southern Municipal Power Agency, of which North Branch Water and Light is a member, explained during a North Branch Area Chamber of Commerce Lunch and Learn meeting July 27 that the evolution of harnessing the power of light has been a process that has happened over thousands of years, and one of the most recent advances is LED light.
First, Butcher gave a bit of a history lesson on light. He noted that archaeological evidence shows that about 70,000 years ago people may have been hollowing out rocks so they could transport burning embers from place to place. By 4,500 B.C., oil lamps were being used. About 1,500 years later, the Egyptians started implementing candles as light sources. Skipping forward many generations, the fluorescent tube was first used in 1934, then came halogens in 1959, followed by CFLs in 1976, and then the LEDs “really took off in about 2006,” Butcher said.
He then explained how LEDs work.
“LEDs emit light through a process called electroluminescence — when you pass an electric current through a material it generates light,” he said. “That’s what the LED is. You’re passing current through this medium. The medium itself is made of two parts: positively charged and negatively charged components. You have your anode and your cathode. The positive layer has holes, or openings, that electrons can fill, and the negative layer has all these free electrons in it. When you pass a current through it, the electrons go from the negative side and fill in the holes on the positive side, and it’s this current transfer that creates the light.”
The advantages of LEDs are many.
“LEDs are notable for being extremely long-lasting products,” according to, a website where consumers can buy lights and learn about lighting products. “Many LEDs have a rated life of up to 50,000 hours. This is approximately 50 times longer than a typical incandescent, 20-25 times longer than a typical halogen, and eight to 10 times longer than a typical CFL. Used 12 hours a day, a 50,000-hour bulb will last more than 11 years. Used eight hours a day, it will last 17 years.”
For people who are conservation-minded, and who want to save some on their energy bills, LEDs are a good choice.
“The primary driver (to switching over) is cost savings,” Butcher said. “When folks pull out their old equipment and go with an LED, which uses less electricity, that means their utility bills are lower. Then there are the environmental benefits. For every kilowatt hour that we save, that means it’s a kilowatt hour that we then don’t have to generate. Since most of our energy generation still comes from fossil fuels, by preventing the need to burn those fossil fuels we’re mitigating climate change impacts and we’re preventing other environmental impacts.”
As LED lighting technology increases, the products become better and more varied, Butcher noted. Early on, he said a common complaint was the color or brightness of the LEDs. Now, lighting engineers have found ways to make it softer. A person could be in a bar with hanging lights, and they might not even notice they’re LEDs. Butcher said more whimsical lighting options are available with LED lighting, such as night-lights that look like opened books. And LED technology can be paired with smartphones, which means a person could use his her or phone to turn on and off or dim the lights in their home.
Butcher did note that LEDs are still generally more expensive than some of the other lighting options, but there are rebate programs, one of which is offered through North Branch Water and Light. Anyone who would like information about those rebates can visit the Water and Light website at

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