by Mark Boyer
Light bulbs have always been pretty inefficient, even those that have a rep for using less juice, like LEDs. Because of the energy conversion process, they consume more energy than they actually need to illuminate. But what if we told you that there was a light bulb out there, just waiting to be invented, that could produce more energy than it consumes? A group of researchers at MIT have figured out how to develop LED lights that wildly eclipse the efficiency of any other bulb. In fact, they successfully tested a LED light with an efficiency of 230 percent!
The key to increasing the power conversion efficiency, according to MIT researcher Parthiban Santhanam and his co-authors, is to decrease the applied voltage. When the voltage is halved, the input power is decreased by a factor of four. (The inverse is also true — the brighter LED lights are, the less efficient they become.) In effect, if you decrease the input power enough, the LED’s efficiency can increase to more than 100 percent, thus achieving what’s known as “unity efficiency.” When that happens, the light bulb will produce as much or more energy than it takes to power it, giving you the ultimate bang for your buck.
The only problem? As you may have guessed, significantly lowering the input power creates a very weak LED bulb. In their tests, the MIT researchers succeeded in generating about 70 picowatts of light from 30 picowatts of energy — an efficiency of 230 percent! That’s a remarkable achievement, but still a miniscule amount of light. For now, there really isn’t any practical application for a super-efficient 70-picowatt bulb, but according to PhysOrg, the researchers hope the breakthrough could open the door to new advances in energy-efficiency electromagnetic communication.