This year's Nobel Prize in physics was awarded to three scientists who advanced LED lighting technology in the 1990s. Their work was part of a longer-term trend of rapid improvements in LEDs.
The improvements have come so fast, in fact, that engineers came up with a law to track the changes. Everyone knows about Moore's law, which says that the number of transistors in a computer chip (and, therefore, its computing power) doubles every 18 to 24 months. It has a less famous cousin called Haitz's law. It says that every 10 years, the power of LED lighting packages will increase by a factor of 20, while the cost of these packages, per unit of illumination, will fall by a factor of 10.
The law is named after Roland Haitz, who made the forecast in 2000. And so far, the industry has actually exceeded his expectations:
The solid dots represent the number of lumens — a unit of illumination — produced by an LED lighting package. And notice that this is a logarithmic scale — each time you go up from one notch to the next, the amount of illumination (or the cost) goes up by a factor of 10.
In the late 1990s, the brightest LED lights you could buy produced around 10 lumens of light. By 2005, you could get LED packages that produce 100 lumens. Recently progress has accelerated, so that you can now get LED packages that produce 1,000 lumens of light. If current trends continue you'll be able to buy 10,000-lumen LED lights in a few years.
For comparison, a 100-watt incandescent light bulb produces around 1,700 lumens. So LED lights are becoming nearly as bright as conventional lighting sources.
Even better, the cost of these devices, per lumen, is falling rapidly. In the 1990s, it would have been crazy to try to light your house with LEDs. You would have needed hundreds of LEDs, which would have been way too expensive. But just like computer chips, LED lighting is providing more and more value for the dollar. If current trends continue, LED light bulbs will soon be not only more powerful than conventional light bulbs, but cheaper too.
As my colleague Brad Plumer has written, this could be a huge deal for energy efficiency, as LEDs have always converted energy into light more efficiently than conventional lighting technologies. This could be a huge boon in the developing world, where people might be able to capture energy with solar panels during the day and then use it to light their homes at night.
On the other hand, as light gets dramatically cheaper, the rich world might just consume a lot more of it. Our grandchildren might decide they like their homes and offices to be dramatically brighter than they are today. Perhaps ceilings of the future will be speckled with dozens of tiny LEDs that can make rooms as bright as broad daylight.