The new gadgetry at the International Consumer Electronics Show this week owes a lot to the crisp articulation of ever-increasing computer performance known as Moore’s Law. First proclaimed in 1965 by Intel’s co-founder Gordon Moore, it says that the number of transistors that can be put on a microchip doubles about every two years.
But a new descriptive formulation that focuses on energy use seems especially apt these days. So much of the excitement and product innovation today centers on battery-powered, mobile computing — smartphones, tablets, and a host of devices based on digital sensors, like personal health monitors that track vital signs and calorie-burn rates. And the impact of low-power sensor-based computing is evident well beyond the consumer market.
The trend in energy efficiency that has opened the door to the increasing spread of mobile computing is being called Koomey’s Law. It states that the amount of power needed to perform a computing task will fall by half every one and a half years.
The description of improving energy efficiency was the conclusion of an analysis published last year in the IEEE Annals of the History of Computing, with the title “Implications of Historical Trends in the Electrical Efficiency of Computing.” (An early draft [PDF] of the paper is here.) Jonathan G. Koomey, a consulting professor at Stanford University, was the lead author. His collaborators were three other scientists — Stephen Berard of Microsoft, Maria Sanchez of Carnegie Mellon University, and Henry Wong of Intel. (Mr. Koomey did not use the term “Koomey’s Law,” but others have.)
Like Moore’s Law, the significance of Koomey’s Law is more as an influential observation than a scientific discovery. Both are concepts that credibly measure what has happened and what is possible with investment and effort.
The analysis of the Koomey team goes back to 1946 and the Eniac, when computers used vacuum tubes rather than semiconductor chips, and traces the progress of computing energy-efficiency through 2009. (Here’s a chart.)
Koomey’s Law can be seen as unsurprising given the steady miniaturization of electronics — smaller circuits use less energy to accomplish the same computing tasks. “You can say it’s obvious, but it’s valuable to prove empirically that this is happening,” Mr. Koomey said in an interview on Tuesday.
Recognizing the energy-efficiency trendline — doubling of efficiency every year and a half, 100-fold in 10 years — becomes part of the thinking of engineers and executives, Mr. Koomey noted. It becomes an assumption in business planning and in imagining future products.
The efficiency trend allows for two design options — using less power to do intensive computing tasks, and spreading data-collecting sensors across the economy.
In a book to be published next month, “Cold Cash, Cool Climate: Science-based Advice for Ecological Entrepreneurs” (Analytics Press), Mr. Koomey sketches some of the applications in development or just around the corner. They include sensors that need no batteries because they “scavenge energy from stray television and radio signals,” and “tiny sensors inside products that tell consumers if temperatures while in transit and storage have been within a safe range.”
The curve of power-efficiency in computing, Mr. Koomey writes, will “help us minimize the energy use and emissions from accomplishing human goals” with environmental implications that are “profound and only just now beginning to be understood.”