Absolute Power


Fun Facts for the New Year

This blog originally posted on the Low Power Engineering Community 1/14/10. 

Happy 2010 to everyone out there! To start the year out right, I thought it would be interesting to pull out a few “fun facts” about power and power consumption that we can chew on as we brave the new year.

For example, the average (resting) human body requires around 100W of power to keeping all systems running (heartbeat, cell division, a few brain waves, etc.). That seems a little high for “standby mode,” doesn’t it? But considering that we’re made up of between 10 trillion to 100 trillion cells, each consuming about 1 pW of power, it’s about the right ball park. Compare that with a 100 million-gate SoC today that might consume 10 to 100W of power, and we can see that we’re still perhaps 1,000,000x away from matching nature’s power efficiency, even ignoring the obvious mismatch in potential between a living cell and the proverbial “ASIC gate.”

On the higher-power front, a reasonably healthy human can generate about 1KW of peak output power during exercise. That 10:1 ratio between peak power and standby power isn’t very impressive compared to my smart phone, which has probably a couple of orders of magnitude better ability to really turn down the juice in standby, thanks to the magic of power shutdown. Imagine if we could do that with our bodies! Maybe an interesting insight into relaxation, meditation, and that old “Kung Fu” episode where Kwai Chang Caine gets stuck in the mine shaft…

And how about the REALLY big and powerful? An average car? 100 KW. A “supercar” (400+ hp)? 300 KW. An aircraft carrier? 200 MW. Nuclear reactor? 1 GW, which is only slightly less than the 1.21 GW required to power the famed DeLorean time machine in “Back to the Future.” And the estimated average power consumption of the human world this year? About 18 TW (1 terawatt is 1012 watts).

So we run the gamut from picowatts (10-12) to terawatts (1012). 24 orders of magnitude in power. What a year so far!

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