SAN FRANCISCO -- If computers didn't continually improve in energy efficiency, they would have never got off the ground.
 
If you stacked a Google data center with computers that consumed the same amount of energy as ENIAC, the computer developed at the University of Pennslyvania during and after World War II, it would consume as much power as Manhattan, said Mark Mills, the founder of Digital Power Capital at the ThinkGreen conference taking place in San Francisco.
 
If you wanted an iPhone, Mills said, it would be the size of a steamer trunk, while the relay station for cell signals would be the same size as the Washington Monument.
 
There's a direct relationship between energy consumption, efficiency and progress, said Mills during his keynote speech. The short version is as follows: Energy allows us to do stuff. Engineers make these devices more efficient, which drops the price, which in turn drives demand. More devices lead to huge explosions in energy consumption. Today's servers consume far less power than ENIAC, for example, but there was only one ENIAC. Over 250 million PCs ship from factories a year.
 
It also depends on what form you get your energy. Some forms are more dense than others. If you took a standard economy car and rigged it with lead acid batteries, it could go twenty miles, he said. If lithium-ion batteries were used, the car could go 100 miles, which is the range Nissan has put on its electric commuter car coming in 2010 (see Green Light post). If the same volume were given over to ethanol, it would got 400 miles. If you filled up with oil, it would go 700 miles. Oil is incredibly dense, so it will continue to have a market.
 
"That's why airplanes run on oil," he said. Solar-powered Boeing 777s will never happen, he added. Sure, you might be able to rig up a test plane, but it couldn't carry cargo or passengers.
 
Another way to look at the same problem is the cost of BTUs. The equivalent of a barrel of oil filled with wood would cost $20. A barrel of oil with the same amount of energy would cost $50. A barrel of ethanol would cost $70. A barrel of electricity would cost $200. For a data center, a barrel of power, which has been conditioned with power supplies and other equipment, would cost $10,000, he said. A barrel of laser energy? $200,000. In other words, oil costs less.
 
And make no mistake, oil demand continues to rise. If economic growth returns, the annual growth in demand will be like adding a country the size of France to the grid every year. "It's a big country," he said. The world consumes 2,500 barrels of oil a second right now. If you stacked up those physical barrels, the stack would grow at 5,000 miles an hour, he said.