i4Energy Seminar: Electrical Efficiency Trends of Computation over Time

Jonathan Koomey [Stanford University]

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All i4energy talks take place at noon on Fridays in the Banatao Auditorium on the 3rd floor of Sutardja Dai Hall, UC Berkeley. These talks are free, open to the public and broadcast live on-line at  mms://media.citris.berkeley.edu/webcast the day and time of the event. Questions can be sent via Yahoo IM to username: citrisevents.

The spring series is online at http://www.citris-uc.org/events/i4e-spring2010.

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This talk will describe long-term trends in the electrical efficiency of computation that enabled the development of laptops and other mobile computing devices.  If these trends continue, they presage continued further improvements in battery powered computers, sensors, and controls.

The electrical efficiency of computation (measured in computations per kilowatt-hour, or kWh) grew about as fast as performance for desktop computers starting in 1975, doubling every 1.5 years, a pace of change comparable to that from 1946 to the present. Computations per kWh grew even more rapidly during the vacuum tube computing era and during the transition from tubes to transistors but more slowly during the era of discrete transistors. In 1985, Richard Feynman identified a factor of one hundred billion (10e11) possible theoretical improvement in the electricity used per computation.  Since that time computations per kWh have increased by less than five orders of magnitude, leaving significant headroom for continued improvements.

About the speaker
Jonathan Koomey is a Project Scientist at Lawrence Berkeley National Laboratory, a Consulting Professor at Stanford University, and was (for the Autumn semester of 2009) a visiting professor at Yale University‚Äôs School of Forestry and Environmental Studies.  Dr. Koomey holds M.S. and Ph.D. degrees from the Energy and Resources Group at UC Berkeley, and an A.B. in History of Science from Harvard University.  He is the author or coauthor of eight books and more than 150 articles and reports on energy efficiency and power technologies, energy economics, energy policy, environmental externalities, global climate change, and critical thinking skills, and is one of the leading international experts on the economics of reducing greenhouse gas emissions and the effects of information technology on resource use.  His latest solo book is the 2nd edition of Turning Numbers into Knowledge:  Mastering the Art of Problem Solving (http://www.analyticspress.com).