This is a talk I gave at Green:Net in March 2009

1. The Environmental Cost of Cloud
Computing: Assessing Power Use
and Impacts
Jonathan G. Koomey, Ph.D.
http://www.koomey.com
Lawrence Berkeley National Laboratory &
Stanford University
Presented at Green:Net
San Francisco, CA
March 24, 2009
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2. For users, the cloud offers
infinitely scalable computing
on demand
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3. So why should cloud users
care about power use?
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4. Power use strongly affects
costs for “in-house” IT
services (the alternative to
relying on the cloud) AND
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5. Cloud computing suppliers
have two inherent
advantages on power and
costs over “in-house” IT
(load diversity and
economies of scale)
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6. (As an aside, most people
think the true total cost for
“in-house” IT is far lower
than it actually is)
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7. Data centers, where the
cloud resides, are where the
world of bits meets the world
of atoms
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8. 8

9. The cloud uses electricity.
How much?
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10. World data center electricity
use, 2000 and 2005
Source: Koomey 2008
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11. How much is 152B kWh?
Italy
South Africa
Mexico
World Data Centers
Iran
Sweden
Turkey
0 50 100 150 200 250 300
Final Electricity Consumption (Billion kWh)
Source for country data in 2005: International Energy Agency, World Energy
Balances (2007 edition) 11

12. Trends push power use both
up and down
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13. Pushing power use up…
• Increasing demands for
– E-commerce
– VOIP
– Internet search
– software as a service
– video downloads
– resilience in the face of disaster
– regulatory compliance (e.g. Sarbanes-Oxley)
– IT-enabled business transformation
• More transistors on a chip + more RAM +
more volume servers
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14. Summary:
Delivery of IT services is
increasing rapidly
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15. Pushing power use down…
• Virtualization/consolidation
• Cooling and power constraints
• Recognition of constraints by the C level
• Metrics
– Servers + other IT equipment (Spec Power,
80 plus, E*)
– Site infrastructure
• Utility rebates (PG&E)
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16. Summary:
Information technology is
becoming more energy
efficient at a furious pace
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17. Internet electricity intensity
Electricity per GB transferred down 30% per year!
Source: Taylor and Koomey (2008) for 2000 and 2006 data.
Trends for 2000 to 2006 extrapolated to 2008 by JK. 17

18. Data center costs are strongly
affected by IT power use
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19. Annualized data center costs
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20. Two important equations
Power related terms
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21. In spite of our historical
progress, there’s still great
potential for improving the
energy efficiency of data
centers
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22. Many efficiency opportunities
Source: EPA report to Congress 2007 22

23. Improving the energy
efficiency of data centers is as
much about people and
institutions as it is about
technology
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24. Efficiency opportunities
• Improve asset management and
utilization (multiple benefits)
• Improve efficiency of components (e.g.
power supplies)
• Implement consistent metrics and track
over time
• Align incentives to minimize True Cost of
Ownership
• Think “whole system redesign” (RMI)
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25. Misplaced incentives
• Energy, efficiency, and performance metrics
not standardized
• Not charging per kW but per square foot
• Split accountability
– Who pays the bills, IT or facilities?
– Who bears the risk of failure?
• Hierarchy and culture differences
• Piling safety factor upon safety factor
• Not focusing on total costs for delivering
computing services
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26. Cloud computing suppliers
have at least two big
advantages on power and
costs over “in-house” IT
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27. 1) Diversity: spread loads
over many users,
improving hardware
utilization
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28. 2) Economies of scale:
implementing technical +
organizational changes is
cheaper and easier than for
small IT shops
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29. The biggest environmental
story about information
technology (IT) is not direct
electricity use (which is
relatively small) but how IT
affects efficiency in the
broader society
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30. Why?
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31. Moving electrons is always
less environmentally
damaging than moving atoms
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32. Example: paper vs. PDF
• Mass of paper = 5 g/sheet
• Mass of electrons to move a 1 MB PDF
file of that page (based on average
network electricity intensity of 7 kWh/
GB) is 1.7 x 10-5 g
• Ratio of paper mass to electron mass ~
300,000
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33. Conclusions
• The cloud is responsible for 1-2% of the world’s
electricity use.
• Absolute electricity use growing fast (doubling
every 5-8 years)
• IT services are growing much faster than
electricity use (doubling every year or two).
• Electricity productivity, defined as computing
services delivered per kWh, is increasing
rapidly and this trend promises to continue.
• The indirect environmental and productivity
benefits of IT are likely to be more important
than direct electricity use. 33

34. Key web sites
• EPA on data centers + 2007 Report to Congress
http://www.energystar.gov/datacenters
• LBNL on data centers: http://hightech.lbl.gov/
datacenters.html
• The Green Grid: http://www.thegreengrid.org/
• The Uptime Institute: http://www.upsite.com/
TUIpages/tuihome.html
• SPEC power: http://www.spec.org/power_ssj2008/
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35. References
• Koomey, Jonathan. 2007a. Estimating regional power consumption by servers:
A technical note. Oakland, CA: Analytics Press. December 5. (http://
www.amd.com/koomey)
• Koomey, Jonathan. 2007b. Estimating total power consumption by servers in the
U.S. and the world. Oakland, CA: Analytics Press. February 15. (http://
enterprise.amd.com/us-en/AMD-Business/Technology-Home/Power-
Management.aspx)
• Koomey, Jonathan, Kenneth G. Brill, W. Pitt Turner, John R. Stanley, and Bruce
Taylor. 2007. A simple model for determining true total cost of ownership for
data centers. Santa Fe, NM: The Uptime Institute. September. (http://
www.upsite.com/cgi-bin/admin/admin.pl?admin=view_whitepapers)
• Koomey, Jonathan. 2008. "Worldwide electricity used in data centers."
Environmental Research Letters. vol. 3, no. 034008. September 23. <http://
stacks.iop.org/1748-9326/3/034008 >.
• Taylor, Cody, and Jonathan Koomey. 2008. Estimating energy use and
greenhouse gas emissions of Internet advertising. Working paper for IMC2.
February 14. <http://imc2.com/Documents/CarbonEmissions.pdf>.
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