Information Systems for Environmental Sustainability

IT, Resource Productivity, Environmental Preservation, and the Fourth Industrial Revolution

Cloud Computing Cuts Carbon?


CDP released a report last month estimating the energy and carbon emission impacts of a cloud computing architecture (public and private) versus dedicated IT. According to the model, a shift to cloud computing results in an estimated carbon reduction of 50% by 2020.

Where do these carbon (and energy) savings come from? They are a function of two parameters in the model that are assumed to vary across the three architectures: power usage effectiveness (PUE: ratio of total power used by data center to power used by IT) and server utilization rates. Note that for PUE, the lower the number the better, while the opposite is true for server utilization.

While it’s a good first start, it would be helpful to put some confidence bars around the assumptions and check the sensitivity of the final results to various scenarios (best case, worst case, etc.) Also, it’s not clear what the adoption scenarios look like and how, precisely, the PUE’s were forecast. Finally, it’s interesting to contrast these optimistic CDP estimates with what Greenpeace has said about cloud computing.


Author: nigelpm

Associate Professor of Information Systems, Stephen M. Ross School of Business, University of Michigan - Helping organizations to navigate digital transformation.

3 thoughts on “Cloud Computing Cuts Carbon?

  1. Dear Nigel,

    I will have a look at this tomorrow, perhaps I can find some of the information that you are looking for.

    Forecasting, like predicitng the future, is a very imprecise science. Depending on the forcasting method it is possible to “prove” a very large universe of scenarios. It does raise alarm bells.

    From Grant Howard (AIS SIGGreen)

  2. Dear Nigel,

    I have found two academic articles that bear relevance, the first is called “Green Cloud Computing: Balancing Energy in Processing, Storage, and Transport” (2011) and the abstract indicates that “under some circumstances cloud computing can consume more energy than conventional computing where each user performs all computing on their own personal computer (PC)” – this is an interesting finding.

    Baliga, J.; Ayre, R.W.A.; Hinton, K.; Tucker, R.S.;
    Dept. of Electr. & Electron. Eng., Univ. of Melbourne, Melbourne, VIC, Australia

    This paper appears in: Proceedings of the IEEE
    Issue Date: Jan. 2011
    Volume: 99 Issue:1
    On page(s): 149 – 167
    ISSN: 0018-9219
    References Cited: 59
    Cited by : 1
    INSPEC Accession Number: 11698368
    Digital Object Identifier: 10.1109/JPROC.2010.2060451
    Date of Publication: 30 August 2010
    Date of Current Version: 17 December 2010
    Sponsored by: IEEE

    Network-based cloud computing is rapidly expanding as an alternative to conventional office-based computing. As cloud computing becomes more widespread, the energy consumption of the network and computing resources that underpin the cloud will grow. This is happening at a time when there is increasing attention being paid to the need to manage energy consumption across the entire information and communications technology (ICT) sector. While data center energy use has received much attention recently, there has been less attention paid to the energy consumption of the transmission and switching networks that are key to connecting users to the cloud. In this paper, we present an analysis of energy consumption in cloud computing. The analysis considers both public and private clouds, and includes energy consumption in switching and transmission as well as data processing and data storage. We show that energy consumption in transport and switching can be a significant percentage of total energy consumption in cloud computing. Cloud computing can enable more energy-efficient use of computing power, especially when the computing tasks are of low intensity or infrequent. However, under some circumstances cloud computing can consume more energy than conventional computing where each user performs all computing on their own personal computer (PC).

    The second article is called “Energy-Efficient Cloud Computing” (2009) and seems to support cloud computing energy savings.

    Andreas Berl1,*,
    Erol Gelenbe2,
    Marco Di Girolamo3,
    Giovanni Giuliani3,
    Hermann De Meer1,
    Minh Quan Dang4 and
    Kostas Pentikousis5

    + Author Affiliations

    1Fakultät für Informatik und Mathematik, University of Passau, Innstr. 43, 94032 Passau, Germany
    2Electrical and Electronic Engineering Department, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
    3HP-European Innovation Centre, HP IIC (Italy Innovation Centre), Italy
    4School of Information Technology, International University in Germany, Bruchsal, Germany
    5VTT Technical Research Centre of Finland, Kaitoväylä 1, FI-90571 Oulu, Finland

    *Corresponding author:

    Received July 28, 2009.
    Revision received July 28, 2009.


    Energy efficiency is increasingly important for future information and communication technologies (ICT), because the increased usage of ICT, together with increasing energy costs and the need to reduce green house gas emissions call for energy-efficient technologies that decrease the overall energy consumption of computation, storage and communications. Cloud computing has recently received considerable attention, as a promising approach for delivering ICT services by improving the utilization of data centre resources. In principle, cloud computing can be an inherently energy-efficient technology for ICT provided that its potential for significant energy savings that have so far focused on hardware aspects, can be fully explored with respect to system operation and networking aspects. Thus this paper, in the context of cloud computing, reviews the usage of methods and technologies currently used for energy-efficient operation of computer hardware and network infrastructure. After surveying some of the current best practice and relevant literature in this area, this paper identifies some of the remaining key research challenges that arise when such energy-saving techniques are extended for use in cloud computing environments.

    I cannot find any academic articles that directly confirm or refute the CDP study in question. I also cannot determine who the actual researchers are in this CDP study, the only contact from the researching company is Stuart Neumann
    Verdantix Worth noting is that “This study was supported by AT&T For more information on AT&T Cloud Solutions go to

    Also, at the end of the report is an “Important Notice” which among other things states “CDP does not guarantee the accuracy or completeness of this information. CDP makes no representation or warranty, express or implied, concerning the fairness, accuracy, or completeness of the information and opinions contained herein. All opinions expressed herein are based CDP’s judgment at the time of this report and are subject to change without notice due to economic, political, industry and firm-specific factors.”

  3. Grant,

    Thanks for finding these and posting the abstracts.
    Seems to confirm my overall sense that assumptions of how computers are used are important in determining energy use and carbon emission differences across different IT architectures. The results of the Baliga et al. (2011) study appear to depend on how individuals use computing resources.


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