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Is ODF Green?

Green IT is concerned with approaches to information technology that reduce the environmental impact from the manufacture, use and disposal of computers and peripherals.    Occasionally I am asked whether Open Document Format (ODF) has any relationship to “Green IT”.    This is an interesting question, and the fact that the question is asked at all suggests that Green IT goals are increasing playing a central role in decision making.

When an organization migrates from Microsoft Office and their binary file formats (DOC/XSL/PPT) and moves to ODF, they will immediately notice that ODF documents are much smaller than the corresponding Microsoft format documents.  This is a benefit of the ZIP compression applied to the contents of ODF documents.  It also reflects that fact that Microsoft-format documents, especially ones that have been edited and saved many times, tend to accumulate unused blocks in the file, blocks which are not used, but still bloat the file’s storage.

As an experiment I went to a prominent government web site (the US President’s www.whitehouse.gov) and downloaded all DOC files that were at the site, 293 documents total.  Then I converted each document into ODF format.  The percent reduction from moving to ODF was 66% on average.   Smaller documents means less disk storage required, less bandwidth required to transfer documents, less bloating of mail files with document attachments, etc.

Looking at the results in more detail, however, shows a more complex picture.  The following chart shows that although the average size reduction from moving to ODF was 66%, some documents were compressed 80% or more, while others were hardly compressed at all:

What is going on here?  A look at a scatter plot of original DOC size versus ODF size more clearly shows the pattern:

You can see here two trend lines, one of documents that are barely compressed at all, and another one where the compression rate is high.  Manual inspection of the poorly compressed documents indicates what is going on.  Some of the documents are dominated by the size of embedded image files with high color depth and resolution.   These images were already compressed, and so could not be compressed further, at least not by ODF’s ZIP compression.  However, in some cases the image files were of a resolution unnecessary for screen or casual print output.  Screen resolution is typically only 75 dpi.   Attaching images at 300 dpi or more wastes space, unless you know you are targeting high-resolution photo-quality output.  I think we’ve all been on the receiving end of an improbably large document, that when loaded contains relatively little content.  Often the culprit is a multi-megabyte image, with only a small cropped portion showing, but the entire image is stored.  There is nothing a document format can do to prevent user actions like this, but an intelligent editor (or plugin) could detect this and prompt the user to convert the image to a more appropriate resolution when saving.

So in summary, yes, a move to ODF will cause your documents to be far smaller than they were before, and that has advantages in terms of storage and bandwidth consumption.  But let’s be honest, when it comes to disk storage and bandwidth documents are not your biggest problem.  Graphics and video are far larger.

But if we look broader we see that the bigger Green advantage of ODF comes not only from the document size reduction, but from the alternatives ODF enables:

  1. Replace a paper-based workflow with an all-electronic workflow
  2. Replace a car or plane trip with electronic document-based collaboration
  3. Use a word processor that can run on your existing hardware rather than upgrading everyone to new hardware so they can run the latest MS Windows/MS Office.
  4. Use a less expensive word processor and by doing so free up resources to fund other Green initiatives in your workplace.


So what about OOXML?  Honestly, no one asked me that question before.  I think is a testament to the intelligence of my associates.  “Is it Green to throw out your 2005 laptop, buy a new, likely high-energy consumption one, pay for Windows 7 and Office 2010,  just so you can do the same work you did before?”  I think the answer is obvious.  Of course not.  For 99% of us the limitation on our productivity is not whether we have the latest software and hardware .  The limitation is our own skills and our working habits.     A word processor with a flashier interface doesn’t make you write better or write faster.  To think otherwise is to be like the amateur  golf player who thinks that their game will improve, if only they have the latest (and most expensive) gear.

But to satisfy the curiosity of those who care about OOXML, let me give you the results of the same documents, as converted to the DOCX format.  ODF still wins in this case.  The ODF files are 18% smaller on average than the equivalent OOXML ones.

{ 11 comments… add one }
  • M. Fioretti 2010/10/04, 6:46 am

    Well said, and same general point I made in “Does software pollute? Of course!” at http://digifreedom.net/node/81

    Keep up the good work,


  • twitter 2010/10/04, 8:50 am

    Laptop from 2005? I run Open Office every day on my Thinkpad X30 from 2002 thanks to Debian GNU/Linux. ODF also gives me real choices in software, like KDE and Gnome equivalents or Google Docs, which each have their own strengths.

  • Rob 2010/10/04, 11:46 am

    Hi Marco, good points. I suppose we can talk about direct and indirect effects. If a laptop made up of recycled materials, or materials that can be more easily recycled — these have direct effects that are easy to explain and understand. Ditto for computers that consume less power.

    And then indirectly, anything which reduces the rate at which you need to upgrade hardware also is a benefit.

    I think we reached the point a few years ago where the computing power on our desktops is “good enough”. The transition point can be seen when Microsoft started to look for clever ways to burn up processing cycles for eye candy (translucent windows and other Vista features) rather than things that actually increase productivity. The “problem” for the industry is that hardware and software does not wear out fast enough. In order to maintain their revenue stream, Microsoft and Intel and HP and Dell need to convince users that you must have a new machine every 3-5 years, whether you do or not.

    In other words, once everyone who needs a PC has one — the penetration rate for PC’s has saturated — then they only way the Wintel gang can preserve their growth rates is to either raise prices, increase manufacturing efficiencies or increase the turnover/upgrade rates for consumers.

  • David "Lefty" Schlesinger 2010/10/05, 12:31 pm

    For what it’s worth, I suspect it’s extremely unlikely that a personal computer purchased new today is going to have higher energy consumption than a roughly equivalent system purchased in 2005.

  • Rob 2010/10/05, 1:05 pm

    @David, I hear mixed news in that regard. On the one hand, there are improvements in power consumption. Technology such as solid state drives are more efficient than what we had in 2005.

    On the other hand, today GPU’s are the biggest consumers of power on many desktop machines, and we didn’t have them in 2005.

    And of course, you cannot run Windows 7/Office 2010 on a machine that is “roughly equivalent” to the one you had in 2005. I think you want to equate performance doing the end-user or business task (wordprocessing, say) not equivalence of the hardware.

    So I’d put the question as: Is the kind of PC you would buy today to run Windows 7 and Office 2010 more or less energy-efficient than the one you already have from 2005 that can run Linux and OpenOffice/LibreOffice just fine? And if it is more energy efficient, is the environmental impact from trowing out/recycling the old PC greater or less than the benefit from any energy savings?

  • David "Lefty" Schlesinger 2010/10/05, 1:47 pm

    These are all excellent questions, but they’d take a bit of research to actually answer, at least as posed.

    I happen to have a laptop I bought around 2005, specifically for the purpose of running Linux on it, a Lenovo X60s. I got it with an eight-cell battery—that puts out 14.4 volts at 5.2 Amps an hour—and with Ubuntu on there, I could get it to run for about four hours. (With XP, it would, in contrast, run for between six and seven hours: better power management).

    I don’t have Windows 7, nor a machine to run it on, but this illustrates some of the factors: it’s not simply the rate at which the hardware eats battery, it’s how efficiently the operating system allows the hardware to eat the battery. In that instance, XP was something like “half again as energy-efficient” as Linux, in some sense or other. This has probably improved on the Linux side, with better power management, but I don’t know how current Linices compare to Windows 7 in that respect.

    The X60s was a pretty high-end machine in 2005. For a reasonable comparison, I’d compare it—if I were going to do so—with the lowest-end current system on which I could reasonably run Windows 7…

  • Rob 2010/10/05, 2:21 pm

    Here is some data regarding MS Office hardware requirements:

    Microsoft states the minimum requirements for Office 2003 as:

    Pentium at least 233 Mhz. At least 128MB of RAM. 400 MB of HD space.


    And for Office 2010 the minimum requirements stated are:

    500 Mhz, 256 MB RAM, 3GB HD space


    Of course, “minimum requirements” might just mean the system can load and not crash. It doesn’t necessarily mean the system is particularly usable.

    So I think the question is this: is a Office-2010 minimum machine more energy efficient than an Office-2003 minimum machine?

    But I agree that power management is key.

  • Chris Rae 2010/10/05, 4:45 pm

    Hi Rob – the comparison between ODF and OOXML is an interesting one because, as you know, both of those are compressed formats. Are you able to share any more info about which applications you used to convert the original documents to ODF and OOXML?

  • Rob 2010/10/05, 7:28 pm

    @Chris, I added the DOCX comparison as a postrscript because some idiot on twitter complained that I had not mentioned OOXML. But DOCX isn’t the point of the post. As we both know, the interesting comparison is from DOC. Once a user upgrades to Office 2010 and DOCX they are less likely to move to ODF than someone who is still using Office 2003 and DOC format.

    But to answer your question, I did the conversions using OpenOffice.org 3.2.1 scripted from the command line for ODF and the OMPM for batch conversions to OOXML.

    However I do not think the exact software and versions explains away the results. I say that because I found and presented similar results at the OpenOffice.org Conference in Lyon back in 2006. That would have been the beta Office 2007 and OpenOffice 2.x. And that was with an entirely different set of test documents. (I used DOC files from Ecma TC-45).

    From my 2006 presentation: “ODF documents were smaller, on average 72% of the size of the OOXML document”.

    An easy test that anyone can try. Create and save an empty “hello world” document in and compare the size in ODF and OOXML. When I do that I also see that ODF is around 18% smaller (ODT 8,067 bytes versus DOCX 9,908 bytes).

    What would be interesting is to compare identical content across a range of document sizes and complexities and see if that leads to a better understanding of the file size differences.

  • Christophe Pradier 2010/10/06, 5:37 am

    Hello Rob,
    try the same comparison with PPT slideshows.
    When I did, converting a huge archive three years ago, I got amazing results. Some files simply get divided by fifty or more.


  • Alan Shea 2010/10/26, 2:03 pm

    For what its worth dept: I replaced my 2002-era P3 laptop one year ago with a Core 2 Duo. Out of curiosity I put it on a watt meter (“Kill A Watt”) to compare the two. The Core 2 Duo uses about 30% of the energy of the P3, while far outperforming it. Additionally and most interesting to me is that the new power supply uses 0 watts when not connected to the laptop, while the old power supply draws about 15-20 “vampire” watts. So overall I think newer computers are significantly more efficient. The big question is, what is the ROI for the improvement in efficiency? Not enough in my mind to justify an upgrade for that alone.

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