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    Case Study: OPM’s Carbon Footprint Analysis


    In early 2013, the Federal telework team of the U.S. Office of Personnel Management (OPM) collaborated with its Sustainability Team within the Facilities, Security, and Contracting group on a project to use General Service Administration’s (GSA) Carbon Footprint survey to measure the impact of telework on a number of commute related metrics. Our efforts were intended to provide an example of how to conduct this type of analysis and show the kinds of results an agency can expect.

    After becoming aware of Carbon Footprint, OPM’s Federal telework team met with Jennifer Hazelman at GSA. She willingly briefed us on the tool and participated in a Telework Week 2013 webinar to inform the telework community about the tool. Prior to meeting with Ms. Hazelman, our team was not aware that the survey had already been used by OPM’s Sustainability Team to develop OPM’s annual inventory of greenhouse gas emissions (GHGs) as required by Executive Order (EO) 13514, “Federal Leadership in Environmental, Energy, and Economic Performance.” The discovery of this parallel work illustrated a principle we have shared with agencies – which intra-agency collaboration is essential for assessing telework since telework touches so many aspects of an agency, from energy and commuting to recruitment and retention.

    Through this collaboration, in a short time we were able to leverage an existing, rich source of data and the expertise of our Sustainability Team to produce the following analysis for OPM.


    Executive Order 13514 was signed by President Obama on October 5, 2009. Among other requirements, this E.O. tasked agencies with appointing a Senior Sustainability Officer, developing an annually updated Strategic Sustainability Performance Plan, establishing a greenhouse gas reduction target, and developing plans to create more sustainable buildings, water use, energy efficiency, and pollution prevention. Greenhouse gases are broken into three categories based on the source. The Scope 3 category includes “greenhouse gas emissions from sources not owned or directly controlled by a Federal agency but related to agency activities,” including employee travel and commuting.

    To assist agencies with annual greenhouse gas reporting requirements, GSA developed the Carbon Footprint Tool and Survey ( The survey asks a number of questions about employee commute behavior in order to assist agencies with calculating their Scope 3 emissions. Agencies select a minimum of 8 standard questions, but can also choose from an additional 22 optional questions and may customize up to 3 questions. These flexibilities enable agencies to design their survey to capture telework behavior and frequency data. With this data, agencies can make comparisons between teleworkers and non-teleworkers on a variety of energy, environmental, and commute outcomes.

    This survey has already been utilized by a number of agencies across the Federal Government, and others are planning to begin using it or continue to use it annually. Since the telework question is not automatically included, it is important to be in contact with the survey point-of-contact (POC) at your agency to ask that it be placed in the survey. To find your agency’s POC, you may contact Carbon Footprint at

    Methods, Calculations, and Assumptions

    The Carbon Footprint Survey was administered by email to OPM employees in December 2012. In total, 2,861 employees participated and of these participants 933 reported teleworking at least one day per week.

    The survey data contained the following data elements used for the analysis:

    • Number of days per week an employee indicated teleworking. Employees could select telework in lieu of a commute method on a question asking about the forms of transportation they used each day in a typical work week.
    • Estimated annual greenhouse gas emissions, measured in metric tons of carbon dioxide equivalent (MT CO2e). This was calculated by the Carbon Footprint tool using the data provided by respondents to the survey. Each respondent had an associated emissions quantity.
    • Daily commute miles traveled. Employees were asked to list the number of miles traveled on each day of a typical work week.

    These data elements were used to compute the following:

    • Average weekly commute miles traveled by telework frequency category. Computed by adding together the reported daily commute miles. Then an average number of miles were calculated for each telework frequency category (e.g., 1 day per week, 2 days per week). The one-way average miles reported in the survey were then doubled, with the assumption that an employee traveled an equal distance in the trips from and to home.
    • Average annual commute miles traveled by frequency category. Computed using average weekly commute miles traveled and multiplying by an average of 46 work weeks per year.

    Calculations for estimated impact of telework:

    Two estimates were produced. One reflected the given distribution of teleworkers and non-teleworkers found in the survey. The second estimated what would happen if no survey participant’s teleworked.

    • Total agency annual commute miles were calculated for each telework frequency category by multiplying its average annual commute by the number of employees, then summing them up and doing the relevant conversion to fuel or dollars. In other words, a weighted calculation.
    • To get total annual fuel costs and gallons consumed, the following conversions were used.
    • Annual gallons of gasoline. Divide average annual commute miles traveled by an average U.S. light duty vehicle fuel economy of 23.5 mpg.
    • Annual fuel costs. Multiply gallons of gasoline by an average Dec. 2012 U.S. gas price of $3.38 per gallon.

    These calculations were repeated, but instead considering a scenario where all 933 teleworkers did not telework. We multiplied the total number of survey participants (teleworkers + non- teleworkers) by the average figures for non-teleworkers.

    Computing the difference between non-teleworkers and teleworkers across each category (commute miles, gallons of gasoline, fuel costs, and emissions) yields the savings from telework.

    As a last step, it was necessary to account for the fact that if teleworkers were to stop teleworking, many might choose to use other forms of transportation other than driving alone. We produced a discount rate based on the number of respondents that reported driving alone (either in their own vehicles or Federal owned vehicles). OPM found that 57 percent drive alone overall, and 44 percent drive alone in non-Federal vehicles (and thus pay their own gas bills). Multiplying the savings by these discount factors yielded our final savings estimates.


    Through this analysis, OPM found that the 933 OPM employees who reporting teleworking in 2012 saved an estimated annual:

    $274,500 on gasoline
    104,000 gallons of gasoline
    2.4 million commute miles
    578 MT CO2e of greenhouse gases

    Telework Frequency
    0 days 1 day 2 days 3 days 4 days 5 days
    Weekly Commute Miles (two way) 271 269 178 119 34 14
    Annual Commute Miles (two way) 12484 12374 8179 5474 1564 626
    Annual CO2e Emissions (MT) 2.971 2.693 2.178 1.391 0.458 0.078
    Number of employees 1928 310 359 74 47 143

    The table and graph here show how estimated commute miles and greenhouse gas emissions from commuting vary by the frequency of telework, as well as how many OPM employees fell into each frequency category. It is evident that as telework frequency increases, there is a steady and linear decline in both commute miles and emissions due to commuting. For example, a non-teleworker that does not telework on average drives about 12,000 miles a year to and from work. For a teleworker that works from home 3 days a week, that number drops to about 5,500 miles. While it is not quantified here, this savings would undoubtedly result in savings in time spent on the road, wear and tear on one’s vehicle, and money spent on gasoline. A similar decline is seen for emissions related to commuting. A change in behavior from not teleworking to teleworking 3 days per week decreased emissions from about 3 MT to 1.4 MT CO2e, or about in half.

    Concluding Remarks

    It is important to remember that this analysis is meant to be a simple estimate of the amount employees are saving in commute miles, emissions, gasoline, and fuel costs. It reflects a sample of OPM employees, not the entire agency. It may also be the case that some teleworkers would use public transportation rather than their own cars if they were not able to telework, a factor that is not included in the analysis. There are other factors to consider as well, such as increased short trips during the day while teleworking. The goal here was to collaborate within OPM to use a rich source of data to produce a rough estimate of how much employees may have saved through telework.

    In sum, these estimates give us a sense of the magnitude of savings that may be achieved through telework. This analysis was fairly simple to produce and provides an example of a potentially useful tool for developing return on investment calculation for telework, an important element in building the business case for telework and promoting agency programs.

    OPM’s Federal Telework Team would like to thank Morris Thompson, OPM, Dee Siegel, OPM, and Jennifer Hazelman, Manager of Carbon Footprint, GSA for their assistance with this analysis.