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Assumptions and Methodologies for Processing Data In FleetDASH
Developed by the U.S. Department of Energy (DOE) Federal Energy Management Program (FEMP), the Fleet Sustainability Dashboard, or FleetDASH, supports the U.S. General Services Administration (GSA) leased portion of Federal fleets using GSA Reports Carryout data sets.
The FleetDASH tool uses the following information, processing methods, and definitions:
- Data Sources
- Missed Opportunities
- Fuel Use by Type
- Monthly Fuel Consumption
- Data Processing
- Data Quality
FleetDASH's primary data set is the Transactional by Vehicle report within the Fuel Use Reports section of the GSA Reports Carryout system. The Transactional by Vehicle report includes individual fuel transaction records that show each time a driver purchased fuel for a GSA leased vehicle with the fuel card associated with that vehicle.
FleetDASH uses the following information from the fuel transaction records:
- The fuel type of the vehicle for which the fuel was purchased
- The type of fuel purchased
- The purchase date of the fuel
- The station name, address, city, state, and ZIP code of the purchase location
- The quantity of fuel purchased in the natural units of the fuel
- The billed office address code (BOAC) of the organization to which the vehicle is assigned.
Data for a given month will be available on the FleetDASH website by the 28th day of the following month. For example, data for January will be pulled from the Reports Carryout system on February 15 and will be available on FleetDASH by February 28. The FleetDASH team pulls data in accordance with the Reports Carryout schedule for loading bulk transaction data from Defense Logistics Agency (DLA) Energy (formerly the Defense Energy Support Center, or DESC), which occurs between the 10th and 15th days of each month.
Missed opportunities are defined as instances where dual-fuel or flex-fuel vehicles capable of operating on an alternative fuel are fueled with petroleum at a location where the appropriate alternative fuel is available.
- An alternative fuel is determined to be available if a station known to sell the fuel is publicly accessible, accepts the Wright Express (WEX) card used by GSA leased vehicles, and is within 5 miles of the station where petroleum was purchased.
- Alternative fuel station locations are determined by the Alternative Fueling Station Locator database available at the Alternative Fuels and Advanced Vehicles Data Center (AFDC).
Fuel Use by Type
The Fuel Use by Type chart shows the total amount of fuel used by type during the current fiscal year (FY) to date. The grey shades in the graph represent petroleum fuel use and include gasoline and diesel. The outer ring shows the quantity of gasoline and diesel use, as well as the total quantity of petroleum fuel that could have been replaced by an alternative fuel (labeled "Missed Opps" in the graph and shown in red). See the Missed Opportunities section.
The green shades in the graph represent alternative fuel use. The outer ring shows the quantity of alternative fuel use and includes the following types of alternative fuel: E85 ethanol, biodiesel (B20), compressed natural gas (CNG), liquefied natural gas (LNG), liquefied petroleum gas (LPG or propane), and electricity.
All fuel quantities shown in FleetDASH are in units of gasoline gallon equivalents (GGEs), which is the number of gallons of the fuel in question that contain the same amount of energy as one gallon of gasoline. For example, because E85 contains less energy in a gallon than gasoline, a fuel purchase of 1 gallon of E85 is represented in FleetDASH as a purchase of .7 GGEs of E85. See the Data Processing section for additional details.
Monthly Total Fuel Consumption
The Monthly Total Fuel Consumption chart shows the quantity of fuel consumed by month, comparing each month in the current fiscal year (FY) with the same month in the previous year. The graph is broken up by fuel type. The grey shades represent petroleum fuel use and include gasoline and diesel as well as the total quantity of petroleum fuel that could have been replaced by an alternative fuel (labeled "Missed Opps" in the graph and shown in red). See the Missed Opportunities section.
The green shades represent alternative fuel use and include the following types of alternative fuel: E85 ethanol, biodiesel (B20), compressed natural gas (CNG), liquefied natural gas (LNG), liquefied petroleum gas (LPG or propane), and electricity.
This section describes how raw data from the Transactional by Vehicle report is organized for presentation in the dashboard:
- Assign transaction to an organization—Each fuel transaction record is assigned to an organization based on the BOAC of the record.
- BOAC-to-organization mapping is determined by Federal agency fleet executive management.
- Records with unassigned BOACs are excluded from the dashboard until the BOAC assignment is made.
- Records with assigned BOACs that are excluded from reporting by agency fleet executive management are excluded from the dashboard.
- Calculate fuel quantity units—The natural units of the fuel transaction are converted to gasoline gallon equivalents (GGE).
- The conversion factors for each fuel type can be found in Table 5-2 of the official Guidance for Federal Agencies on E.O. 13514 Section 12; Federal Fleet Management.
- Calculate greenhouse gas emissions—Greenhouse gas (GHG) emissions are calculated in metric tons of CO2 equivalents (MT CO2e) by applying GHG emissions factors to the quantity of fuel purchased for each fuel transaction record.
- GHG emissions factors for each fuel type can be found in appendices D & E the Comprehensive Federal Fleet Management Handbook.
- GHG emissions factors are consistent with the White House Council on Environmental Quality (CEQ) Guidance for Federal Greenhouse Gas Accounting and Inventories.
- Locate fuel station—The station location for each transaction is assigned a specific latitude and longitude according to the criteria described below.
- Caveat: Incomplete or erroneous address information in fuel transaction records can lead to inexact geo-locations.
- Identify missed fueling opportunities according the criteria described in the Missed Opportunities section.
Geocoding is the process of translating a physical address to a latitude and longitude. FleetDASH uses geocoding to determine the locations of fueling transactions and vehicle garages using a Google geocoding service. That service provides the following accuracy levels (premise is the most accurate level):
- Postal Code
When geocoding addresses, FleetDASH first checks for a geocode with an accuracy at the address level or better. Due to uncertainty regarding the actual placement of a location, FleetDASH defaults to the postal code accuracy level when geocoding results are returned at the intersection or street levels. Approximately 16% of all stations are currently geocoded at the postal code level. Stations that are geocoded as locality, region, unknown, and NULL are not assigned a latitude and longitude and are not accounted for in geographic analysis; however, fuel use from these stations is accounted for in the fuel consumption summaries. Approximately 0.4% of all stations fall into this category.
The systems that log fuel purchase transaction data are automated rather than hand-entered, which means that the data quality in general is robust. However, there are a number of issues that can affect data quality.
Miscoded Fuel Transactions
In some instances, GSA's transaction data shows an unexpected fuel purchased for a particular type of vehicle; for example, B20 purchased for an E85-capable vehicle, or diesel purchased for a gasoline vehicle. This may cause fuel purchases to be improperly assigned. Currently, these transactions are accounted for in the fuel use summaries according to the fuel type purchased, as opposed to re-categorizing the fuel purchased based on the vehicle type.
FEMP has also received feedback from a number of Federal fleets that alternative fuel purchases are not correctly recorded in transaction records; for example, E85 was purchased for a flex-fuel vehicle, but the transaction is recorded as a gasoline purchase. The FleetDASH team is investigating the extent of this problem and exploring ways to correct it. Information on incorrectly coded fuel transactions should be sent to Ryan Daley at the National Renewable Energy Laboratory (NREL).
Sporadic Reporting of Fuel Purchase Data
Fuel purchases at Federal fueling facilities may show up in a single month, throwing off monthly trends, or may not show up at all, resulting in an under-reporting of fuel use. The FleetDASH teams is investigating the extent of this problem and exploring ways to correct it.
In general, when looking at a larger dataset (as of April 2012, FleetDASH contained nearly 1.6 million transactions), these problems are less significant. In smaller datasets (e.g., fleets with fewer vehicles), these data quality issues can affect monthly trends. The FleetDASH development team is working to understand the scope of these problems and correct them to the extent possible.
Unknown Fuel Transaction Location
In some cases FleetDASH cannot accurately determine the location of a fuel transaction. This can result in a missed opportunity being shown where none exists.
Occasionally an alternative fueling station may close or stop offering the alternative fuel after a missed opportunity was recorded. In that case, clicking on the “Alternate Station” link on the Missed Opportunities by Vehicle page will indicate that there is no alternative fuel available within a 5-mile radius.
Incorrect Vehicle Information
Examples of incorrect vehicle information include a gasoline vehicle marked as a flex-fuel vehicle, or an incorrect BOAC or tag number associated with a transaction. These problems can cause vehicles to appear in the wrong organization, or missed opportunities to be reported for vehicles that are not flex-fuel vehicles.