July 2009, Automotive Fleet - Feature
Green Fleet: Benchmarking GHG Emissions
Metrics to measure fleet environmental progress must go beyond simply totaling the number of hybrid and alt-fuel vehicles. A new generation of metrics will track fleet greenhouse gas (GHG) reductions.
By Jason Mathers
As fleet efforts to reduce emissions grow more sophisticated and comprehensive, corresponding metrics to track progress must similarly evolve. Simply comparing a fleet's total of hybrid or alternatively fueled vehicles to benchmark success is no longer sufficient. A new generation of metrics must be developed around the ultimate goal of modern "greening" efforts: reducing greenhouse gas (GHG) emissions.
A free, online calculator created by Environmental Defense Fund (EDF) and NAFA Fleet Management Association enables any fleet with fuel consumption data to quickly find their emissions levels. With emissions data in hand, fleets can compare performance between internal units and external peers by indexing emissions along multiple characteristics, such as fleet size and mileage.
Use Comparable Units
As with all types of benchmarking, companies must use consistent and comparable units in tracking environmental performance. The most common unit used to measure GHG emissions is metric tons. For fleets seeking to compare environmental performance with peers, metric ton should be the base measure.
Clearly identifying the specific emissions tracked is also important; are fleets tracking only carbon dioxide or all vehicle greenhouse gases? While carbon dioxide is the easiest greenhouse gas to quantify, full GHG accounting from vehicles requires tracking emissions of methane, nitrous oxide, and refrigerants.
Fleets can utilize the environmental metrics outlined in this article to benchmark efforts internally and with peers. Given their multifaceted nature, fleets best pinpoint progress by tracking a series of metrics. For example, a fleet's total GHG emissions might be increasing because its vehicles are driving more miles, even if the vehicles themselves are more efficient. Each data point is critical to effectively managing fleet GHG emissions.
Metrics Just the Start
The metrics described are not comprehensive. Rather, they can help jumpstart a conversation within the fleet community about the best environmental metrics currently available to track progress. EDF encourages readers to share with us other metrics they have found useful, especially concerning how best to benchmark items such as idle time and routing efficiency.