Environmental Impact
Because of the nature of our business, developing and maintaining an accurate greenhouse gas (GHG) emissions inventory and complying with regulations for reporting these emissions is a priority.
We do not rely solely on emissions reductions as an indicator of our environmental performance. We also focus on improving our pipeline-integrity and pipeline-optimization programs, remediation during pipeline construction and our conservation efforts.
Greenhouse Gas Emissions
The Environmental Protection Agency’s (EPA) Mandatory Greenhouse Gas Reporting rule, released in October 2009, requires annual GHG emissions reporting. Prior to this rule, we reported our annual GHG emissions voluntarily using internally determined criteria.
The main difference between our previously calculated numbers and the new, required reporting structure is that we are now required to report the GHG equivalents of the natural gas and natural gas liquids (NGLs) delivered to our customers. Because of the difficulty of calculating individual customer emissions, those emissions are attributed to the company that delivers the product. For 2010, our GHG emissions estimated using the new reporting criteria were about 66.5 million metric tons of carbon dioxide equivalents (CO2e).*
Our previous emissions estimates included emissions calculations from the majority of our facilities. The new reporting rule requires organizations to report emissions only from facilities that emit at or above the 25,000 metric tons of CO2e per-year threshold set by the EPA. Based on threshold levels in 2010, we reported combustion emissions from 11 facilities totaling approximately 1.1 million metric tons of carbon dioxide equivalents.
We also continue to focus on maintaining a low rate of lost-and-unaccounted-for natural gas, which continues to register less than 1 percent of total throughput for all of our business operations.
Greenhouse Gas Emissions (2010)
The graph below represents our total 2010 emissions reported as CO2e to the EPA per the new Greenhouse Gas Reporting Rule criteria. The amount supplied to our customers is the amount of natural gas and natural gas liquids that we transported or delivered to other customers. This number excludes natural gas supplied to customers who emit at or above the EPA’s reporting threshold and are required to report on their own. The facility-direct emissions represent emissions directly attributable to us – burned and released as a result of our operations. We are also required to report our carbon dioxide emissions injected underground for purposes such as geologic sequestration. This number is not included on the graph below because it represents less than 0.05 percent of our total emissions reported.
Breakdown by Business Unit of Emissions Supplied to Customers
The Greenhouse Gas Reporting Rule for the first time required reporting of the natural gas and natural gas liquids we supplied to customers. The majority came from our natural gas liquids business segment as a result of NGLs delivered to industrial customers. Although reported as CO2e, a large portion of the natural gas liquids are used as raw materials for the petrochemical industry to produce plastics and other products and are not directly combusted. The 20 percent of CO2e that came from our natural gas distribution segment is attributable to the residential and business customers of our three natural gas distribution companies.
Breakdown by Business Unit of Our Facility-direct Emissions
Facility-direct emissions represent our emissions, burned and released as a result of our operations. Eleven of our facilities were required to report emissions because they emit at the threshold set by the EPA, 25,000 metric tons of CO2e per year. Our natural gas distribution and natural gas pipelines segments did not have any facilities with emissions above the reporting threshold.
* Carbon Dioxide Equivalent (CO2e) is a metric measure used to compare the emissions from various greenhouse gases based on their global warming potential. It is determined by multiplying the tons of a specific greenhouse gas by its associated global warming potential.