Menu Home

Measuring Greenhouse Gas Emissions at Port of Seattle

COVID-19 and travel at SEA Airport More Information

About the Port's Greenhouse Gas Emissions Inventories

The Port conducts two separate greenhouse gas (GHG) emissions inventories: one for GHG emissions associated with the Seattle-Tacoma International Airport (SEA Airport) and the other for GHG emissions from its maritime-related sources, which include the Port's Maritime and Economic Development Divisions' lines of business separate from SEA Airport. Both Port inventories follow the GHG Protocol Corporate Accounting and Reporting Standard to estimate Scope 1, Scope 2, and Scope 3 emissions, which represent sources directly and indirectly controlled or under some degree of Port influence. Inventories track progress toward the Port's Century Agenda GHG reduction targets set by the Port of Seattle Commission in 2017 to align with the Paris Climate Agreement. The SEA Airport GHG Emissions Inventory is verified by the Airport Carbon Accreditation Program. The Port's Maritime GHG Inventory is newer and not yet verified, but the Port may seek verification for future maritime inventories. 

Port of Seattle conducts GHG emissions inventories annually for the previous calendar year. Starting with the year 2019, historical and prior year inventory results will be publicly posted online each year as soon as the inventory process is complete. The Port is committed to data accuracy and transparency and the inventories represent a best estimate of emissions sources. As new information or inventory best practices become available, the Port may update historical data or inventory methods to better reflect its sources and their contributions. 

Port of Seattle Century Agenda GHG Targets
Scopes 1 and 2 Scope 3
Port-controlled and Port indirect emissions Emissions the Port has influence over but not direct control
  • 15 percent below 2005 levels by 2020
  • 50 percent below 2005 levels by 2030
  • Carbon neutral OR carbon negative by 2050
  • 50 percent below 2007 levels by 2030
  • 80 percent below 2007 levels by 2050

Port-Wide Greenhouse Gas Emissions

Scope 1 and 2 GHG Emissions

Scope 1 and 2 emissions include direct emissions from sources under the Port's control (scope 1) or indirect emissions produced to generate the electricity used by the Port (scope 2). The Port conducts inventories for Scope 1 and 2 emissions annually. 

Scope 1 Sources Scope 2 Sources
  • Fossil fuel used in Port-owned vehicles and equipment, and employee vehicles for Port business
  • Fossil natural gas used in Port-owned buildings, and not metered and sold separately to tenants. 
  • Purchased electricity used by the Port of Seattle in Port-owned buildings, and not metered and sold to tenants
  • Purchased steam used in Port-owned buildings, and not metered and sold to tenants

Graph demonstrating the trajectory of GHG emissions reductions from 2019 to 2050

In October of 2020, SEA Airport became the first airport in the country to purchase thermal renewable natural gas (RNG) derived from waste. This decision to use RNG to heat SEA Airport and power the Airport's bus fleet will significantly reduce the Port's Scope 1 and 2 GHG emissions, allowing the Port to meet its 2030 goal 10 years early. The impact of RNG on the Port's GHG emissions will be represented in the 2020 inventory results - available later this year on this webpage. 

Port of Seattle Scope 1 and 2 GHG Emissions Data
Airplane icon SEA Airport Scope 1 and 2 Emissions Inventory Data (2019)
Sailboat icon Port of Seattle Maritime Scope 1 and 2 Emissions Inventory Data (2019)

 

Scope 3 GHG Emissions

Scope 3 GHG emissions are indirect sources of emissions that are a consequence of the Port's activity but are owned or controlled by another entity. Scope 3 emissions sources include energy used by Port tenants, airplanes, ground transportation to and from the airport, cruise ships and other ocean-going vessels, cargo-handling equipment, rail locomotives, waste transport and disposal, employee business travel by air, and even Port employees commuting to and from work. 

Port of Seattle Scope 3 GHG Emissions Data
Airplane icon SEA Airport Scope 3 Emissions Inventory Data (Coming Soon!)
Sailboat icon Port of Seattle Maritime Scope 3 Emissions Inventory Data*

*Note: Data on GHG emissions from maritime supply chain (ocean-going vessels, commercial harbor vessels, recreational vessels, locomotives, cargo-handling equipment, cruise buses on terminals) comes from the Puget Sound Maritime Air Emissions Inventory. Completion of this inventory occurs every 5 years and is complex as the Port does not own or manage the vessels and equipment. The 2019 Maritime Scope 3 Emissions data uses 2016 GHG emissions levels for maritime supply chain sources because 2016 is the most recent year that data from these sources is available. The next Puget Sound Maritime Air Emissions Inventory will be complete for year 2021. 

Related to Measuring Greenhouse Gas Emissions at Port of Seattle

Back to Top