Seattle-Tacoma International Airport Uses RNG for Thermal Reductions

The PDF version of the below case study is available here.

Washington’s Seattle-Tacoma International Airport (SEA) transports nearly 51 million passengers annually (prior to the coronavirus pandemic) with support from approximately 20,000 employees. As a functional body of the Port of Seattle, founded in 1911, sustainability has been a core focus for SEA and its counterparts— steadfast in their mission in “promoting economic opportunities and quality of life in the region by advancing trade, travel, commerce, and job creation in an equitable, accountable, and environmentally responsible manner.”

SEA’s Thermal Energy Challenge:

In 2012, the Port of Seattle set a goal to be the greenest, most energy-efficient port in North America—inclusive of objectives to target emission levels and energy use. SEA had already implemented renewable energy projects throughout their facilities, such as renewable diesel and renewable electricity, but their central mechanical plant was still consuming ~280,000 MMBTU of natural gas (annually) to heat their terminals. This figure accounts for roughly 80% of the airport’s and 75% of the Port of Seattle’s Scope 1 and 2 greenhouse gas (GHG) emissions. With sustainability targets in place, the airport knew they needed to reduce heat related emissions.

RNG Offers a Sustainable Feedstock Solution:

While SEA fueled their bus fleet with renewable natural gas (RNG) in 2014-2015, it took longer to determine how to best leverage RNG for thermal applications: especially as an airport and as a special purpose government. However, they already understood RNG’s emission reduction potential and knew it came with no change to their facilities or impact to their operations – removing any chance of disrupting their 24/7 operations. Knowing RNG’s significant contributions in promoting a clean energy economy, the airport supported bringing more biogas projects on-line.

The Resulting Emission Reductions from RNG:

After deliberation, SEA partnered with U.S. Gain to obtain RNG in October of 2020. This decision enabled the Port of Seattle to meet their 50% GHG emission reduction goals almost a decade early, through conversion from fossil natural gas to RNG. To appropriately track progress, SEA uses guidance from the IPCC for their biogenic emissions (zero fossil emissions) and the Greenhouse Gas Protocol to account for RNG emission reductions under Scope 1. This ensures their reporting abides with the Airport Carbon Accreditation guidance and third-party verification.

Next Steps in Renewable Thermal Adoption:

Demand for RNG as a low-carbon thermal solution continues to grow from sustainable organizations globally. When used in place of traditional thermal sources, RNG presents immediate emission reductions without upfront capital spend. Reach out to learn more about the impact RNG can have on your organizational sustainability goals. U.S. Gain will tailor a supply agreement based on your facilities’ current and future needs, inclusive of flexible terms you’ll appreciate.