Drafter
Clerk 06/16/2026
title
AN ORDINANCE relating to the sale of environmental attributes held by the county; authorizing the county to enter into an agreement for the sale of environmental attributes related to biomethane produced at the South Treatment Plant to Karbone Energy LLC.
body
STATEMENT OF FACTS:
1. The wastewater treatment division of the department of natural resources and parks operates three regional wastewater treatment facilities, including the South Treatment Plant in Renton, Washington, which treats approximately twenty-eight billion gallons of wastewater each year.
2. Anaerobic digesters at the South Treatment Plant generate methane digester biogas as part of the wastewater and associated solid material treatment and purification processes.
3. Since 1988, the wastewater treatment division has been removing impurities from the methane biogas originating from the anaerobic digesters. Purified methane gas is also known as renewable natural gas, which is a direct substitute for geologic natural gas. The purified renewable natural gas that meets pipeline quality natural gas standards can be injected into the regional natural gas pipeline.
4. Renewable natural gas contains biomethane gas molecules that have an economic value similar to the value of geologic natural gas. In addition, the beneficial use of the wastewater biogas as a byproduct of the anaerobic digestion process provides significant greenhouse-gas reduction and other environmental benefits when compared to the consumption of fossil fuel-derived natural gas.
5. The environmental benefits, as an extension of the gas molecule energy content, are recognized as environmental attributes. Environmental attributes refer to renewable energy or other characteristics of a resource that are distinguished from a commodity and can have financial value related to both mandatory and voluntary environmental requirements and markets.
6. An example of a mandatory environmental attribute mar...
Click here for full text