Carbon Balance Program Resource Information

The carbon offsets for PSE’s Carbon Balance Program are sourced from a methane capture project at a dairy farm located in Outlook, WA, called George DeRuyter and Sons Dairy.

How can a dairy farm supply carbon offsets?

Manure on dairy farms produces methane as it decomposes. Methane traps 21 times as much heat as carbon dioxide and is a potent greenhouse gas. However, if the methane is captured, it can be destroyed and even turned into energy. Dairy farms like George DeRuyter and Sons utilize a biodigester to facilitate this process.

What is a biodigester?

A biodigester is a system that captures waste products, such as manure, and turns them into energy and other useful products, while reducing greenhouse gases.

Since 2006, George DeRuyter and Sons Dairy has used a biodigester to process the manure of about 4,000 milking cows. The methane from the manure is captured and used to produce up to 1.2 megawatts of electricity—enough to power approximately 700 American homes per year.


How does a biodigester work?

  1. Manure is transported to the digester
  2. The digester is free of oxygen (anaerobic), and as the manure decomposes, methane is generated and captured
  3. Methane is destroyed in a reciprocating engine connected to an electric generator or flare

Sign Up for PSE's Carbon Balance Program 

You can enroll your home or enroll your business in the PSE Green Power Carbon Balance Program right now online or by calling a PSE Energy Advisor at 1-800-562-1482, Monday through Friday 8 a.m. to 5 p.m.