Some Washington dairy cows are helping to heat homes by producing solid waste.
Every day at Vander Haak Dairy in Lynden, around 45-thousand gallons of manure flow into an underground vessel called an anaerobic digester. The digester captures methane and converts it into renewable energy, providing electricity for the farm, and area homes throughout the community.
In 2004, Steve Vander Haak was looking for a local sustainable solution to deal with the environmental challenge of combating global climate change. His digester, installed that same year, was the first of its kind in Washington and is leading renewable energy practices by reducing carbon emissions – more than 17,000 pounds every year.
“The digester works like the rumen (the largest stomach compartment) of a cow,” says Jon Van Nieuwenhuyzen, a third-generation manager at Werkhoven Dairy in Monroe.
Inside the underground digester, bacteria break down organic matter in the absence of oxygen. Animal waste, leftover unsellable produce from local grocery stores, wastewater, and even some surprising sources, such as grease traps from local restaurants. The matter transforms inside the digester, producing biogas, which is mostly made up of methane and carbon dioxide, and digestate, or leftover manure stripped of most of its methane and carbon dioxide.
Approximately three weeks later, the process is finally complete, and the biogas has been converted into electricity. The remaining digestate is used for animal bedding and fertilizer to grow crops to feed cows and farm families.
Werkhoven Dairy’s digester is part of a unique partnership with the Tulalip Indian Tribe. Their relationship grew from the mutual goal of preserving soil and rivers in the community. The digester generates enough electricity to power the farm and 300 homes in the area. Snohomish County PUD is in the process of building a new generator that will feed off the Werkhoven digester – doubling the output to create power for close to 600 homes.
The U.S. dairy industry is responsible for producing around 2% of all greenhouse gas emissions in the U.S. However, Washington dairy farmers are at the forefront knowing the decisions they make today will protect the land for subsequent generations to come and make dairy a key leader in the future of agriculture sustainability.
