Three Western Michigan farms have each signed supply agreements with Brightmark indicating their intent to provide the company with dairy manure from their herds that will serve as feedstock for new anaerobic digesters to be built on Beaver Creek Farm. The digesters will capture, extract, and clean the methane in the manure, then convert it into renewable natural gas (RNG) and inject it into a nearby gas pipeline.

“As a participating farm, we are excited to have Brightmark as a partner in anaerobic digestion of the manure from our cows. This investment will help local farms like ours continue to be environmentally friendly to our community and help us to exceed environmental regulations and responsibilities. We have always taken pride in being excellent stewards of our land, community, and industry.”

– Greg Stahl, owner of Den Dulk Dairy Farm

Project Benefits


Once the Castor project is fully operational in early 2022, it is anticipated to produce about 328,500 MMBtu of RNG each year, making this Brightmark’s largest RNG project to date.

Project Locations


  • Beaver Creek Farm: Coopersville, Ottawa County
  • Den Dulk Farm: Ravenna, Muskegon County
  • River Ridge Farm: Coopersville, Ottawa County

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