The Northwest (NW) Iowa Renewable Natural Gas (RNG) Plant produces RNG
from biogas generated across three dairy farm sites in Iowa, where manure is
used as a locally available feedstock. The project operates as a stand-alone
system, upgrading dairy-derived biogas to pipeline-quality RNG.

Merrick provided Front End Loading (FEL)-2 and 3 engineering and design, detailed engineering, and total project integration for the three dairy sites and
one centralized biogas upgrading facility. Instead of completing the full manure-to-RNG process at each location, the project uses a “satellite” approach: manure processing, anaerobic digestion, and biogas conditioning occur at each dairy, while biogas is transported via pipeline to a single common upgrading site. This configuration reduces land use, limits redundant infrastructure, and allows
each site to be customized to existing dairy operations.

The project received U.S. Environmental Protection Agency registration approval,
enabling participation in the Renewable Fuel Standard and California’s Low
Carbon Fuel Standard programs. Beyond energy production, the project captures
methane emissions that would otherwise be released from open-air manure
lagoons, returns digestate to dairy owners for reuse, and establishes a scalable
model for future multi-site agricultural RNG developments.