Demeter Ag-Grid
Demeter Ag-Grid is Ag-Grid Energy’s first acquisition of an existing dairy farm digester project. This project has been operational for 15 years in Wisconsin and was originally built by Dane County to mitigate nutrients and protect the lakes in the surrounding area. The digester is centrally located and receives piped manure from three adjoining dairy farms. It originally produced 2 MW of electricity from manure- and food-waste-based biogas. In 2019, Brightmark acquired this facility and converted it to biogas-to-RNG (renewable natural gas).
Date Operational
Q1 2011
Project Partnership
Demeter Ag-Grid LLC, a special-purpose company, acquired this project as of July 1, 2026, to operate an anaerobic digester and renewable natural gas (RNG) system.
Funding
The facility requires upgrades, which will be funded through partner equity and debt.
Project Description
- MANURE — The digester will recycle over 160,000 gallons of manure daily from a total of 4 dairies: Maier Farms, Ripp’s Dairy Valley, Endres Dairy and Wagner Farms.
- ENERGY — Three on-site digesters generate 250 scfm of biogas which is then upgraded to renewable natural gas to produce ~100,000 MMBTUs of RNG annually.
- NUTRIENT REMOVAL – The project also removes phosphorus from post-digested manure via an extensive nutrient separation system, which supports the surrounding watershed area.
About the Farm and Farm Team
Our farm partners are: Maier Farms, Ripp’s Dairy Valley, Endres Dairy and Wagner Farms. The farms together have 4,500 milking cows, 450 dry cows and 650 heifers.
Impact on the Community and the Environment
The community benefits from odor reduction and significant phosphorus reduction to meet the area’s nutrient management requirements. Ag-Grid plans to further support the community targets and reduce the trucking of RNG by working with MG&E to implement direct pipeline access. Ag-Grid also plans to continue to utilize the project as an educational example and tool for the community.
The renewable natural gas from this project helps remove the equivalent of 18,000 vehicles from the road and reduces their greenhouse gas emissions.