Wanner Farms methane digester
How are the carbon offsets generated?
Anaerobic bacteria in the digester eat the cow manure, decomposing it and releasing methane gas as waste. The methane gas contained in the digester is then burned to heat water or generate electricity. Methane is a potent greenhouse gas, so burning it reduces the impact on the climate.
Carbon offsets are also created from the environmental attributes of each kWh of electricity produced by the farm. These kWhs displace kWhs from the grid, thereby reducing the amount of fossil fuel being burned and CO2 released.
Finally, carbon offsets are generated by using waste heat from the generator to boil water, because fuel oil burned onsite for water heating is greatly reduced. By reducing the amount of fuel oil combusted CO2 emissions are avoided.
What is done with the processed manure?
The processed manure solids that come out of the digester are sanitary, so they are used for bedding for the cows, saving the farm money. Digested manure liquids, which are essentially made odorless by the process, can be irrigated on nearby fields as natural fertilizer. Since this fertilizer is more easily absorbed by the plants and soil, the digester helps to reduce run off into local water ways, protecting aquatic ecosystems in the area. Other environmental benefits from reusing processed manure are reduced truck miles and material conservation benefits.
What’s the social or community value?
This project is helping the Wanner Family to ensure the viability of the farm well into the future. The Wanner Family’s decisions to install a digester are an investment in the future, as manure management and environmental sustainability become larger and larger issues for American family farms.
How is this project additional?
The sale of offsets represented a considerable portion of the entire project cost and allowed Wanner Farms to go ahead with the project. Without the sale of offsets, this project would not have gone forward.
Read more about ‘additional’ carbon offsets
Photo credit: NativeEnergy