By Blake Jackson
Animal waste, once burned as a source of heat in areas with limited firewood, is now helping farmers produce renewable energy through modern anaerobic digestion technology.
According to Christine Costello, associate professor of agricultural and biological engineering at Penn State’s College of Agricultural Sciences, anaerobic digesters can improve manure management while creating new revenue opportunities for farms.
Anaerobic digesters break down organic materials, such as manure, without oxygen, producing biogas and nutrient-rich digestate. The captured methane can generate electricity or renewable natural gas, reducing greenhouse gas emissions while replacing fossil fuels.
The remaining digestate serves as an organic fertilizer, and on dairy farms, the solid portion can also be used as animal bedding.
The U.S. Department of Agriculture reports that nearly 400 anaerobic digesters operate on large livestock farms nationwide, with most located on dairy farms. However, Costello believes the technology has far greater potential.
The U.S. Environmental Protection Agency estimates that more than 8,000 large dairy and hog farms could technically support biogas recovery systems.
Costello’s research also explores co-digestion, which combines manure with materials such as food waste, perennial grasses, and winter cover crops. This approach can increase renewable energy production, improve nutrient recycling, reduce emissions, and provide farmers with additional income through tipping fees for processing food waste.
As part of the Grass2Gas project, Penn State and Iowa State University researchers evaluated whether grasses and cover crops could economically support digester operations.
While incentives may still be needed to maximize profitability, the study highlighted valuable environmental benefits, including healthier soils and improved wildlife habitats.
To help producers evaluate whether anaerobic digestion is practical for their farms, Costello’s team created a decision-making tool that estimates energy production, greenhouse gas reductions, nutrient management, costs, and potential payback.
Costello believes anaerobic digestion will play an increasingly important role in expanding clean energy and sustainable agriculture across the United States.
Photo Credit: pexels-ou-kei
Categories: Pennsylvania, Livestock, Beef Cattle, Dairy Cattle