Concentration of CO2 in the Atmosphere

Cow Power, Renewable Energy from Manure


Anna Chaffee

As a society, maintaining our current standard of living necessitates large-scale farming. This comes at a cost however, as the industrial agriculture system is a major contributor to global warming largely through greenhouse-gas (GHG) emissions, such as methane. As a result, the current agricultural system has much progress to be made in terms of sustainability.

The United States Environmental Protection Agency (EPA) found that livestock represents nine percent of all GHG emissions in the United States1. The world’s 1.3 billion cattle population is responsible for one fourth of the world’s methane levels, which have doubled over the past three centuries2. With the amount of food required to sustain the world’s population, it’s inevitable that the cattle population will continue increasing. Therefore, mitigation efforts to decrease methane emissions from livestock should move towards managing the manure produced from cattle.

Thinking about using manure as an energy source may cause some people to shudder. However, I think the idea of capturing methane from manure and using it as electricity is brilliant. Methane losses from manure are responsible for 41 percent of total agricultural methane emissions for most countries around the world3. By converting this methane into electricity through anaerobic digesters, the amount of methane emissions to the atmosphere would decrease drastically.

Anaerobic digesters consist of a large covered concrete tank that is installed in the ground with heating pipes to heat the manure inside the digester. The heat promotes the bacterial decomposition of manure, creating methane. An engine-generator will also be installed that is fueled by the methane captured from the digester. The digested liquid waste left over in the concrete tank can be used as natural fertilizer on crop fields.

Biogas holder and flare. Image: Wikipedia

Vermont has been leading the way in using manure as an electricity source for over a decade. Green Mountain Power (GMP), which is used by nearly three-quarters of Vermonters for electricity, offers a Cow Power program using anaerobic digesters that provides renewable energy while supporting local farmers. The profits earned from Cow Power are given back to farmers as incentives to be involved with the program.

Cow Power currently powers more than 3,000 homes and businesses, including Killington Resort and other large companies. The residents using Cow Power have reduced the amount of GHG emissions equivalent to taking 9,000 cars off of the road each year, which would have burned 5.3 million gallons of gas.

Farmers coupling with the GMP Cow Power program also help reduce agricultural runoff going into Lake Champlain. On hot days in the summer, blue-green algae blooms take over our beautiful lake, mainly due to the excess nutrients in the water from run off. If more manure is going to anaerobic digesters, it will prevent harmful run off from dirtying our waters.

Overall, I believe that reducing the methane emissions produced from agriculture will help mitigate the effects of climate change while benefiting farmers. Any Vermonter using GMP has the possibility of using renewable energy sources. In the future, the Cow Power program could be opened up to any Vermonter, not just those using GMP. Additionally, other states around the country could take Vermont’s lead and start similar programs for their residents. Let’s work together to save our planet!

Anna Chaffee is a Vermont native, currently living in Burlington. She is a senior at the University of Vermont and will be graduating in the spring of 2020 with a Bachelor of Science degree in Environmental Science. Protecting our environment is Chaffee’s passion and why she hopes more people will learn about methane digesters and consider implementing them on their farms.

1 EPA (2017). Sources of Greenhouse Gas Emissions. Accessed on 12/5/2017. Available at:

2 Lassey, K.R (2008). Livestock methane emission and its perspective in the global methane cycle.

3 Haeussermann, A., Hartung, E., Gallmann, E., Jungbluth, T (2006). Influence of season,

ventilation strategy, and slurry removal on methane emissions from pig houses. Agric. Ecosyst. Environ. 112, 115–121. Accessed on 12/5/2017.

4Levine, Sandy (2013). Cow Power, the Vermont brand electricity. Accessed on 2/20/2020. Available at:

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