Katherine Hanks, Peter Elmore, Meaghan Weber, James Dean
The Clean Energy Fund is always looking for new ideas for generating renewable energy at the University of Vermont. Our proposal consists the construction of an anaerobic digestion system that will take the manure of Vermont Dairy Farm cows and turn it into electricity and heat for the barn. CowPower is a anaerobic digestion system and program that will allow for the CREAM barn to run on its own electricity and would be very cost effective after several years of producing its own needed utilities.
Introduction & Background
An anaerobic digestion system is a mechanism that converts a portion of the organic carbon in manure to methane and carbon dioxide. This anaerobic digestion produces a renewable energy source called biogas, reduction of greenhouse gas emissions, and a pathogen reduction in manure. Biogas can be used for heat and energy production by a cogeneration system.Beyond that, the anaerobic digestion system produces effluent liquid that is the manure that is leaving the digester. Effluent liquid that leaves the digester with about half the carbon that regular manure contains. This effluent liquid when processed by the anaerobic digestion system has a significantly reduced odor and can then be spread on agricultural land to fertilize crops for a less foul, but efficient manure. UVM currently has around 65 cows at the CREAM dairy barn. On average one cow can produce 30 gallons of manure daily. This means that UVM’s barn could produce around 1,950 gallons of manure every day, which depending on the digestion system could produce enough energy to support the barn.
Methodology & Timeframe
The construction of a plug flow anaerobic digester is a simple design. There is an underground concrete housing with three rectangular chambers. The subterrenan digester is covered with flexible geosynthetic cover to collect the methane gas released from the chamber. Due to the simplistic nature of the system’s design, construction usually takes about two months to complete. Despite a short time frame for construction, the financial organization to build and integrate this system into the UVM energy grid would take about two and a half years of the Clean Energy Fund’s money to cover the total construction cost of close to $500,000. After the digester is built it will take anywhere from 4-8 years for to recover from initial investment and begin saving money for the school. One process that is optional but would save money for installing an anaerobic digester would be the application process to receive government grants and subsidy money to assist with the financial side of the operation. The added time of this process could last anywhere from a few weeks to a few months.
Benefits & Results
There are numerous benefits to constructing an anaerobic digester. Because manure is a clean renewable energy source, its construction would be one step towards UVM could make to help the state reach for its 2050 goal of 90% renewables. Not only is the system renewable, but provides an outlet to make waste useful, instead of increasing the amount of methane released into the atmosphere. We would use what is usually waste, and turning it into a surprisingly efficient form of energy. The cow manure provides a lot of energy per unit, and that energy can be co-produced to provide both heat and electricity, especially important during cold Vermont winters. All of this clean, renewable energy makes UVM available to receive carbon credits from the government, providing a financial reward for safeguarding our environment with clean energy.
The budget is comprised of three main categories: generator system, digester system, and operation & maintenance. Operation and maintenance costs are arbitrary because student internship and projects related to the anaerobic digestive system could subtract from the total estimated cost. According to the United States Department of Agriculture it should take between four and eight years for this project to become cost effective. Here are the estimates that we have on this project but all are subject to change.
Generator System $200,000
Digester System $300,000
Operation and Maintenance $14,804
Total Cost $514,804
With the rising cost of energy and greenhouse gases occurring in the atmosphere, student organizations and engagement have been taking these environmental issues into their own hands. Utilizing the school's resources to provide a fraction of our own electricity provides a platform for undergraduate and graduate students at UVM to learn, engage and act on climate change issues. Through the CowPower program at the Paul Miller Research Complex, students will have these opportunities through an internship program. The student internship will act as maintenance to the facility and creates opportunities for students to experience a job relative to their area of study.
Justification for use of student-supported, CEF Funds
The livestock sector has emerged as one of the most significant contributors to local and global environmental problems. Methane is produced during decomposition of organic material in livestock manure management systems. Liquid manure management, such as holding tanks that more most commonly dairy farms, can cause significant methane production. Methane gas is one of the most potent and influential gases and traps 25 times more heat per mass unit than carbon dioxide. The CowPower initiative will allow for the UVM community to create an alternative to these environmentally destructive waste management systems while making the Paul Miller Research Complex self sustaining through student activities.
Being a research university, UVM has an opportunity to experiment with alternative technology that has great student engagement potential. Internships and hands-on jobs at the Paul Miller Research Complex can have positive impacts on student involvement in agriculture and climate change issues. The CowPower program is an excellent way for students to learn about and work with alternative energy as Vermont moves towards 90 percent renewable resources by 2050.