Grantee Research Project Results
Final Report: Environmental and Economic Impact Analysis of Manure Digester Biogas-Powered Fuel Cells for the Agricultural Sector
EPA Grant Number: SU833156Title: Environmental and Economic Impact Analysis of Manure Digester Biogas-Powered Fuel Cells for the Agricultural Sector
Investigators: Sammes, Nigel M. , Serincan, Mustafa Fazil , Lassman, Alex , Mohammadi, Alidad , Davis, Chase , Pusz, Jakub , Sayers, Jennifer , Kukielka, Jessica , Gherard, Katherine , Murphy, Melanie
Institution: University of Connecticut
EPA Project Officer: Page, Angela
Phase: I
Project Period: September 30, 2006 through May 30, 2007
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2006) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Air Quality , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities
Objective:
The goals of this project aimed to build upon the known applications of anaerobic manure digesters as a new renewable energy source. In applying fuel cell technology, this project supports the feasibility and economic incentives for generating a significant source of energy for an agricultural production facility while reducing harmful particulates and greenhouse gas emissions. This project was composed of two major research objectives. The first purpose was to demonstrate the potential of operating SOFC on a methane-rich biogas produced from anaerobic digesters in the agricultural industry. To do so, the team needed to investigate whether the SOFCs could operate properly, and with enough efficient power, on methane. This ratio of energy conversion potential was compared to applications on pure-hydrogen to gauge the cells’ overall performance.
The second purpose of this study was to assess the economic feasibility of SOFC applications to an Anaerobic Digester (AD) waste management system. The investigators utilized a substantial database of information and historical data collected by the New York State Energy Research and Development Authority (NYSERDA) and Cornell’s CowPower program – a waste management research colloquium for dairy farm assessment in New York State. The data obtained from this taskforce included sample data on farm capacity and average herd sizes, the expected biogas output per cow, biogas characteristics and variability, as well as important information comparing average farm electricity usage and output resulting from herd size and applied energy conversion systems, respectively. The challenge, in real world applications, has been to find a fuel-flexible fuel cell system that could provide all of these benefits, but still be cost-effective in its purchase, installation, and adaptation to existing capital-machinery in the AD facility.
Summary/Accomplishments (Outputs/Outcomes):
An anode supported tubular solid oxide fuel cells have been successfully fabricated basing on the technology developed and published by two student group members [1]. The cell in this design was sealed outside of a furnace in a cold zone using a brass fitting and high-temperature silicone gasket. The cell and the seal proved to be gas-tight, which was verified by a very high open circuit voltage of 1.115V measured at 800°C on humidified hydrogen. After a stable performance of the cell was reached, a humidifier was set to 80°C and methane was fed to the cell.
Another cell was tested using a computer-controlled SOFC test station by Scribner Associates. The ends of the cell were glued using ceramic glue into two alumina tubes. The complete cell, with two long alumina tubes glued to it, was inserted into the furnace and slowly heated up. After 145 hours of cell operation on hydrogen, methane – bubbled through the humidifier (set at 80°C) – was provided to the cell. A sudden decrease in power density was observed, which corresponds to the lower energy content of methane comparing to hydrogen. Even thought the cell was operated at the constant 0.8 V condition, a “jumpy” power response was recorded. The amplitude of the “jumps” was fairly uniform, with a slight tendency of decrease. The reason was identified as a part of a non-insulated fuel line inside of the SOFC test station, which resulted in water condensation. Water inside of “U” shaped piece of the fuel line worked as a cork being pushed up and down by the fuel stream.
Figure 1. Continuous operation of SOFC on hydrogen (blue line) and methane+steam (green line).
The economic feasibility assessment was completed by comparing the Net Present Values of two conventional energy conversion systems to the NPV of SOFC applications in small (500head herd size) and large (1000-head herd size) dairy facilities. These conventional technologies include internal combustion diesel engine generators and microturbine applications that provide significant cogeneration of cooling, heating, and power (CHP). We assumed a homogeneous application of each of the three systems, to a dairy farm of small (and large) size herds, a plug-flow anaerobic digester, and infrastructure capabilities for electricity output to grid supplier.
Conclusions:
Economic and scientific study showed that solid oxide fuel cell could be successfully utilized in the agricultural sector; namely, on various sized-dairy facilities utilizing anaerobic digesters. Scientific study performed by the group members proved their capabilities of fabrication solid oxide fuel cell that would run on methane-rich gas. Therefore, the concept of SOFC run on methane, even though extremely difficult, is possible.
What we have uncovered through economic analysis are two exciting outcomes. First, there is evidence to suggest that, while SOFC applications may not be the most economically efficient method of energy conversion for a small scale dairy facility, Secondly, SOFC applications to large-herd farms can be a highly desirable and beneficial option for the facility, with a payback period of only 2 to 3 years. Overall, SOFCs are shown to have a strong potential for increasing farm profitability.
Proposed Phase II Objectives and Strategies
The goals for the Phase II of the engineering part of the project are as following:
- Understand and publish the solution of running a tubular SOFC on methane-rich gas
- Comparison of performance of small versus regular-size cells run on methane
- Build a small demonstration system, which would run to represent real-life application.
- Educate a number of students on how to operate and evaluate fuel cell
- Present the operation of the demonstration to local farming community and explain the benefits of biogas fueled SOFC.
A successful SOFC biogas-fueled system is characterized by a zero carbon deposition, high reformation efficiency and resistance to thermal shocking. Thus, all the cells will be investigated to verify if they fulfill those criteria.
Success in the economic assessment will be defined by:
- Completing a sensitivity analysis of the Phase I scenarios as a result of electricity rate changes for purchase and sale. A cross-sample comparison between each energy conversion system to define the upper and lower bounds of NPV for each system.
- Complete an initial non-market valuation of the expected net benefits of SOFC applications on a small and large dairy farm. Encourage students to perform non-market valuation studies and evaluations for any area related to SOFC impacts on the environment and society.
- Development of a general regression model to test the cross-price substitutability among these emerging technologies, using fuel cells, microturbines, and solar powered generators as sample technologies to establish and test the model.
- Complete general inferences on the effect of competitive and emerging alternative energy technologies on individual technology benefits.
Reference:
[1] Pusz, J., Mohammadi, A., & Sammes, N. M. (2006). Fabrication and performance of anode-supported micro-tubular solid oxide fuel cells. Journal of Fuel Cell Science and Technology, 3(4), 482-486.
Supplemental Keywords:
methane, biogas, digester, manure, greenhouse gas, solid oxide, fuel cell, impact analysis,, RFA, Scientific Discipline, TREATMENT/CONTROL, Sustainable Industry/Business, POLLUTION PREVENTION, Sustainable Environment, Energy, Environmental Chemistry, Technology, Technology for Sustainable Environment, Economics, Environmental Engineering, energy conservation, sustainable development, clean technologies, animal waste, biogas, fuel cell, agriculture, animal waste gasifier, emission reduction, bio-based energyThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.