Biosystems and Agricultural Engineering Advancing Utilization of Manure Methane Digester Electrical Generation Philip Goodrich, R. Vance Morey, David Schmidt, Paul Burns, Matt Drewitz, Dennis Haubenschild, Amanda Bilek, David Nelson Richard Huelskamp

Advancing Utilization of Manure Methane Digester Funding for this project was recommended by the Legislative Commission on Minnesota Resources from the Minnesota Environment and Natural Resources Trust Fund ($204, 375)

Biosystems and Agricultural Engineering Background Have a well operating digester on an 800 cow dairy herd Biogas is being converted to electricity by 130 kW engine generator Digester is producing excess biogas

Biosystems and Agricultural Engineering Haubenschild Dairy Farm Energy Production Princeton, Minnesota Milk Production + Crop Production + Electrical Production + Future Hydrogen Production = Farm Income Diversification

Biosystems and Agricultural Engineering View of digester, barn and engine generator building at time of installation in 1999.

Digester Winter 2005

Biosystems and Agricultural Engineering

Plug-Flow Digester - A small “plug” of slurry is pumped into one end each day, causing a comparable amount to flow out of the other end into the storage basin in the background. Methane Digester: To breakdown organic matter in the absence of oxygen to biogas, which is primarily CH4/methane, CO2/carbon dioxide, H2S/hydrogen sulfide, and water vapor.

Biosystems and Agricultural Engineering Engine Generator set: Internal combustion engine with 135 kW 240 VAC electrical generator. Caterpiller 3406

Biosystems and Agricultural Engineering Biogas Production Used in Generator

Biosystems and Agricultural Engineering Objective Evaluate the feasibility of a fuel cell to convert biogas (methane) to electricity. Next step may be to produce hydrogen for farm use from biogas.

Biosystems and Agricultural Engineering Procedures to Achieve Objective Develop biogas gas cleanup system Install fuel cell on digester Test the fuel cell Monitor systems for energy, consumption and emissions

Biosystems and Agricultural Engineering Challenges Hydrogen sulfide removal –Initial concentration ~3000 ppm –Need concentration < 25 ppb Moisture removal –Need dry gas Carbon dioxide removal –Need concentration < 5 %

Biosystems and Agricultural Engineering Types of Fuel Cells Proton Exchange Membrane -Low temp Solid Oxide -High temperature Molten Carbonate -High Temperature

Biosystems and Agricultural Engineering Biogas

Biosystems and Agricultural Engineering A fuel cell is similar to a car battery in that it produces electricity through electrochemical reactions. A fuel cell produces electricity as long as the hydrogen fuel source and oxygen passes through it. Heat is also produced and can be utilized for space heating and hot water needs. Electricity conversion efficiency is around 25% The energy resources for hydrogen can be biogas, natural gas, propane, methanol, ethanol, and other hydrogen based liquids or gases.

Biosystems and Agricultural Engineering

The building at the left houses the 135 kW engine generator and the building on the right houses the fuel cell and instrumentation. One barn is to the right rear of the picture

Biosystems and Agricultural Engineering Fuel Cell: Uses hydrogen to generate electricity without combustion. Output is 5 kW at 120 VAC

Biosystems and Agricultural Engineering  Cost per kilowatt is very high. $10,000 -->20,000 per kW  Biogas must be cleaned up to strict specifications. Adds cost and complexity while consuming energy.  Fuel cell is an emerging technology. Comparing Electrical Generator Technologies Engine Generator System  Cost per kilowatt is low. $500 -->1000 per kW  Biogas can be used directly from the digester with no cleanup.  ICE is mature technology. Fuel Cell System

Biosystems and Agricultural Engineering  Greenhouse emissions and particulates are very low.  System is very quiet.  Few moving parts.  Cost of maintenance is unknown.  Fuel cell technology is continuously improving at a rapid rate. Comparing Electrical Generator Technologies Engine Generator System  Greenhouse emissions of CO2, SO2, CO and particulates are significant.  Noise level is very high and sound mitigation is necessary.  Many moving parts, most moving in a hot environment needing oil and cooling.  Maintenance is well known.  Technology is mature and changing slowly. Fuel Cell System

Biosystems and Agricultural Engineering Proton Exchange Membrane Fuel Cell (PEM) Advantages Could buy one from a vendor with experience Less expensive than others Made in lower capacity Disadvantages Low temperature water for heating Critical on gas quality Lots of gas cleanup needed

Biosystems and Agricultural Engineering Biogas Clean Up

Biosystems and Agricultural Engineering Biogas Clean Up

Biosystems and Agricultural Engineering Biogas Clean Up

Biosystems and Agricultural Engineering Biogas Clean Up

Biosystems and Agricultural Engineering Gemini Gas Monitor

Biosystems and Agricultural Engineering

Emissions from Haubenschild Generator Compared to Plug Power™ Proton Exchange Membrane (PEM) Fuel Cell  ( 800ppmv) 4.18 g/kWh  (2960ppmv) 25.5 g/kWh  (277ppmv) 3.34 g/kWh  (20460ppmv) 53 g/kWh  ( <1 ppmv) g/kWh  (<1 ppmv) <.0023 g/kWh  (<1 ppmv) <0.030 g/kWh  (1790 ppmv) 14.5 g/kWh Fuel Cell Engine Generator CO NOx SO X C X H Y

Biosystems and Agricultural Engineering Energy Production + Organic Fertilizer + Net Air Emissions = $nergy Income + $avings + Environment Impact Reduction

Biosystems and Agricultural Engineering Environmental and Economic Benefits 1) reduced reliance on fossil fuels 2) reduced odors and emissions 3) reduced soil and water pollution 4) supports rural economy

Biosystems and Agricultural Engineering Funding Funding for this project was recommended by the Legislative Commission on Minnesota Resources from the Minnesota Environment and Natural Resources Trust Fund ($204,375)

Biosystems and Agricultural Engineering Project Participants  Philip R. Goodrich PE, David Nelson PE, Richard Huelskamp, David Schmidt PE, R. Vance Morey from Department of Biosystems and Agricultural Engineering, University of Minnesota.  Dennis Haubenschild from Haubenschild Farms, Princeton MN  Matthew Drewitz, Paul Burns, from Minnesota Department of Agriculture Other participants in this project include: Amanda Bilik, The Minnesota Project, Verlyn Johnson and Blanca Martinez, BAE Henry Fischer, East Central Energy. Rob Lowen, Plug Power, Inc. Jamie Tooley, CES-Landtec Engineering Don White, Donaldson Corp David Thimsen, EPRI Claudio Martinez & Stephan Becerra,John Deere Co

Biosystems and Agricultural Engineering Thank you Advancing Utilization of Manure Methane Digester Funding for this project was recommended by the Legislative Commission on Minnesota Resources from the Minnesota Environment and Natural Resources Trust Fund