Haubenschild Farms Final Report - The Minnesota Project

The Minnesota Project August 2002
Results to Date
In September 1999, construction was complete and the manure began to be fed to the
digester. On September 9, the engine was started using propane in order to heat the manure
in the tank. By October 1, biogas production was sufficient to fuel the engine.
Electricity and Biogas Production
Figure 2 shows the production of biogas and electricity by the installation from October 1,
1999 until July 7, 2000. As the bacteria in the digester have grown and flourished, and as
the herd size was expanded, the measured biogas output of the digester steadily increased
from about 30,000 cubic feet/day of biogas in October 1999 to about 70,000 cubic feet/day
by July 2000, where it has remained fairly constant.
Figure 2: Measured Biogas and Electricity Production to Date 20
160
90,000
140
80,000
Electricity Production
(kW)
120
100
80
60
40
20
Electricity Production, weekly
average (kWh/hr)
Average Daily Biogas Production,
1 week average (cubic feet/day)
70,000
60,000
50,000
40,000
30,000
20,000
10,000
Biogas Production
(cubic feet/day)
0
0
1-Oct-99
3-Dec-99
4-Feb-00
9-Apr-00
9-Jun-00
11-Aug-00
13-Oct-00
15-Dec-00
16-Feb-01
20-Apr-01
22-Jun-01
24-Aug-01
26-Oct-01
28-Dec-01
1-Mar-02
3-May-02
5-Jul-02
20 Biogas volume is calculated from meter readings of biogas going into the generator. If the generator is
down or cannot accomidate the full volume of biogas produced, the biogas is flared and will not be metered.
During engine down time, biogas production is estimated from the average biogas production during engine
operating hours on a weekly basis. However, since at least July 2000, the digester has been producing excess
biogas that cannot be accommodated even with the engine in service, so full biogas production is not known.
20