Landmark Biodiesel Tests: Winterset, Story City

In October 2004, an IAMU experiment at the Sumner Municipal Light Plant measured emissions from the use of biodiesel in diesel generators. The test was the first of its type in the nation and led to rule changes by the Iowa Department of Natural Resources regarding the usage of biodiesel in stationary diesel generation. This fall, a collaborative initiative between IAMU, municipal utilities and others made a second round of biodiesel testing possible. One of these tests is again believed to be the first of its type in the nation, and the results of all tests could not only open the door further to another renewable energy source for Iowa’s utilities, but could also reveal possible side effects of biodiesel in generators.

From September 25 to October 5, tests took place at Winterset Municipal Utilities (WMU) and Story City Municipal Utilities (SCMU). WMU monitored emissions from 100% diesel, 10% biodiesel (B10), and 20% biodiesel (B20) in two of their generators: a 1750 kW Cooper-Bessemer (in-service year 1966) and a 1825 kW Caterpillar (in-service year 2002). In Story City, 100% diesel, B10, B20, and B100 emissions were measured in a 2070 kW Fairbanks Morse unit (in-service year 1972). The B100 test in Story City is believed to be the first such test on an older generator, and the first B100 emissions test done in accordance with U.S. Environmental Protection Agency (EPA) methodology. The B10 and B20 data from both utilities are also some of the very first emissions tests done according to EPA methodology.

The B20 and B100 tests measured particulate matter (PM), carbon monoxide (CO), and nitrogen oxide (NOx) emissions, while the B10 tests measured NOx and CO emissions.

The Iowa Department of Natural Resources (IDNR) will compare the biodiesel emissions with the emissions from 100% diesel runs in order to determine the effect of biodiesel on engine emissions. Dr. Song-Charng Kong of Iowa State University will also use the results of these tests in a tool he is developing to more closely model engine geometries. Results are not yet available but will be featured in an upcoming edition of the IAMU Newsletter.

The fact that EPA methodology was used is important because the IDNR will only recognize data collected in this manner, and the IDNR currently requires these tests from each entity interested in burning blends higher than B10. The requisite EPA tests are expensive enough to act as a major deterrent for utilities wishing to burn biodiesel blends. Consequently, IAMU believes that the WMU and SCMU test data could not only influence regulatory decisions regarding the usage of biodiesel in diesel generation, but may also make it cheaper and easier for more utilities to use biodiesel in the future.

While test results could be very useful for research and regulatory purposes, the testing periods themselves also provided insights for utilities about the day-to-day usage of biodiesel in generators. IAMU monitored data such as power output, fuel quality samples, and generator fuel consumption, in order to provide more information about biodiesel usage in electric generators. IAMU expects to provide this information, along with finalized emissions results, in a later edition of the Newsletter.

IAMU reminds members that diesel generator operators currently cannot use biodiesel blends higher than B2 in the generators without notifying the IDNR. Due to the 2004 Sumner Municipal Light Plant tests, generators can run on B3-B10 if the IDNR has been notified and necessary changes have been made to applicable operating or construction permits (the changes are based on the Sumner data). However, utilities desiring to run on blends higher than B10 must conduct emissions testing using Environmental Protection Agency (EPA) methodology before the IDNR will consider making an allowance.