Iowa city nears air permit for coal-to-gas conversion at Ames power plant

The Iowa Department of Natural Resources is taking comment until June 23 on a draft air permit that would allow the City of Ames at its Steam Electric Plant to switch two boilers from burning coal to consuming natural gas.

The power plant is owned and operated by the city’s electric utility, Ames Municipal Electric System, and is located in Ames in Story County. The City of Ames (COA) on March 9 submitted this Prevention of Significant Deterioration (PSD) construction permit application for the proposed modification of two existing coal- and refuse derived fuel (RDF)-fired boilers to burn natural gas and RDF. The proposed modifications are anticipated to increase the total capacity of the plant to 1,251 mmBtu/hr fuel input.

The revamped boilers will be designed to utilize the RDF currently used in the boilers along with pipeline-quality natural gas. Two new cooling towers not subject to PSD will also be included as part of the project.

The City of Ames is obligated to manage the waste collected in the city by either burning or landfilling. The cost structure greatly favors burning the RDF in these boilers, the department noted. Therefore the incentive for Ames is to dispose of all the RDF in the boilers if possible. For this reason it is expected that these boilers will operate only on natural gas for startups or if there is no RDF available.

Boiler 7 will, with this fuel conversion, go from 433 to 476 mmBtu hr. Boiler 8 will go from 761.2 to 775 mmBtu/hr.

Interstate Power and Light (IPL) applied Feb. 11 at the Iowa Utilities Board for an approval to construct the Ames Lateral, a high-pressure distribution pipeline that will in part serve the converted Ames plant. The pipeline would run from the DuPont Regulation Station facility in a southwesterly direction to a proposed terminus point at the Barilla Regulation Station facility located in Story County. The outlet of the proposed Barilla Regulation Station will tie into the existing Ames 120 psig gas distribution system which will provide the supply needed to serve the City of Ames Municipal Power Plant as well as increase the gas reliability of the Ames natural gas distribution system. The proposed 2.36 mile Ames Lateral will be designed to deliver up to 52,000 Mcf/day.

“Construction of the proposed pipeline promotes the public convenience and necessity by allowing IPL to fulfill its obligation to meet the natural gas supply needs of its existing and future customers, and to enhance reliability,” said the Interstate application. “Switching the Ames Power Plant’s fuel source from coal to natural gas will reduce plant emissions which will benefit the public.”

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.