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Alliant closes 127-year-old Iowa coal plant 6 years after switching to gas


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Alliant closes 127-year-old Iowa coal plant 6 years after switching to gas

A fossil fuel-fired power plant in eastern Iowa has ceased operations after roughly 127 years of generating electricity. Alliant Energy Corp. shuttered its 70-MW gas-fired Dubuque facility in Dubuque County on May 28.

Company spokesman Mike Wagner said the plant was built as a coal-fired generator around 1890 and had an original capacity of 9.5 MW before it was acquired by Alliant in 1925. Operated by Alliant's Iowa subsidiary, Interstate Power & Light Co., the plant continued to run on coal until 2011, when stringent federal emissions regulations forced a switch to cleaner natural gas.

Since its gas conversion, the plant has been used as a 'peaker' plant in periods of high energy demand. However, Dubuque had not been used to meet peak demand since March as a result of declining energy use and energy demand, Wagner said. As the plant undergoes decommissioning and eventual demolition, Alliant will be upgrading a 161-kV substation that services the nearby town of Dubuque and was associated with the plant.

Alliant originally sought to retire the Dubuque plant by the end of 2014 but postponed the shutdown at the request of the Midcontinent ISO. At the time, the regional grid operator determined the plant could not be retired so soon without impairing the grid's reliability.