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| The new plume at Harding Street Station, which is largely comprised of water, is similar in appearance to a cumulus cloud. |
As part of its ongoing commitment to protect and preserve the environment, IPL recently completed the installation of a new scrubber with a 565-foot stack to dramatically reduce emissions at the company's Harding Street Station. Construction of the scrubber, more technically known as a flue gas desulphurization system (FGD), has been one of the most significant recent projects in Indianapolis in terms of economic impact. IPL and its customers invested more than $200 million in the scrubber project and the work involved up to 350 skilled-trades construction workers on-site at once. Implementation of the scrubber also created 18 new full-time IPL positions.
The scrubber is expected to reduce sulfur dioxide (SO2) emissions by 97% on Harding Street Station’s Unit 7. It removes SO2 and mercury through the injection of a water/limestone slurry. The process creates flue gases that are heavy in moisture content, which changes the visual characteristics of the stack plume, resulting in an effect similar to the cotton-like look of a cumulus cloud. Check out the detailed Fact Sheet for more information about the scrubber.
Along with installing the scrubber, IPL has constructed:
• a new material handling building for limestone, which is used in the scrubber, and
• a new handling building for gypsum, a byproduct of the scrubbing process that can be recycled.
In addition to the scrubber, IPL installed a Selective Catalytic Reduction (SCR) system on this same unit in June 2005 to reduce nitrogen oxide (NOx) emissions. Since the completion of the $55 million SCR project, IPL has reduced NOx emissions by more than 87% on Unit 7.
Combining SCR equipment and a scrubber not only removes NOx and SO2 but also reduces mercury emissions. Mercury emissions are expected to be reduced by 45% from a combination of the SCR and scrubber.
IPL continues to invest to improve its power plants’ performance and to help keep rates low. At the same time, these investments promote economic development by providing construction jobs for our community and an improved environment for our citizens.
Updated September 2007
