Alliant subsidiary advances emissions projects at Iowa coal plants

 Alliant subsidiary advances emissions projects at Iowa coal plants

Caption: Lansing Generating Station

Interstate Power and Light (IPL), which is a subsidiary of Alliant Energy (NYSE: LNT), told the Iowa Utilities Board that it is undertaking a number of emissions-control projects for coal-fired capacity under its approved Emission Plan and Budget (EPB).
 
The utility is mandated to periodically update the board on its EPB-related activities. In 2014, IPL pursued the following emissions-related activities:
•Began construction of the SO2 scrubber at IPL’s Lansing Generating Station Unit 4 to reduce SO2 emissions.
•Completed all major construction at IPL and MidAmerican Energy’s Ottumwa Generating Station related to the SO2 scrubber and baghouse emission control project that supports compliance with the federal Mercury and Air Toxics Standards (MATS) and Cross State Air Pollution Rule (CSAPR).
•Completed energy efficiency projects at Ottumwa Generating Station.
•Advanced completion of emission control projects at Burlington and Prairie Creek Generating Stations to support compliance with MATS.
•Continued to pursue options to resolve SO2 allowance forward contracts in customers' best interest.
 
The following summaries provide an update of the specific activities for facilities with on-hold, in-progress and proposed emissions control projects as identified in IPL’s April 2014 EPB update.
 
Lansing Generating Station Unit 4
•Low Nitrogen Oxide (NOx) Burners (LNB) and Selective Catalytic Reduction (SCR) - The LNB and SCR went into service in July 2010, and the projects were closed in May 2011. The SCR was designed to hold three layers of catalyst. During the construction of the SCR the decision was made to only install two layers. The existing two catalyst layers are showing signs of routine deactivation and required an additional layer or replacement of the existing layers to maintain SCR removal efficiency. A third layer of catalyst was purchased and installed in September 2014. The existing two catalyst layers are now within the manufacturer’s expected replacement window. As part of the ongoing long-term catalyst management plan, a replacement layer is being purchased for installation in the spring of 2015.
•Mercury (Hg) Control - IPL has completed testing at Lansing Unit 4 and validated the ability of the Activated Carbon Injection System (ACI) and baghouse to remove Hg and particulate matter (PM) to the levels required by the MATS rule.
•SO2 Control – Circulating Fluidized Bed (CFB) Dry Scrubber - The installation of a Lansing Generating Station CFB is progressing as planned. Detailed engineering and procurement activities are predominantly complete. All major equipment and material have been delivered to the site. Construction of the CFB began in June 2014. The CFB is scheduled to start-up in May and be in-service by the end of July 2015.
 
Ottumwa Generating Station Unit 1
•Hg Control - Detailed engineering, fabrication and construction of the ACI system and baghouse began in 2012 and continued, as scheduled, in 2013 and 2014. Fabrication and construction of the ACI system and baghouse was completed in November 2014. Start-up and commissioning commenced following the tie-in outage completion in November 2014. IPL has conducted preliminary testing that demonstrates the ability of the ACI system and baghouse to remove Hg and PM to the levels required by the MATS rule.
•SO2 Control-Spray Dryer Absorber (SDA) Dry Scrubber - Detailed engineering, fabrication and construction of the SDA scrubber began in 2012 and continued in 2013 and 2014. Fabrication and construction of the SDA continued until November 2014. Start-up and commissioning began following the tie-in outage completion in November 2014. IPL intends to comply with the Utility MATS Hydrogen Chloride emission limit requirements through the use of SO2 removal as a surrogate, per the rule. IPL has conducted preliminary testing of the SDA’s SO2 removal performance. The testing demonstrates the the ability of the SDA to reduce SO2 to levels under the MATS rule.
•Energy Efficiency Projects - The Comprehensive Asset Management Program (CAMP) includes the Steam Turbine/Generator Upgrade Project that will improve plant heat rate, plant output, and steam turbine/generator reliability. This project replaced the existing steam turbine high pressure (HP), intermediate pressure (IP) and low pressure (LP) rotors and inner shells, as well as the generator stator rewind. Installation was completed during the tie-in outage that ended in November 2014. Start-up and commissioning was completed in December 2014.
 
Burlington Generating Station Unit 1
•PM Control - To further control PM emissions from Burlington Unit 1, a liquid flue gas conditioning system was installed in 2014 and the Electrostatic Precipitator (ESP) was upgraded through sectionalization. Both projects were completed during the 2014 fall outage. To demonstrate continued compliance, a PM Continuous Emission Monitor System (CEMS) was also installed and certified in 2014. All systems are now in place to meet and demonstrate compliance with the limits going into effect in April 2015.
•Hg Control - To address Hg emissions, calcium bromide and ACI systems were installed on Burlington Unit 1 in 2014. The calcium bromide system applies the additive pre-combustion and the activated carbon is injected post-combustion; the combined effect results in lowered Hg emissions. Both projects were completed on budget and on schedule in late 2014 and are in service. All systems are now in place to meet and demonstrate compliance with the limits going into effect in April 2015. All of the aforementioned systems will continuously operate at Burlington Generating Station and will facilitate compliance with the MATS rule. Given the chlorine content of the Powder River Basin coal used at Burlington, no controls will be required to address acid gas emissions.
 
Prairie Creek Generating Station Unit 3
•PM Control - To further control PM emissions, a liquid flue gas conditioning system was installed on Prairie Creek Unit 3 in 2014 and the ESP was upgraded through sectionalization. Both projects were completed during the 2014 fall outage. To demonstrate continued compliance, a PM CEMS was also installed and certified in 2014. All systems are now in place to meet and demonstrate compliance with the limits going into effect in April 2015.
•Hg Control - To address Hg emissions, calcium bromide and ACI were installed on Unit 3. The calcium bromide system applies the additive pre-combustion and the activated carbon is injected post-combustion; the combined effect resulting in lower Hg emissions. To demonstrate continued compliance, a mercury CEMS was installed. Both control projects and the new monitor are now in service. All systems are now in place to meet and demonstrate compliance with the limits going into effect in April 2015. All of these systems will continuously operate on Prairie Creek Unit 3 and will facilitate compliance with the MATS rule. Given the chlorine content of the Powder River Basin coal used at Prairie Creek, no controls will be required to address acid gas emissions.
 
Prairie Creek Generating Station Unit 4
•PM Control - To further control PM emissions, the ESP was upgraded through sectionalization; that project was completed during the 2014 fall outage. To demonstrate continued compliance, a PM CEMS was also installed. All PM control systems are now in place to meet and demonstrate compliance with the limits going into effect in April 2015.
•Hg Control - To address Hg emissions, calcium bromide and ACI systems were installed on Prairie Creek Unit 4. The calcium bromide system applies the additive pre-combustion and the activated carbon is injected post-combustion; the combined effect resulting in lower Hg emissions. To demonstrate continued compliance, a mercury CEMS was also installed. All systems are now in place to meet and demonstrate compliance with the limits going into effect in April 2015. All of the aforementioned systems will continuously operate on Prairie Creek Unit 4 and will facilitate compliance with the MATS rule. Given the chlorine content of the Powder River Basin coal used at Prairie Creek, no controls will be required to address acid gas emissions.
 
M.L. Kapp Generating Station
•Conversion to Natural Gas - IPL was informed by the Midcontinent ISO that, given the projected reduction in capacity associated with fueling M.L. Kapp on natural gas, that IPL should file an Attachment Y notice with MISO. IPL filed an Attachment Y Notice on Jan. 30. MISO has indicated to IPL that its review of this notice could take up to 26 weeks. In the event MISO takes the full 26 weeks (up to July 31, 2015), MISO’s review and response to IPL’s Attachment Y notice would extend beyond IPL’s April 2015 MATS compliance date for M.L. Kapp. Accordingly, on Feb. 23, IPL filed a request with the U.S. Environmental Protection Agency for a one-year Utility MATS compliance extension. On March 26, IPL received an approved one-year MATS extension from EPA, which will enable M.L. Kapp to continue to operate on coal while MISO completes its review of the Attachment Y notice. The MATS extension is valid until April 16, 2016. As a condition of the extension approval, M.L. Kapp is required to co-fire the maximum amount of natural gas as possible to minimize emissions.
 
Plant decommissioning work also ongoing
 
Generating plants that have been retired by IPL will be subject to decommissioning. Decommissioning activities undertaken at the Sixth Street Generating Station in 2014 included preparation of site for building removal and finalizing closure options for the existing ash ponds. Decommissioning planning continued for the Dubuque Generating Station, although no firm activities have been identified or scheduled.
 
IPL expects to complete the demolition of the Sixth Street Generating Station in 2015, and will begin implementation of the ash pond closure plan. Additional planning may occur at other IPL facilities if all units at a location will be retired. The actual steps to decommission a facility will depend on many factors including but not limited to: end use evaluation of the facility and site; environmental site assessments; and site location issues such as safety and security.
 
Optimization of the various emission control systems begins shortly after commissioning, the utility noted. IPL uses engineering and statistical processes to determine the optimum quantities of consumables that will provide the maximum emission reduction for the lowest cost. For example, at Prairie Creek Unit 4, optimization analysis revealed that the volume of ACI and calcium bromide could be reduced by 74% and 23%, respectively, from the quantities originally proposed by the manufacturer and still achieve the required Hg removal.

This article was republished with permission from



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