Interstate Power and Light plans scrubbers for four coal units

When the Phase 2 Clean Air Interstate Rule (CAIR) and Cross-State Air Pollution Rule (CSAPR) SO2 emission reduction periods begin in 2015 and 2014 respectively, Interstate Power and Light (IPL) plans to reduce its SO2 output through new scrubbers at Ottumwa Unit 1, Lansing Unit 4 and George Neal Units 3-4.

The George Neal units are operated by MidAmerican Energy, but partially owned by IPL, said Eric Guelker, employed by Alliant Energy Corporate Services, a service company subsidiary of IPL parent Alliant Energy. He is Director-Environmental Planning. IPL filed testimony from Guelker on April 2 at the Iowa Utilities Board in support of its latest clean-air plan.

In the previous air plan, IPL proposed to install scrubbers at two larger IPL generating units – Ottumwa and Lansing 4 – in 2014. These scrubbers would assist IPL in complying with the Phase 2 CAIR SO2 emissions requirements which begin in 2015 or the Phase 2 CSAPR SO2 emissions requirements that will be imposed in 2014.

In its current plan, IPL continues to propose installing scrubbers at these two generating facilities; however, it has delayed the planned in-service date for the scrubber at Lansing by one year, until 2015. This in-service date generally aligns with the timing of Phase 2 CAIR or CSAPR emission reduction requirements. In addition, due to changes in realized and projected emissions, resulting primarily from previously announced and planned operating changes at several IPL units, specific plan items have changed somewhat, such as the current and forecasted amounts of IPL’s accumulated, or banked, SO2 allowances, Guelker wrote.

Since 2010, when IPL filed its prior plan, IPL has gained greater certainty about future environmental rules and regulations, specifically the new Mercury and Air Toxics Standards (MATS) rule. IPL has also gained, Guelker said, further knowledge about the available choices for complying with the MATS rule as a result of mercury and other hazardous air pollutant (HAP) emissions testing and engineering analyses that it has performed at many of its coal-fired units.

IPL’s rationale for selecting additional air emission control projects to propose at this time focused on selecting projects to meet the compliance requirements of the final MATS rule at a targeted set of IPL generating units. This targeted set of generating units, IPL’s Tier II generating units, includes units that IPL does not plan to retire and at which it does not plan to use natural gas as the primary fuel source or install larger, more capital intensive air emissions controls to more significantly reduce SO2, particulate matter, mercury and other HAP emissions. IPL needs to undertake these air emission control projects at this time because these projects must be complete by April 2015 to comply with MATS. Without completing these projects, IPL will not be able to continue to operate these units.

Scrubbers can also help reduce other emissions

Greater synergies exist between scrubber installations and other existing or planned projects at Lansing 4 and Ottumwa than at other IPL coal-fired units.

First, the ability to leverage existing or planned Hg emission controls at Lansing and Ottumwa increases the cost effectiveness of these scrubber installations as compared to those at other locations. Since a baghouse or other more capital-intensive modification is needed at these units for effective Hg control, regardless of whether or not a scrubber is installed, the incremental cost of the scrubber is reduced.

Second, these proposed projects concentrate or continue to concentrate IPL’s larger capital investments in emissions controls at these two units. Concentrating its emissions control investments enables IPL to maintain flexibility to change the operations of other IPL coal-fired units to support compliance with emerging environmental rules and regulations, including those related to greenhouse gas (GHG) emissions, without exposing IPL and its customers to potential stranded investment at units where these changes occur.

Current IPL NOx emissions are less than the CAIR Phase 1 and CSAPR Phase 1 and 2 allowance allocation amounts and only about 10% larger than CAIR Phase 2 allowance allocation amounts. Thus, in its proposed plan, IPL is not proposing any additional NOx control projects.

IPL plans to comply with the final MATS rule at its coal-fired units by taking actions including: installing mercury control systems in conjunction with installation of scrubbers and baghouses at IPL’s larger coal-fired units that it operates (i.e. Ottumwa); and converting to primary operation on natural gas, typically as part of a transition to planned future retirement, at IPL’s smaller coal-fired units. Parts of this NOx-control section, by the way, are redacted in the public version of the Guelker testimony.

“Whereas IPL’s plan for its Tier I units has not significantly changed, IPL’s proposed plan for its mid-sized and smaller (Tier II and Tier III) coal-fired units has evolved significantly,” Guelker wrote. “In its prior plan, IPL acknowledged that it needed a better understanding of options for mercury emissions control, especially at its mid-sized coal-fired units. As a result, IPL increased its emphasis on mercury emission control testing and evaluation at these units by undertaking a mercury control testing program that it proposed in the 2010 Update. When the EPA proposed the MATS Rule in March 2011, IPL expanded the scope of the emission control testing and evaluation at its mid-sized units to also include PM emission control and reduction. As an outcome of this testing and evaluation, and with knowledge of the compliance requirements of the final MATS Rule, IPL’s plan for its Tier II coal-fired units has evolved to that included in this 2012 Update. IPL’s plan for its Tier III units also emerged, as a result of its integrated resource planning, since the time of filing of the 2010 Update.”

Companion April 2 testimony from Terry Kouba, Director-Generation at Alliant Energy Corporate Services, outlined the nameplate capacities and the tiers that the company’s coal units fall into.

  • Lansing 4, 260 MW, Tier I
  • Ottumwa 1, 715 MW, Tier I
  • Burlington 1, 212 MW, Tier II
  • M.L. Kapp, 217 MW, Tier II
  • Prairie Creek 1A, 16 MW, Tier II
  • Prairie Creek 3, 44 MW, Tier II
  • Prairie Creek 4, 130 MW, Tier II
  • Sutherland 3, 75 MW, Tier II
  • Sutherland 1, 33 MW, Tier III
  • Lansing 3, 32 MW, Tier III

Contractors lined up for some projects

An air plan report filed by IPL with the board on April 2 shows the status of various emissions control projects. For example, for the Lansing Unit 4 dry scrubber (circulating fluidized bed) project, scoping activities are currently underway and IPL will issue a request for proposals in early 2012. Equipment selection is expected in the second quarter of 2012 with construction activities beginning later in 2013. The project is currently expected to go into service in 2015. The 2015 tie-in outage schedule will be submitted to the Midwest ISO in the second quarter of 2012. MISO has 90 days to approve or deny the schedule.

A spray dryer absorber scrubber is planned for Ottumwa Unit 1. IPL has selected Burns & McDonnell and Babcock & Wilcox to complete detailed engineering, and begin fabrication and construction of the spray dryer absorber in 2012. Construction will continue in 2013 with start-up and commissioning scheduled for 2014. The 2014 tie-in outage schedule was submitted to MISO on Feb. 6. MISO has 90 days to approve or deny the schedule.

Also at Ottumwa Unit 1, for mercury control, IPL plans an activated carbon injection (ACI) system and pulse jet fabric filter baghouse. IPL has selected Burns & McDonnell and Babcock & Wilcox to complete detailed engineering and begin fabrication and construction of the ACI system and baghouse in 2012. Construction will continue in 2013 with start-up and commissioning scheduled for 2014.

The plan, by the way, features a detailed description of a wide range of emissions controls technologies that were considered by IPL.

For smaller, intermediate-load, coal-fired units, IPL will continue to consider converting boilers to burn alternative fuels, such as natural gas, instead of installing emission controls. “In 2011, IPL switched the Dubuque Generating Station (Dubuque) to a natural gas-fired facility and no longer operates the site as a coal-fired facility,” the plan noted. “IPL also plans to switch its Sutherland Generating Station (Units 1 and 3) from a coal-fired to a natural gas-fired facility. IPL expects to complete this fuel switching in the second quarter of 2012.”

At the current time, IPL is not planning to co-fire biomass at any of its coal-fired units due to the high cost of the biomass and issues associated with acquiring large quantities of that fuel. Co-firing of natural gas with coal, however, may provide an economic alternative to installing emission controls, the plan added.

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.