The Office of Consumer Advocate (OCA), a division of the Iowa Department of Justice, on Jan. 3 filed with the Iowa Utilities Board a brief that supports plans by Interstate Power and Light (IPL) for new air emissions controls on one coal unit and the conversion of two other coal units to natural gas.
The OCA was responding to an Emission Plan and Budget (EPB) filed by Interstate Power and Light on April 1, 2016. In its 2016 EPB, IPL proposed the following new major air related projects:
- Installation of selective catalytic reduction (SCR) technology at Ottumwa Generating Station Unit 1 (OGS) by the end of 2018;
- Conversion of Prairie Creek Unit 4 from coal to natural gas by the end of 2017; and
- Conversion of Burlington Unit 1 from coal to natural gas by the end of 2021.
IPL maintains that these actions, together with the actions it has taken to date in accordance with prior EPBs, will enable the company to cost-effectively comply with current and future environmental regulations. Asserting that the U.S. Environmental Protection Agency’s SO2 and NOx rules “have gotten—and are expected to continue getting—more stringent over time,” IPL has proposed to install SCR technology to further control NOx at OGS. In support of this conclusion, IPL relies on the consent decree that IPL entered into with the EPA, the State of Iowa, Linn County, and the Sierra Club “to resolve allegations that IPL violated the prevention of significant deterioration (PSD) provisions of the clean air act at various of its power plants.”
IPL asserts that if a future potential modification is necessary at OGS and triggers a PSD Clean Air Act permitting requirement to install Best Available Control Technology (BACT) for NOx, it would likely necessitate installation of SCR. IPL states that the three new air-related projects proposed in this proceeding are all needed to reduce NOx emissions to meet this proposed EPA rule revision in the ozone season. The major regulatory requirement governing NOx emissions from IPL’s facilities is the Cross-State Air Pollution Rule (CSAPR). The EPA NOx emissions requirements in recent years have been a moving target with the most recently adopted changes being less stringent than the original proposed changes.
Under the Consent Decree entered by the U.S. District Court for the Northern District of Iowa in September 2015, IPL, EPA, the State of Iowa, Linn County and the Sierra Club agreed to numerous provisions applicable to IPL coal-fired electric generating fleet, including a commitment to install SCR at OGS on or before Dec. 31, 2019, and thereafter to achieve and maintain an average emission rate for NOx at OGS of no greater than 0.080 lb/mmBTU.
Additionally, the parties to the Consent Decree agreed to plans to fuel switch two coal-fired units. IPL plans to converts Prairie Creek Unit 4 from coal to natural gas by the end of 2017. IPL also plans to convert Burlington from coal to natural gas by 2021. IPL did not include a budget amount for the Burlington fuel switch project in its EPB. The fuel switching of Prairie Creek Unit 4 is expected to be significantly less capital intensive than the SCR project. Also, by switching fuels, IPL is able to avoid investing in any additional environmental control device at these plants.
Said the Jan. 3 OCA brief: “Given these potentialities, the SCR could be considered necessary under federal ambient air quality standards and consistent with electric reliability considerations…. OCA further finds the fuel switching at Prairie Creek Unit 4 reasonable. OCA is not able to determine the reasonableness of the fuel-switching at Burlington Unit 1 because no budget has been proposed, but this can be addressed in future filed EPBs. For these reasons, OCA does not challenge these projects being included in IPL’s EPB.”
In other recent actions related to Interstate’s plans:
- IPL on Dec. 15 asked the Iowa Utilities Board for a declaratory order saying that its planned cessation by the end of 2017 of coal-fired generation at Unit 4 of Prairie Creek is not a “significant alteration” that would require a full board proceeding. Prairie Creek consists of three generating units (1A, 3, and 4) that have a collective net summer and winter capacity of approximately 163 MW. Prairie Creek Unit 4 was originally placed into service in 1968 and has a net summer and winter capacity of approximately 116 MW. This unit is currently capable of combusting coal or natural gas. Historically, the unit has operated as a baseload facility, but will likely operate as an intermediate or peaking facility once it begins running exclusively on natural gas.
- The Iowa Department of Natural Resources was out for comment until Dec. 18 on draft amendments to a Prevention of Significant Deterioration Air Quality construction permit for the Ottumwa plant. This permitting includes a requirement to install and continuously operate SCR. The Ottumwa Generating Station (OGS) is located in southeast Iowa, about 100 miles southeast of Des Moines near the Des Moines River. There is one boiler at the plant. It is a twin-furnace tangentially-fired pulverized coal boiler that typically burns Wyoming Powder River Basin (PRB) sub-bituminous coal. OGS is currently capable of producing electricity during a maximum cruise operating condition at a rate of 673 MWe (net). IPL operates the unit and has a 48% ownership share. MidAmerican Energy owns the other 52%. The facility began operation in 1981.