Iowa Utilities Board to reconsider Alliant Energy’s advance ratemaking principles

The Iowa Utilities Board (IUB) issued an order granting consideration to an earlier order denying Interstate Power and Light Company’s (IPL) advance ratemaking principles application.

IPL is a subsidiary of Alliant Energy. In November, the IUB denied the IPL’s application after finding it didn’t meet Iowa’s statutory requirements. IUB said the application did not demonstrate that the proposed Duane Arnold Solar I and Duane Arnold Solar II projects, an additional 200 megawatts of solar generation, and a battery storage project were reasonable when compared to other alternative sources of electricity.

Later that month, IPL filed a motion for reconsideration or rehearing. The Iowa Department of Justice’s Office of Consumer Advocate filed an objection to IPL’s motion but said it did not oppose a rehearing if IUB requires IPL to provide specific additional information. A joint filing by the Environmental Law & Policy Center and the Iowa Environmental Council recommended IUB reconsider IPL’s application.

IUB said there is no basis for a reversal of its decision, but there was potential new and updated evidence that would allow IPL to meet the statutory requirements regarding the two Duane Arnold solar facilities. IUB granted the reconsideration to allow IPL the opportunity to file additional evidence. However, the order denies any reconsideration for the additional 200 megawatts of solar generation and the battery energy storage system.

IPL will have 30 days to file an updated economic analysis based on updated costs and market prices; an analysis of cost-per-unit of accredited capacity; an economic analysis of IPL building and owning a natural gas simple-cycle combustion turbine; the availability and pricing of a power purchase agreement with NextEra Energy Resources for generation from the solar facilities; an economic analysis of available PPAs from sources of electricity other than solar; and an analysis of the Inflation Reduction Act of 2022 and its impact on the electric market and other sources of supply.

Once IPL files its additional evidence, other parties will have 20 days to file their responses. IUB will then consider whether the additional information shows that the two solar facilities are reasonable.