NextEra seeks to reconnect Duane Arnold to the grid

Wednesday, 6 August 2025

The single-unit 615 MWe boiling water reactor plant was taken out of service in 2020 after more than 45 years of operation. The plant was the only operating nuclear unit in Iowa and had been producing around 9.2% of the state's electric generation and 19% of its emission-free electricity, but the decision to close it was made in 2018 when utility Alliant Energy and owner NextEra Energy Resources agreed to shorten their existing power purchase agreement by five years, ending in 2020 rather than 2025.

The plant had been scheduled to shut in October 2020, but did not return to service after a severe storm in August that year damaged its cooling towers. The reactor itself was not damaged.

In July last year, NextEra confirmed that it is looking into restarting the Duane Arnold nuclear power plant. In January this year, the company filed a licensing change request for Duane Arnold with the US Nuclear Regulatory Commission.

"In response to then-prevailing market conditions following the decommissioning of Duane Arnold in 2020, [the plant's] original interconnection rights were divided to support the prospective development of multiple solar generating facilities," NextEas noted in its FERC filing. "Since that time, there has been an unprecedented increase in electrical demand from commercial and industrial customers, with an emphasis on high-capacity, reliable, low-emissions power."

The company said that instead of developing a solar energy project at the site, it now plans to "reaggregate Duane Arnold's original interconnection rights to accelerate the recommissioning of the facility".

Although the Duane Arnold reactor has been defuelled - all of its fuel is now in an on-site dry storage facility - the buildings are not scheduled to be demolished until 50 years have passed. This deferred approach to decommissioning, with the facility placed into a safe storage configuration with eventual dismantling and decontamination activities taking place after residual radioactivity has decayed, is sometimes referred to as SAFESTOR.

"The recommissioning of Duane Arnold represents an opportunity to return over 600 MWe of retired nuclear generation capacity to service," NextEra said. "Duane Arnold is one of the last viable nuclear recommissioning opportunities in the United States, presenting a unique opportunity to add new nuclear generation to the grid before the end of the decade."

Duane Arnold is not the only shuttered US plant being returned to service. Last month, the US Nuclear Regulatory Commission approved a series of licensing and regulatory actions that will allow fuel loading at Holtec's Palisades plant in Michigan, which ceased operations in May 2022. Meanwhile, unit 1 of Constellation's Crane Clean Energy Centre - formerly known as Three Mile Island - was closed in 2019, but last year the company announced plans to restart the unit after it signed a 20-year power purchase agreement with Microsoft.