Minnesota regulators voted unanimously Feb. 28 to require that Amazon demonstrate a need for a 250-unit fleet of backup diesel generators at its proposed data center in the central portion of the state.

The Minnesota Public Utilities Commission rejected Amazon’s late December petition to sidestep the state’s certificate of need process for its planned data center campus in Becker (CN-24-435).

During the meeting, Commissioner Joe Sullivan said his mind was “gravitating” toward the plain language of the state statute, which stipulates that any developer of a power plant capable of 50 MW or more must prove the facility is essential over cleaner or more inexpensive alternatives.

Amazon’s planned diesel fleet could generate as much as 600 MW. However, attorneys for Amazon and local labor union representatives argued that the generators should sidestep permitting because they would be strictly for emergency backup, not be connected to the grid and not affect ratepayers.

The topic has also reached the Minnesota Legislature, where Republicans are sponsoring a bill to change state law to exempt Amazon from a certificate of need. If passed, the PUC’s decision to require Amazon’s justification could be moot. The involvement of regulators and legislators demonstrates the uncharted territory of how hundreds of acres of proposed data center should be regulated.

Minnesota Department of Commerce associate counsel AnneMarie Curtin argued that state law is clear in that Amazon’s proposed emergency power fleet meets the definition of a large energy facility that requires a certificate of need.

Commissioner John Tuma said the sheer number of diesel generators proposed by Amazon is a “little shocking.”

“These are not expected to run more than a few times a year and less than 15 hours a year for the regular testing and maintenance that’s required for those systems,” argued Christina Brusven, appearing on behalf of Amazon Web Services. She said similar generators are stationed outside hospitals and government centers, albeit on a smaller scale.

Commissioner Hwikwon Ham pointed out that a “huge load” like Amazon’s that can drop suddenly from the MISO system can trigger an over-frequency event, especially considering the nearby “sensitive” Monticello Nuclear Generating Plant. He said he wondered whether Amazon’s proposed backup would be able to handle such a situation and said he would raise the issue during the certificate of need proceeding.

Tuma said perhaps behind-the-meter generation is not the best way to handle backup power at a site with such large power needs. He urged both Xcel Energy and Amazon to reexamine their ideas about the most appropriate source of emergency power.

“Maybe we can figure out something that benefits both the grid and the system and keeps it safe because, ‘This is a large load dropping off’ does scare me. These are loads that we are not used to dealing with. … This is something that’s new, and we need to understand what it means for the security of the system,” Tuma said. He urged Xcel to prepare answers on how the load could reliably trip offline and “meaningful alternatives” to the diesel fleet.

“I keep hearing from these Amazons and all these [companies] that they want to do the right thing, and they want clean energy, and that’s why they want to plop their data center right next to that solar facility, so I want to hear that those discussions have happened,” Tuma said.

Commission Chair Katie Sieben asked why Amazon did not simply file a certificate of need with its site permitting materials and then lobby for the bill in the legislature. She said it is “frustrating” that Amazon continues to “squeeze” the commission over ambiguous language in state law. She suggested that Amazon might sue the commission if the law is passed.

Brusven said it’s not Amazon’s goal to put the commission in a “difficult position.”

“It is. You did,” Sieben responded and suggested that Amazon could have been “farther along” in the permitting process at this point had it already opted to explain its need.

Sieben said she expected interested parties in the forthcoming certificate of need process to push Amazon for more environmentally friendly options like biodiesel.