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Data Center to lease old Rainbow Powerhouse from NorthWestern Energy

Jul 30, 2019

Butte, Mont. – After almost a decade of work to explore options to use the century-old original powerhouse at Rainbow Dam for a new purpose, NorthWestern Energy submitted a plan to the Federal Energy Regulatory Commission that calls for the facility to be leased to a company for a blockchain model data center. If approved by FERC, Susteen Inc., an Irvin, Calif.-based company, will lease the facility. 

“This remarkable effort included creative vision to explore options that fit the unique safety and security requirements for this facility, located in close proximity to an active utility plant,” said NorthWestern Energy Director of Environmental and Land Permitting and Compliance Mary Gail Sullivan. “This project would not have developed without the commitment of NorthWestern Energy and the members of the Cascade County Historical Preservation Old Rainbow Powerhouse Repurposing Committee. The committee looked long and hard for an acceptable use of the building. Susteen was a pleasant surprise.”

NorthWestern Energy bought Rainbow hydro facility in 2014 from PPL Montana and committed to continue working with the Cascade County Historical Preservation Old Rainbow Powerhouse Repurposing Committee to look for alternative uses for the original powerhouse.

A new, more efficient powerhouse was commissioned at Rainbow Dam in 2013.

NorthWestern Energy provided $50,000 for a feasibility study for alternative uses for the original powerhouse.

Susteen is a technology company established in 1992 specializing in digital forensics, providing hardware and software products to international law enforcement and government agencies. Equipment for its new digital currency division will occupy the powerhouse. Susteen views the powerhouse’s structural soundness, size, and secure location, as ideal for its needs.

“Susteen is excited to bring cutting-edge technologies and breakthrough ideas to the Rainbow Powerhouse,” said Tom Sanders, Susteen’s chief technology officer. “We hope to establish our official historical building status, start improvements and open our Ethereum-powered blockchain data center quickly.  We have much to do over the coming months and are looking forward to engaging with the community in Cascade County and Great Falls.”

Construction on the 80-foot-wide and 326-foot-long original Rainbow Powerhouse began in 1909 and was completed in 1910, along with the dam and the power line. Electricity was first transmitted to Butte in 1910. Additions were completed in 1916 and 1930.

“Bringing a new industry to our community and having a new business investing in the county is a huge win for Cascade County,” said Cascade County Commissioner Jane Weber, who is a member of the Cascade County Historical Preservation Old Rainbow Powerhouse Repurposing Committee. “This project is about economic development with the bonus of retaining a well-loved and appreciated historic building on the landscape.”

"Historic preservation hitched to economic development is a happy marriage,” said Peter Jennings, vice president of the Historical Preservation Advisory Committee. “This project is the result of applied faith and persistence by local visionaries and opportunity on the world wide web. We are grateful to NorthWestern Energy for their disciplined and engaged partnership, and we welcome Susteen's enterprising spirit bringing internet-era industry to the old Rainbow Powerhouse and Cascade County."

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About NorthWestern Energy (NYSE: NWE)
NorthWestern provides electricity and / or natural gas to approximately 726,400 customers in Montana, South Dakota, and Nebraska. We have generated and distributed electricity in South Dakota and distributed natural gas in South Dakota and Nebraska since 1923 and have generated and distributed electricity and distributed natural gas in Montana since 2002. More information on NorthWestern is available on the company’s website at

Media Contact:
Jo Dee Black
(866) 622-8081

Jane Weber, Cascade County Commission

Peter Jennings, City-County Historic Preservation Advisory Commission

Susteen Inc.

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