Montana Renewables plans to increase sustainable aviation fuel (SAF) production to about 200 million gallons per year (MMgy) by 2028 after completing the initial phase of its MaxSAF 150 expansion programme.
Montana Renewables, an unrestricted subsidiary of Calumet Inc., completed the first phase of the project earlier this year on schedule and within the planned budget, Biomass Magazine reported.
The company is now preparing for the next stage of the expansion, which is expected to further increase SAF production capacity.
In October 2024, Montana Renewables received a conditional commitment for a $1.44 billion loan guarantee from the US Department of Energy to support the proposed MaxSAF initiative. The original project was designed to increase annual production at the biorefinery to 330 MMgy, including 300 MMgy of SAF and 30 MMgy of renewable diesel.
Under the original plan, around half of the proposed 300 MMgy SAF capacity was expected to be operational by 2026, with the full project scheduled for completion in 2028. The first phase was initially estimated to require $150 million to $250 million in capital.
Calumet later announced in 2025 that it would pursue a smaller and more streamlined expansion. The revised plan was aimed at increasing SAF capacity from 120 MMgy to 150 MMgy in early 2026, with estimated capital spending of only $20 million to $30 million.
The streamlined project mainly involved catalyst work and changes to the configuration of existing assets.
During Calumet’s second-quarter earnings call on August 7, President and CEO Louis Borgmann said Montana Renewables had completed performance testing of the newly installed MaxSAF catalyst and that the results met or exceeded expectations.
“With the first step of MaxSAF behind us, we’ll turn our efforts to the next steps of the expansion,” Borgmann said.
Second reactor to support higher SAF output
Instead of transporting a second reactor from the Gulf Coast, Montana Renewables plans to reconfigure some of the assets already operating at its Great Falls, Montana, facility.
Borgmann said bringing the second reactor into SAF production would help achieve higher SAF yields.
He said the standard industry process for producing SAF involves fractionating and isomerising renewable diesel. This process also produces lower-value by-products such as naphtha and fuel gas.
According to Borgmann, when renewable diesel margins are strong, the economics can favour producing renewable diesel rather than converting more of it into SAF, even when SAF commands a premium.
The second phase of MaxSAF 150 will instead use the second reactor in a patent-pending polishing process rather than more severe cracking. The company expects this approach to minimise by-products and make higher SAF production more economically attractive.
Montana Renewables expects the second SAF reactor to begin operating this winter. The facility is currently producing SAF at a run-rate of about 60 MMgy.
Once the second reactor is operational, the company expects SAF production to increase to 80 MMgy to 100 MMgy by the end of the year. The run-rate is expected to rise above 120 MMgy by spring 2027, before SAF production reaches about 200 MMgy in 2028.
Calumet’s Montana Renewables segment reported adjusted EBITDA with tax attributes of $26.6 million in the second quarter, compared with $16.3 million during the same period last year.
