Montana judge James A. Manley had previously ruled that the state’s Public Service Commission (PSC) had violated the rights of developer MTSUN by cutting both the rates paid for electricity and contract lengths under the Public Utility Regulatory Policies Act of 1978 (PURPA), for the express purpose of undercutting the viability of solar power. This was in contrast to taking into consideration standard avoided cost and other values as PURPA dictates.
Now, the same judge has set the rates and terms (pdf) for solar projects under PURPA. The judge ruled that the commission must compare this 80 MWac project to an 18 MW internal combustion engine (as per the utilitity’s 2015 IRP) to determine avoided cost, and that this value is $28.68/MWh. This value was agreed to by the utility, Northwestern Energy, and the developer prior – before the cut in rates that led to this case. Additionally, roughly $9.95/MWh must be paid as a price for carbon. Lastly, the judge set contract length at 25 years.