Montana’s largest private utility, NorthWestern Energy, recently released a benefit-cost study of distributed solar (i.e. rooftop solar) on its grid. The study was meant to clarify key questions about these solar systems, however initial review reveals that the findings appear questionable and its work will need to be checked for validity. Until this can be done, the study’s findings remain in doubt.
Unfortunately, the document that was released does not contain enough information to verify its claims. No work papers, spreadsheets, or other supporting sources of data were released, making it exceedingly difficult at this time to check the models and data inputs for the study. This unusual decision by the utility to limit transparency would seem counterintuitive given the purpose of the study was to create clarity, not ambiguity.
Nevertheless, MEIC will be reviewing the study and looks forward to continued participation in the discussion about rooftop solar in Montana.