The "Montana Solar Shares Act" establishes a framework for shared solar energy facilities in Montana, distinguishing shared solar customers from net metering customers. The bill defines key terms such as "on-bill credit," "public utility," "shared solar energy facility," and "subscribing customer." It mandates that public utilities interconnect shared solar energy facilities that meet specific criteria, including generating capacity and location within the utility's service territory. The act also outlines the responsibilities of shared solar energy facility owners, including administrative costs and the provision of necessary information to public utilities for billing purposes.

Additionally, the bill sets forth requirements for calculating net energy for subscribing customers, ensuring they receive appropriate on-bill credits based on their share of generated electricity. It grants the Public Service Commission the authority to implement and enforce the act's provisions, including establishing rules for bill credit rates, participation opportunities, and consumer protection. The act is effective immediately upon passage and approval, and it does not affect any rights or duties that were established prior to its enactment.