Tariff Filing of Green Mountain Power Corporation for Approval of an Energy Storage System Tariff and Tariff Filing of Green Mountain Power Corporation for Approval of a Bring Your Own Device Tariff

Green Mountain Power Corporation (GMP) (plaintiff) was a monopoly distribution utility with exclusive control over the infrastructure that delivered electricity to a Vermont area. GMP applied to the Vermont Public Utility Commission (commission) for the approval of two tariffs. The Energy Storage System (ESS) tariff allowed up to 500 GMP customers per year to lease new ESS systems from GMP. The system consisted of two Tesla batteries and a gateway device installed in a customer’s home. Electricity from the batteries could provide backup power to the home during power outages but could also be used by GMP to reduce demand across the electric grid during peak periods. Under the ESS tariff, participating customers would pay a monthly lease fee of $55 for 120 months or a one-time lease fee of $5,500. Either way, the lease amount was less than the system cost, meaning that GMP was subsidizing the equipment. Alongside the ESS tariff, GMP proposed the Bring Your Own Device (BYOD) tariff, which would provide an upfront payment to GMP customers who purchased and installed battery-storage systems from third parties and allowed GMP to access the systems during peak periods. The Vermont Department of Public Service (department) (defendant) opposed the proposed tariffs, arguing that they were not just and reasonable because they (1) placed a disproportionate risk on nonparticipating customers who would ultimately fund GMP’s investments and incentives and (2) unfairly stifled competition from the private sector. It recommended an alternative single pay-for-performance tariff, which would provide compensation to a customer only when energy was used from private batteries during peak demand.