Inverters Batteries

FERC confirms QF self-certification for a hybrid photo voltaic and battery undertaking, prompting dissent from Commissioner Danly – JD Supra

On December 17, 2021, FERC confirmed self-certification for the Shields Valley Solar Facility (“Shields Valley”), a hybrid solar and battery project, under the Public Utility Regulatory Policies Act of 1978 (“PURPA”) to rely on inverters to to limit its net electricity generation capacity. In doing so, FERC reinforced its finding in its Broadview Solar Renewal Order that a QF owner can use the MW net capacity at the connection point, accounting for inverter losses and other power generation components, to determine if a facility will meet the 80 MW legal maximum for the QF -Status. Commissioner James Danly wrote separately in dissenting form setting out his view that Shields Valley clearly exceeds the statutory capacity limit for a QF.

The Shields Valley project will consist of 380,952 solar panels for a total DC nameplate capacity of 160MW and a battery storage system with an expected capacity of 80MW on the DC side of the solar array, along with 27 inverters that will result in a maximum net AC generating capacity to the connection point of 80MW – this is the upper limit for a facility to be considered QF under PURPA. Interconnected utility NorthWestern Corporation d/b/a NorthWestern Energy (“NorthWestern”) filed a protest, arguing that Shields Valley does not qualify as a QF because the solar and battery plants are separate power generation plants with capabilities that result in power generation capacity substantially larger than the 80 MW QF size limit, even under the FERC analysis used in the Broadway Solar contracts (see WER issue of March 25, 2021).

FERC dismissed NorthWestern's arguments as a collateral attack on Broadview Solar, confirming that plant configurations where the solar panels, battery storage system, and inverters combined have a maximum net AC production capacity of 80 MW are eligible for QF certification as a small power plant in come question. FERC determined that Shields Valley can only supply a maximum of 80MW of AC power to NorthWestern's system at any one time and therefore, in accordance with Broadview Solar, Shields Valley's power generation capacity cannot and will not exceed 80MW. Broadview Solar is appealing to the United States Court of Appeals for the District of Columbia Circuit (see D.C. Circuit Nos. 21-1126, 21-1136, 21-1142, 21-1149, 21-1175).

Commissioner Danly wrote separately to reinforce his view that the actual generating capacity of the Shields Valley plant is irrelevant not only because the plant is designed not to be able to supply more than 80MW to its interconnector at any one time. Danly expressed the same position in his dissent in Broadview Solar, but also noted here that despite NorthWestern's arguments to the contrary, he would find that batteries and other storage devices do not "produce" electricity and therefore should not be counted in the QF's size limit.

A copy of the order can be found here.

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