PacifiCorp seeks Oregon approvals for Stone House solar measure

MidAmerican Energy Holdings (MEH) subsidiary PacifiCorp is asking Oregon regulatory approval for a special conversion standard for a solar project of less than 10 MW.

PacifiCorp and Stone House Solar LLC have asked the Oregon Public Utility Commission for some leeway in calculating the nameplate capacity of solar photovoltaic under an Oregon standard.

The Oregon PUC is expected to take the matter up at an Oct. 28 meeting.

By 2020, the utility is required to own or contract for 8.7 MW alternating (AC) of capacity and output of qualifying solar PV. So PacifiCorp issued a request for proposals (RFP) earlier this year for suitable projects that could be online by the end of 2014.

It selected Stone House, which is a roughly 7 MW-DC solar project located in Christmas Valley, Ore. PacifiCorp is acquiring the output of the project through a power purchase agreement (PPA).

ORS 757.370 limits the nameplate generating capacity of any single solar PV project used to comply with the solar capacity standard to 5 MW-AC.

An additional state standard specifies that the system’s nameplate generating capacity for purposes of meeting the solar capacity standard must be measured on the AC side of the system’s inverter. OAR 860-084-0040(2) further directs that a system’s nameplate capacity, reported in direct current (DC), be converted to an AC equivalent using a conversion of 85% of the manufacturer’s nameplate capacity.

PacifiCorp and Stone House seek a waiver of the 85% conversion standard to meet the 5 MW (AC) limit. Waiver of the rule will allow the solar project to operate economically while never exceeding its output limit “as measured on the AC side of the inverter.”

PacifiCorp and Stone House believe that the project is optimally designed when 5 MW (AC) inverters are installed in conjunction with 7 MW (DC) of panels, the applicants said in a PUC filing.

The PUC staff has recommended that the commission approve the PacifiCorp waiver request. The case involves Docket No, UM 1538.

PacifiCorp is part of MidAmerican, which is part of the Berkshire Hathaway (NYSE:BRK-A, BRK-B) stable of companies.

About Wayne Barber 4201 Articles
Wayne Barber, Chief Analyst for the GenerationHub, has been covering power generation, energy and natural resources issues at national publications for more than 20 years. Prior to joining PennWell he was editor of Generation Markets Week at SNL Financial for nine years. He has also worked as a business journalist at both McGraw-Hill and Financial Times Energy. Wayne also worked as a newspaper reporter for several years. During his career has visited nuclear reactors and coal mines as well as coal and natural gas power plants. Wayne can be reached at