Advice Filing - Pacific Power

1 transmission services from the third-party transmission provider. PacifiCorp's
2 recent experience with the Threemile Canyon Wind Farm 1, LLC illustrates the
3 incremental costs that are involved.
4 Threemile Canyon Wind 1, LLC.
5 10. Dalreed is a PacifiCorp load pocket near Arlington, Oregon.
6 PacifiCorp's load at the Dalreed substation ranges from about 44 MW peak during
7 the summer down to less than 2 MW during the winter. PacifiCorp imports energy
8 to Dalreed across BPA transmission under the General Transfer Agreement between
9 Bonneville Power Administration and PacifiCorp (BPA Contract No. DE-MS79-
10 828P90049) dated May 4,1982 (the "BPA GTA"). The BPA GTA makes no provision
11 for energy exports out of the Dalreed load pocket because historically there was no
12 generation in the load pocket requiring export.
13 11. Threemile Canyon Wind I, LLC (Threemile) is a 9.9 MW wind QF that
14 is interconnected with PacifiCorp's Dalreed substation near Arlington. In 2009,
15 PacifiCorp evaluated how much excess generation was likely at Dalreed, based on
16 actual Dalreed 2006-2008 hourly load and an hourly generation forecast provided
17 by Threemile. The study predicted excess generation conditions between 1,020 and
18 1,289 hours per year, involving between 8% and 10.5% of total Threemile output.
19 The study showed likely recurring periods of excess generation during winter
20 months, necessitating the purchase of BPA firm PTP transmission to move excess
21 generation from the Dalreed load pocket to another location on PacifiCorp's system
22 with adequate load to absorb the Threemile output. A graph of the Dalreed load and
23 predicted Threemile generation showing the timing and extent of expected excess
Affidavit of Bruce Griswold 5
in Support of PacifiCorp's Advice No. 11-011