Pastoria combined-cycle plant in California undergoes 50 MW in upgrades

In an Oct. 9 filing, Southern California Edison submitted to the Federal Energy Regulatory Commission a copy of a Large Generator Interconnection Agreement covering a 50-MW uprate, to a total of 800 MW, for Calpine Corp.‘s (NYSE: CPN) Pastoria Energy Facility LLC plant.

The new LGIA includes the existing 750 MW combined-cycle facility and a 50 MW increase in capacity (under California ISO queue #911).

The plant consists of three gas turbine generators each rated at 234 MVA, one steam turbine generator rated at 234 MVA, and one steam turbine generator rated at 105 MVA. The individual generator output of the existing 750 MW Pastoria Energy Facility was identified to be (i) 166.52 MW at 63 degrees F for each of the three 234 MVA gas turbine generators as limited by the turbines (ii) 181.999 MW for the 234 MVA steam turbine generator, and (iii) 89.64 MW for the 105 MVA steam turbine generator.

Two gas turbine generators are paired together with the 234 MVA steam turbine generator (Power Block 1) for a collective gross output of 515.039 MW. The remaining gas turbine generator is paired with the 105 MVA steam turbine generator (Power Block 2) for a collective gross output of 256.16 MW.

The maximum plant auxilary loads for Power Block 1 is identified to be 9.5 MW with a corresponding 8.0 MVAR requirement resulting in a collective net output of 505.539 MW. The maximum plant auxilary loads for Power Block 2 is identified to be 5.0 MW with a corresponding 3.9 MVAR requirement resulting in a collective net output of 251.16 MW. The total plant gross MW output is therefore 771.199 MW and the total plant net output (gross for Power Block 1 and 2 combined less auxiliary loads for Power Block 1 and 2 combined) is 756.699 MW at the high-side of the main transformer banks. Interconnection service is currently limited not to exeed 750 MW at the Point of Interconnection.

Pastoria Energy has implemented upgrades to both of the Power Block 1 gas turbines. The upgrades involved replacement of fuel nozzles, buckets, and blades (refered to as the “.04 Upgrade” from General Electric 7FA version .03 to .04) thereby increasing the respective output from 166.52 MW to 175 MW at 63 degrees F. Operation at low ambient temperature will also allow the two gas turbine to further increase output to a value of 191 MW each at 35 degrees F and will enable the corresponding steam turbine to increase its output to 182 MW for a gross output of 564 MW for Power Block 1. Power Block 2 is presently capable of generating 267 MW at 35 degrees F.

Collectively, the “.04 Upgrade” has enabled the total gross plant output to be presently 831 MW at 35 degrees F. Auxiliary loads are about 15 MW resulting in the net plant output being around 816 MW at 35 degrees F as measured at the high side of the main transformer banks.

As part of the interconnection request submitted in Queue Cluster 5, Interconnection Service will be limited to not exceed 800 MW at the Point of Interconnection. Given the relatively short generation tie line, this limitation is applicable to the high side of the main transformer banks.

Said the Calpine website about this plant: “The Pastoria Energy Facility, located on the Tejon Ranch just south of Bakersfield, California, began commercial operation of its Phase I in May 2005 and Phase II in July 2005. Calpine Construction Plus performed all general contractor functions, including management of all activities between contractors, engineers and equipment suppliers.”

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.