Wednesday, November 14, 2018

Unidentified: MISO to Use Prior Export Limit for Zone 5

By Amanda Durish Cook

CARMEL, Ind. — The Resource Adequacy Subcommittee has allowed MISO to use last year’s capacity export limit for Missouri’s Zone 5 after the RTO could not identify the limit.

MISO recently released zonal capacity import and export limits from this year’s loss-of-load-expectation study but said it could not find transmission constraints or a capacity export limit for Local Resource Zone 5. In its place, the RASC by consent allowed the Loss-of-Load-Expectation Working Group to use last year’s 2,122-MW export limit for the zone in the 2019/20 Planning Resource Auction.

MISO’s capacity export limits determine a local resource zone’s export capability on transmission for the PRA. When MISO cannot determine a transmission limit, it uses a generation-limited transfer study, which simulates further stressing of the transmission system after the RTO hypothetically runs out of generation to dispatch in the zone. The study is meant to discover whether a zone’s first transmission constraint would occur only after all the zone’s generation is dispatched at maximum levels.

Rauch | © RTO Insider

In Missouri’s Zone 5 this year, no constraints were found even after the generation limited transfer study, said Laura Rauch, MISO director of resource adequacy coordination.

“We did run into an issue with Missouri capacity export limit,” Rauch told stakeholders attending a Sept. 12 RASC meeting.

Rauch also said MISO’s current process doesn’t provide for another analysis if it is unable to determine zonal transmission limits after an initial analysis and a generation-limited transfer study. “This is a situation that is not documented in our process,” she said. “We wanted to bring this to the RASC because this is a policy issue.” Rauch said the LOLEWG will begin working on a solution and codifying a new process.

Customized Energy Solutions’ David Sapper asked for more discussion on MISO’s options. He said because the RTO could find no constraint, the zone’s capability is hypothetically unlimited.

“I think it’s worth a round of feedback,” Sapper said.

“For the auction clearing, we do need to input some number, whether that’s 9,999” or another value, Rauch said.

RASC Chair Chris Plante said it was unlikely that imposing a limit as low as 2,000 MW or as high as 9,999 MW would affect auction clearing results.

Sapper pointed out that MISO using the previous year’s limit potentially opens the doors to using other previous capacity auction values. It could become that the “past is not prologue,” he said.

Consumers Energy’s Jeff Beattie asked the room if anyone thought the one-year adoption would violate MISO’s standard to value reliability first. Rauch said that standard does contain language allowing use of historic capacity limits when appropriate.

“Our view of Zone 5 is that there isn’t significant change from last year,” Rauch said.

New CONE values

MISO has also made its annual FERC filing to update its cost of new entry values for the 2019/20 planning year. The RTO’s CONE now ranges from a low of $81,640/MW-year ($223.67/MW-day) in Louisiana and East Texas’ Zone 9 to a high of $89,960/MW-year ($246.47/MW-day) in Missouri’s Zone 5.

“The estimates are down from a year ago, as they were last year, about $2,000 to $3,000 across the board,” MISO adviser Mike Robinson said.

CONE represents the estimated annualized capital cost of constructing a 237-MW nominal capacity combustion turbine plant in different locations in the footprint. MISO uses CONE as the maximum offer and maximum clearing price in its PRAs.

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