CARMEL, Ind. — MISO says it will look to make improvements to the capacity testing process after sifting through results from its generators and discovering errors.
The RTO received more than 1,800 submittals from approximately 140 generation operators by the Oct. 31 deadline for its generation verification test capacity (GVTC) process. It requires generation owners to test the capability of their units annually to determine maximum capacity to help calculate MISO’s resource adequacy.
At the Resource Adequacy Subcommittee’s meeting Tuesday, MISO Manager of Capacity Market Administration Eric Thoms said the RTO would reach out to about 40 generation owners this month to discuss correcting possible errors in the submittals in time for the 2020/21 Planning Resource Auction.
Some stakeholders asked how MISO had determined errors had been made in the first place.
“It wouldn’t be obvious to me that we’ve even made errors,” MidAmerican Energy’s Greg Schaefer said.
Thoms said MISO performed a quality and validation review at the behest of its Independent Market Monitor. He said the likely errors are centered on temperature corrections for cooling water and air temperature, generator polarity data, and “misinterpretations” of some of the fields on the survey.
RASC liaison Patrick Brown said that over the next year, the RTO will investigate potential GVTC process improvements to “increase the quality of data being submitted and lesson the burden of MISO’s review.”
“We’re not trying to eat the elephant all at once,” Brown said of working in improvements.
Stakeholders Remain Critical of Capacity Deliverability Remedy
MISO remains committed to tightening capacity deliverability requirements using the same method it proposed in October, but some stakeholders are voicing concerns over reduced capacity credits issued to wind resources.
The RTO has said it will use an intermittent resource’s transmission service request value to set its maximum historical output for the average capacity factor, which will likely reduce a resource’s unforced capacity values and stands to reduce capacity credits. It would only apply the solution to its intermittent resources, citing increasing wind curtailments in the footprint. (See “MISO Pushes Back Deliverability Requirements,” MISO RASC Briefs: Oct. 9, 2019.)
MISO’s Darrin Landstrom said the move will “improve the expectation of generators required to deliver capacity to load.”
“Under the current process, an intermittent resource that is not fully deliverable could acquire capacity credit with the same equality as an intermittent resource that is fully deliverable. Revising capacity accreditation calculations to factor in studied levels of deliverability may incentivize intermittent resources to obtain more deliverability if necessary and/or improve the confidence that capacity is being accredited in a method that more closely aligns with deliverability levels,” MISO said.
The Monitor has argued for more than a year that the RTO doesn’t properly account for capacity deliverability because its loss-of-load expectation (LOLE) study assumes that all capacity resources are fully deliverable on an installed capacity (ICAP) basis. However, it also allows resources to demonstrate deliverability only up to the unforced capacity (UCAP) levels, which tend to be about 5 to 10% below full ICAP levels. The Monitor thinks it should assess deliverability for all capacity resources based on full ICAP.
Madison Gas and Electric’s Megan Wisersky said MISO’s proposal may be expensive in that more capacity resources or more transmission capacity will be required to meet peak loads.
“Are we merely trying to jack up the transmission we’re building, increasing costs to our customers?” she asked.
Landstrom said the proposal might leave some of the wind fleet’s effective load carrying capability (ELCC) unassigned. He said the unassigned ELCC might be applied to resources that have secured full deliverability through transmission service. However, MISO may run into problems if it gives a resource more capacity credit than the reliability, including the issue of “how to slice and divide the ELCC pie.” MISO annually calculates a system-level ELCC, which is currently 15.7% of the MISO wind fleet’s registered maximum capacity.
IMM Michael Chiasson also pointed out that there are few benefits to purchasing transmission service for 100% deliverability. He said it’s possible to achieve zonal resource credit requirements “well under” full deliverability.
“We have some homework to do,” Brown said before closing the discussion. He said MISO may need to delay release of its design concept until February and promised another presentation in January. “In my mind, we have a lot of open questions, and I’ll take that, on behalf of MISO staff.”
— Amanda Durish Cook
