By Christen Smith
VALLEY FORGE, Pa. — The American Wind Energy Association on Thursday said that PJM’s proposal to change how wind and solar capacity values are calculated does not account for the technologies’ performance improvements over the last decade.
After a year of stakeholder discussions, PJM staff will ask the Planning Committee in April to endorse calculations based on effective load-carrying capability (ELCC), which measures the additional load that a group of generators can supply without a reduction in reliability. Jerry Bell, of PJM’s resource adequacy department, presented the Manual 21 changes during the March 7 PC meeting.
PJM’s five-step process for delivery year 2022/23 begins with an average of the ELCCs for each year since 2012/13. The RTO determined that the composite ELCC is 4,181 MW, 21% of the 19,910 MW of nameplate wind and solar capacity projected for 2022/23.
After calculating the ELCC’s for the two generation types separately, PJM then prorated the shares between wind and solar, resulting in capacity factors of 12.3% and 45.1%, respectively. (See “PJM Pushes Change in Wind, Solar Capacity Measurements,” PJM PC/TEAC Briefs: Feb. 7, 2019.)
PJM would assign the ELCCs to existing individual units based on their output during the top 10 daily peak load hours in the 10 most recent delivery years. Future units will get the class average credit unless they request a project-specific calculation.
Representing AWEA, Gabel Associates’ Travis Stewart told the PC that the RTO’s proposal understates the current fleet’s capacity value by giving equal weight to all years in the sample.
Stewart said federal data shows wind capacity factors increased from 30.2% to 42.5% between 2009 and 2016, while solar’s capacity factors increased from 20.8% to 26.8% between 2010 and 2016. PJM’s equal weighting ignores the fact that older, less productive projects represent a small share of the current fleet, AWEA says.
“When PJM attaches an ELCC average to the entire renewable generation fleet, it fails to account for the individual generator’s share,” Stewart said.
The association proposed two options for remedying its concerns:
- Option 1: Find the average ELCC for each renewable project vintage across all historical years, and then calculate the ELCC for the current fleet by weighting according to each vintage’s share of the current fleet.
- Option 2: To account for Option 1’s potential to mask the underlying renewable performance trend, AWEA proposes building a larger dataset by combining each year’s renewable output profile with corresponding load patterns to calculate an average ELCC. The trendline of ELCC change across years could then be used to weight PJM’s results under its current method to recreate what ELCC performance in prior years would have been with the current fleet.
Patricio Rocha Garrido, of PJM’s resource adequacy department, said staff have “some issues” with AWEA’s second option.
“We want to capture the relationship between wind output and load. … Once you start mixing outputs from one year with load shapes from another year, then that relationship gets totally missed,” he said. “You achieve your goal of increasing sample size, but you totally lose that correlation.”
PJM will present a first read of the manual changes at the March 21 Markets and Reliability Committee meeting before seeking an endorsement in April. The discussion will likely rehash stakeholder concerns over the handling of capacity interconnection rights (CIRs). (See related story, Showdown Set on PJM Must-offer Exceptions.)
“We purchased a lot of these CIRs through upgrades. … [PJM is] making a change here; this is not us retiring units,” said John Brodbeck of EDP Renewables. “This is not the good Lord knocking a whole bunch of towers down. This is a decision to rerate units by PJM and that has a different impact than anything else. We don’t like to see our assets taken away.”
PJM’s ELCC formula represents a shift in thinking for the RTO, which had been pushing an alternative method using average values. The new methodology is more representative of the incremental value of adding a new unit to the existing fleet, PJM’s Tom Falin said in February.
The Manual 21 changes include a new section devoted to obtaining, maintaining or losing CIRs, as well as sections devoted to installed capacity calculations and testing requirements.
New rules on testing within temperature bounds will take effect June 1 with rules on simultaneous testing and the ELCC effective for delivery year 2022/23. Wind and solar units losing CIRs would be notified before Jan. 1, 2025.
Notably, the testing window for generators remains June 1 through Aug. 31 after stakeholders expressed concerns over an earlier proposal from PJM to instead start in July. (See “Skepticism of Gen Capability Changes Continues,” PJM Operating Committee Briefs: June 5, 2018.)
PJM wants MRC endorsement by the April meeting so that unforced capacity (UCAP) values for wind and solar can be posted by May 1 for use in the 2022/23 Base Residual Auction in August. They would not affect UCAP values from prior auctions.