ERCOT Reports Software Error Had Resulted In Erroneous Calculation Of Total Potential Exposure (Collateral Metric) For Market Participants
June 5, 2020 Email This Story Copyright 2010-20 EnergyChoiceMatters.com
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ERCOT stated in a market notice that it has identified a software error in its Credit Monitoring and Management (CMM) system that impacted the Total Potential Exposure (TPE) calculation for market participants, with the error occurring with the implementation of Nodal Protocol Revision Request (NPRR) 347, Single Daily Settlement Invoice and Updates to Credit Calculations, including addition of a Minimum Collateral Exposure Component, on November 9, 2012.
ERCOT implemented a software fix on June 4, 2020 to align the Total Potential Exposure (TPE) calculation with NPRR347, as described below.
ERCOT stated in the market notice that, "NPRR347, in relevant part, revised the TPE calculation. TPE sets the amount of Financial Security that a Counter-Party must post with ERCOT to satisfy creditworthiness requirements. TPE incorporates estimates of forward Real-Time, Day-Ahead, and Congestion Revenue Rights (CRR) exposure. Forward market exposure estimates utilize defined variables, including Real-Time Liability (RTL), which are comprised of specified market exposure elements. Real-Time Liability Forward (RTLF), an estimate of Real-Time forward exposure, uses RTL to define a Counter-Party’s potential liability for seven future days. Under NPRR347, a Counter-Party’s RTL is multiplied by 110% if it represents an amount owed to ERCOT, and by 90% if it is a credit to the Counter-Party. The result is then adjusted by 150% in RTLF."
"ERCOT has determined that the 110% and 90% adjustments to RTL have not been included in the RTLF calculation since the implementation of NPRR347. In addition, the 150% RTLF adjustment has not been applied to two RTL components: Real-Time congestion payments/charges for Self-Schedules, and payments/charges for Point-To-Point (PTP) Obligations settled in Real-Time. Because RTL can represent charges or credits, the impact of the errors on RTLF can be either positive or negative," ERCOT stated in the market notice
"The TPE calculation utilizes the maximum of RTLF and a second Real-Time liability estimate, the maximum of Real-Time Liability Extrapolated (RTLE). Therefore, the error may have increased TPE in cases where it incorrectly caused RTLF to exceed the maximum of RTLE, and decreased TPE when the opposite occurred. In short, in some circumstances, the software error either increased or decreased a Counter-Party’s TPE, which may have resulted in more or less collateral being posted with ERCOT than would otherwise have been the case," ERCOT stated in the market notice
"Due to system limitations, ERCOT is unable to quantify the number of instances where an erroneous RTLF determined the TPE for a Counter-Party since the implementation of NPRR347. However, since January 2019, ERCOT estimates that on most days, the total aggregate RTLF, if corrected, would have exceeded the erroneously computed RTLF. Moreover, the maximum of RTLE would likely have exceeded the corrected RTLF on all but one day, indicating that the error impacting RTLF was likely not a material driver of total TPE since January 2019," ERCOT stated in the market notice
ERCOT stated in the market notice that ERCOT plans to discuss this error at the Market Credit Working Group (MCWG) / Credit Work Group (CWG) meeting on June 17, 2020, and at the Technical Advisory Committee (TAC) meeting on June 24, 2020.