This Nodal Protocol Revision Request (NPRR) removes the rating requirement in the current definition for Electrically Similar Settlement Points and introduces a daily public report to post the heuristic pricing associations for Day-Ahead Market (DAM) and Real-Time Market (RTM) price calculations.
In the interest of improving the consistency of modeling and accurately valuing congestion in the ERCOT markets, this NPRR offers to improve the definition of Electrically Similar Settlement Points and improve the market transparency of Settlement Points that are subject to predefined pricing heuristic logic.
Regarding the Electrically Similar Settlement Points definition, Settlement Points connected by Transmission Elements that are "electrically close" should not have different prices due to congestion and hence should be marked as Electrically Similar Settlement Points. The current Protocol definition specifies that Settlement Points designated to be Electrically Similar Settlement Points be mapped to the same electrical location in a market model or mapped to locations that are connected by a Transmission Element modeled with a reactance of less than 0.0005 per unit and an MVA rating of more than 9000 MVA. The intent of the current Protocol definition is to allow the use of either a reactance value or MVA limit sufficient to achieve the mapping of Electrical Similar Settlement Points regardless of the source used to construct the consistent market model used across ERCOT market systems (i.e., Market Management System (MMS) and Congestion Revenue Right (CRR) system). ERCOT has determined that the use of MVA ratings in excess of 9000 MVA is no longer necessary and that the use of a Transmission Element modeled with a reactance less than or equal to 0.0005 per unit is sufficient to assure consistency in the market model across the ERCOT market systems. Consequently, ERCOT proposes the removal of the Protocol provision related to the 9000 MVA rating.
Regarding posting heuristic pricing logic information, ERCOT offers to post the heuristic pricing associations on a daily basis that are used in the market solutions to support paragraph (9) of Section 4.5.1, DAM Clearing Process, and Section 6.6.1, Real-Time Settlement Point Prices. With this posting, the market will better understand the methodology and values of the published prices.