DISCLAIMER: The following answer is presented for information only, and provides descriptions of information contained in NEPOOL Manual 11 and NEPOOL OP-9, but in no way supersedes those documents. This document also contains references to the NYISO processes. These statements regarding the NYISO market are made from the perspective of ISO-NE and in no way represent NYISO market rules. The NYISO market rules should be referred to for any details on the NYISO market.
The following information describes features of the ISO-NE Day-Ahead Markets (DAM) and Real-Time Markets (RTM) as they apply to External Transactions scheduling and the interaction with the NYISO Day Ahead and Real-Time markets. Market participants have many options on how they may submit transactions in to the various markets. The following interaction of the DAM and RTM between the two Control Areas should be considered when planning that submittal.
The Day-Ahead Markets(DAM) in NYISO and ISO-NE clear entirely independent of each other. Transactions submitted to the NYISO DAM are cleared relative to only the NYISO market. Transactions submitted to the ISO-NE DAM are cleared relative to only the ISO-NE market. There is no comparison of results of any transactions between the ISO-NE DAM and the NYISO DAM. In the ISO-NE market the results of the DAM are financial, creating balancing obligations for the RTM, but do not, in and of themselves, result in transaction scheduling in Real-Time. In the NYISO DAM, due to reliability concerns and software constraints, all cleared DAM transactions are processed as offers of physical energy in real-time. NYISO Virtual Transaction scheduling, within the provisions of the NYISO Services Tariff, are not available at External Nodes.
Transition between Day Ahead Market and Real Time Market
In NYISO, the transactions that cleared the DAM automatically carry forward into the Hour-Ahead Market (HAM) as physical energy transactions for the reasons described above. In the ISO-NE market, transactions that cleared the DAM do not carry forward into the RTM. If a participant wants a RTM transaction to match a DAM obligation, the participant must specifically submit the transaction into the ISO-NE RTM.
Flowing Energy in Real-Time
In order for flow to occur in the Real-Time Market, a transaction must pass one or two checkout processes depending on its submittal time. The first checkout process is the day-before checkout, occurring anytime between 1200 and 1400 the day before the operating day. The term day-before checkout is used rather than day-ahead checkout to clearly separate this process from the clearing or any other aspect of the Day-Ahead Market. In the day-before checkout, the results of the NYISO DAM are compared to only those ISO-NE RTM transactions that were submitted prior to noon the day before the operating day. Transactions that pass this checkout are used in the ISO-NE reliability assessments. The NERC Tag is used as the common identifier and the MW profiles for the transactions in the two markets are compared. This information must match to 'pass' the checkout.