Daylight Saving Time ends Sunday; fall back to Eastern Standard Time at 2 a.m.

New England will return to Eastern Standard Time (EST) on Sunday, November 5, when, at 2:00 a.m., clocks must be set back one hour to 1:00 a.m. Each of ISO New England’s market applications is unique and will function differently during this transition. Here are the things market participants need to know to prepare.

1. Bids and offers that use uploads and downloads for the eMarket application follow ISO 8601 Date and Time format for XML submittals. This is explained in section 3.1.2 of the eMarket Data Exchange Specification document posted on the ISO website.

The transition will cover 2023-11-05T00:00:00–04:00 through 2023-11-05T23:00:00–05:00. For example: the time (or hour) is represented in the format below. Note that the DateTime format includes the time zone indicator and the example shows time in Eastern Standard Time.

time=”2023-11-05T00:00:00-04:00″
time=”2023-11-05T01:00:00-04:00″
time=”2023-11-05T01:00:00-05:00″ (extra hour)
time=”2023-11-05T02:00:00-05:00″
—
—
time=”2023-11-05T22:00:00-05:00″
time=”2023-11-05T23:00:00-05:00″

2. Asset telemetry, hourly resource availability uploads/downloads via DRMUI application must submit the extra hour as given below.

Greenwich Mean Time (GMT) time format upload/download

The transition will cover 2023-11-05T00:00:00–04:00 through 2023-11-05T23:00:00–05:00. For example:

2023-11-05T04:00:00Z (first five-minute interval)
….
2023-11-05T05:00:00Z
….
2023-11-05T06:00:00Z
….
2023-11-05T07:00:00Z
….
2023-11-05T03:55:00Z
….
2023-11-05T04:55:00Z (last five-minute interval of the day)

Eastern Standard Time for upload/download

The transition will cover 2023-11-05, 00:00:00–04:00 through 2023-11-05, 23:55:00–05:00. For example:

2023-11-05 00:00:00–04:00 (first five-minute interval) (starts with Eastern Daylight Time with 4 hours offset)
….
2023-11-05 01:05:00–04:00
….
2023-11-05 01:50:00–04:00
….
2023-11-05 01:55:00–04:00
….
2023-11-05 01:00:00–05:00 (fall back by an hour and goes to Eastern Standard Time with 5 hours offset)
….
2023-11-05 01:05:00–05:00
….
2023-11-05 01:10:00–05:00
….
2023-11-05 02:00:00–05:00
….
2023-11-05 03:00:00–05:00
….
2023-11-05 04:00:00–05:00
….
2023-11-05 05:00:00–05:00
….
….
….
2023-11-05 23:55:00–05:00 (last interval for the day)

3. Internal bilateral transactions and any meter readings that use uploads and downloads for the SMS application must have the extra hour represented as 2* (that is, “2” followed by an asterisk). The Contract Upload File Formats, the Internal Bilateral Download, and the SMD Metering Upload File Format documents located on the ISO New England website contain required formatting information.

4. MIS reports will present the extra hour as 02X.

5. Lastly, NEXTT and OATI’s eTag system handle the time change differently. NEXTT UI displays date/time in America/New_York time zone, while OATI eTag allows user to set the time zone (for example, EDT, or EST). NEXTT displays the extra hour automatically in the market user interface, labeled as “02X.” NEXTT file upload/download and programmatic interface use GMT datetime, which is not subject to any EDT/EST change. Examples of a NEXXT transaction are shown below. In general, eTags should be created in Eastern Daylight Time (EDT) and cover 25 hours (11/05/2023 00:00 – 11/06/2023 01:00). However, if the transaction begins after the time change has occurred, create the eTag in EST and create the schedule in the normal manner.

1. File upload/programmatic interface: NEXTT schema uses standard GMT date time, no special DST/EST expression (like repeating hour).

<TRANSACTION xmlns=“http://www.iso-ne.com/2018/nextt“xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance“>

    …

<RT_DETAIL>

<RT_TRANSACTION_TYPE>SELF SCHEDULED</RT_TRANSACTION_TYPE>

<RT_INTERVALS>

<RT_INTERVAL>

<INTERVAL_BEGIN>2023-11-05T04:00:00Z</INTERVAL_BEGIN>

<INTERVAL_END>2023-11-05T05:00:00Z</INTERVAL_END>

<BID_MW>100</BID_MW>

<BID_PRICE xsi:nil=“true”/>

</RT_INTERVAL>

<RT_INTERVAL>

<INTERVAL_BEGIN>2023-11-05T05:00:00Z</INTERVAL_BEGIN>

<INTERVAL_END>2023-11-05T06:00:00Z</INTERVAL_END>

<BID_MW>110</BID_MW>

<BID_PRICE xsi:nil=“true”/>

</RT_INTERVAL>

<RT_INTERVAL>

<INTERVAL_BEGIN>2023-11-05T06:00:00Z</INTERVAL_BEGIN>

<INTERVAL_END>2023-11-05T07:00:00Z</INTERVAL_END>

<BID_MW>110</BID_MW>

<BID_PRICE xsi:nil=“true”/>

</RT_INTERVAL>

</RT_INTERVALS>

…

</RT_DETAIL>

</TRANSACTION>

2. NEXTT UI: Date hours are displayed in America/New_York time zone (may differ from customer local time zone). The repeat hour is labeled as 02X:

Additional information and NEXTT file format examples are found in the Upload and Download File Format Protocols document on the ISO New England website. All market participants are encouraged to test their upload files for November 5, 2023, in the SMD Sandbox.

If you have questions on the information above, contact Participant Support and Solutions at 413-540-4220 or AskISO@iso-ne.com.