NOTICE DATE: September 4, 2009
NOTICE TYPE: W-A090409-01 – Operations
SHORT DESCRIPTION: Procurement issue with
Non-Spinning Reserve Service (NSRS) Resources in Replacement Reserve Service
(RPRS) clearing
INTENDED AUDIENCE: QSEs and Resource Entities
DAY AFFECTED: See below
LONG DESCRIPTION: On June 12, 2007, ERCOT
implemented modified software code enabling the Replacement Reserve Service
(RPRS) engine to include consideration of Resources with Non-Spinning Reserve
Service (NSRS) capacity commitments. To accomplish this, the code designates
any Resource identified in its Resource Plan as committed for NSRS as
“On-line.” This On-line indication prevents the RPRS engine from
procuring the Resource for the NSRS-indicated intervals.
ERCOT has
identified an issue with the code that causes Resources transitioning from an
NSRS-committed interval to an interval with unit status of
“Off-line” and “available” to be considered
RPRS-eligible. Rather than recognizing the Resource as Off-line, the RPRS
engine assumes the Resource is On-line and that it can extend the run time of
the Resource without incurring the Resource’s start-up cost, therefore
not considering the start-up portion of the bid in RPRS clearing. This could
potentially result in under-pricing the RPRS Market Clearing Price for Capacity
(MCPC) by artificially displacing more economic alternate bids.
Off-line
Resources procured for RPRS are kept whole to their start-up bids in
settlement. The ERCOT Settlement system identifies their Off-line status via
breaker status and makes an ex-post payment adjustment to the QSE for Resource
start-up and actual run time.
ERCOT is
investigating a solution to this issue and will update this Notice as more
information becomes available.
CONTACT: If you have any questions, please contact your
ERCOT Account Manager. You may also call the general ERCOT Client Services phone
number at (512) 248-3900 or contact ERCOT Client Services via e-mail at [log in to unmask].
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