Appeal of PRS Action NPRR 351, Calculate and Post Projected Non-Binding LMPs for the Next 15 Minutes...
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Transcript of Appeal of PRS Action NPRR 351, Calculate and Post Projected Non-Binding LMPs for the Next 15 Minutes...
Appeal of PRS ActionNPRR 351, Calculate and Post Projected Non-Binding LMPs for the Next 15 Minutes
Floyd Trefny
Texas Steel Companies
Appeal of PRS Action On October 20, 2011, PRS tabled NPRR351, Calculate and
Post Projected Non-Binding LMPs for the Next 15 Minutes, delaying action to Approve the NPRR Motion to table passed by a very narrow margin
PRS and WMS desire to hold workshops on the full scope of “look ahead SCED” prior to consideration of NPRR 351 First workshop now scheduled for December 5, 2011
NPRR 351 does not implement any functionality of “look ahead SCED” Posts “non-binding” projected LMPs on the MIS
TAC is requested to instruct PRS to either approve or reject NPRR 351 at their next scheduled meeting in November 2011 without further delay
ERCOT Implementation of NPRR 351
ERCOT intends to implement NPRR 351 using program modules that could be used in the future to support a fully integrated “look ahead SCED”
Program modules would be built to produce “Non-Binding” LMPs as originally called for in NPRR 351
The ERCOT modified NPRR 351 would also add additional posting and information that could be used to study the ability of “look ahead SCED” to project future grid conditions
Will provide Base Point projections for up to an hour into the future via the MIS Certified Area
Proposed Scope Of Real-Time Dispatch (RTD)Summer 2012*
Current Production SCED
Real-Time Dispatch (RTD)
Current SCED Inputs
Additional “Look Ahead”Inputs
Binding MW Dispatch & Binding Prices for SCED interval T
Advisory MW Dispatch & Advisory Prices (LMP only) for SCED interval T+5, …T+60
ICCP & MIS
MIS
* - Slide from ERCOT presentation on Implementation of NPRR 351, October 12, 2011
Funding Approved for NPPR 351
At PRS, ERCOT stated, as part of the Impact Analysis discussion, that funding of NPRR 351 would come from the 2012 project budget already approved by the Board Implementation would build the modules for RT
Dispatch of “look ahead” SCED Initial capital cost of $690-$790k
An additional $290k over the original line item of $500k may be needed from the project budget
ERCOT estimates that it will take up to six months to implement
Urgency Is Needed Language of the NPPR is very broad and not
likely to be changed as a result of WMS and PRS Workshops Likely there will be many more workshops before any consensus
is built on the future features of ‘look ahead” SCED Holding up posting of prices pending detail development of Real
Time co-optimization of Ancillary Services, Real Time unit commitment, Outage anticipation, and other features is not needed to move forward
REPs who plan “time of use” residential products need assurances ERCOT will implement the non-binding postings for summer 2012
Urgency Is Needed (concluded)
Prospects for increasing the Market Offer Cap and/or adding floors to energy offers as part of the Resource Adequacy issues is likely However, without also giving the consumers the
opportunity to reject the prices by limiting consumption is patently unfair to consumers
ERCOT has on several occasions outlined the concepts of look ahead SCED at WMS ERCOT provided examples of look ahead RT Dispatch with
Ramp constraints
TAC Action
ERCOT’s plan to implement “look ahead SCED” in phases is a good idea Big bang approaches usually bring surprises and unintended
consequences
Building a parallel calculation alongside the current 5 minute SCED, gives opportunity to compare operations scenarios and effects on prices with a “study” look ahead SCED ERCOT staff urged PRS to approve the NPRR as is
TAC should approve a motion to instruct PRS to either approve or reject NPRR 351 at their next scheduled meeting in November 2011
TAC Motion
TAC encourages WMS and PRS to continue discussions with ERCOT on the details of the “look ahead” SCED through workshops, special meetings, or other means.
TAC instructs PRS to either approve or reject NPRR 351 at their next scheduled meeting on November 17, 2011 and report back to TAC at the December 1, 2011 TAC meeting.
Appendix
Protocol Language of NPRR 351
Protocol Language of NPRR 351
6.5.7.3 Security Constrained Economic Dispatch(6) For each SCED process, in addition to the binding Base Points and LMPs,
ERCOT shall calculate a non-binding projection of the Base Points and Resource Node LMPs, Hub LMPs and Load Zone LMPs at a frequency of every five minutes for at least 15 minutes into the future based on the same inputs to the SCED process as described in this Section, except that the Resource’s HDL and LDL and the total generation requirement will be as estimated at future intervals. The Resource’s HDL and LDL will be calculated for each interval of the projection based on the ramp rate capability over the study period. ERCOT shall estimate the projected total generation requirement by calculating a Load forecast for the study period. ERCOT shall post the projected non-binding Base Points for each Resource for each interval study period on the MIS Certified Area and the projected non-binding LMPs for Resource Nodes, Hub LMPs and Load Zone LMPs on the MIS Public Area pursuant to Section 6.3.2, Activities for Real-Time Operations.