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Non-Dispatchable
Resources and EIS
Market
Carrie Simpson
May 30, 2013
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Agenda
•
Overview of EIS Market Design for Non-Dispatchable
Resources
•
Common EIS Market Practices
•
Staff Recommendation
•
Appendix: Changes coming for Marketplace
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Section 1
OVERVIEW
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EIS Market and Intermittent Resources
•
SPP dispatches Non-Dispatchable Resources to the echo of the
resource output every 5 minutes
–
Wind farms using “Intermittent” status in the resource plan are considered
a Non-Dispatchable Resource (NDR)

–
No economic evaluation is used by the Market for dispatching NDRs
If congestion develops on the system that requires curtailment of the
NDRs, SPP uses two methods:
1.
2.
Systematic Curtailment through the Market System and Curtailment
Adjustment Tool based on transmission priority
– New as of March 19, 2013 as a result of three years of stakeholder
processes and FERC approval of PRR 240
» More resources will be added on October 15, 2013
Manual Curtailment through Reliability Directives using shift factors
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Systematic NDR Curtailment (PRR 240/242)
•
During non-congested intervals, NDRs are dispatched to
persistence (echo of output)
•
For resources under the systematic logic:
–
In the congestion management process, the SPP Curtailment
Adjustment Tool (CAT) includes the unscheduled portion of
the output from NDRs in curtailment calculations

Assigns a pro rata relief obligation similar to obligations assigned to other
non-firm impacts calculated by SPP CAT and NERC IDC.

GLDF of the unscheduled portion of a NDR is based upon the GSF of the
Resource to the constraint and the host BA LSF associated with the constraint.
– If GLDF is lower than the cutoff threshold used for interchange
transactions no curtailment obligation will be assigned
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Systematic NDR Curtailment (PRR 240/242)
•
For NDRs with firm transmission service for the full
output of the resource:
–
•
Any unscheduled output will be assigned a virtual
schedule with firm transmission priority (PRR 242
change)
For resource without firm transmission service for the
full output of the resource:
–
Any unscheduled output will be assigned a virtual
schedule with a non-firm transmission priority of NH2
(in original PRR 211-240 design)
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EIS Market and Intermittent Resources
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MPs may choose to use “Available” status for intermittent resources in
the EIS Market, which dispatches based on price and ramp rates
–
Allows resource to be included in the Market solution and set price
–
SPP expects the resource to follow dispatch instructions

If the resource does not follow the dispatch instruction it will be subject to URD charges
– In addition, adds error to Market solution and causes burden on host BA
–
Reliability Coordinator can still manually curtail a resource in “Available”
status via a directive
–
Must contact SPP Market Operations before pursuing this option to
walkthrough business practices

EIS Market does not use a wind forecast and MPs cannot update resource
maxes inside an operating hour systematically
– Requires communication to the Market Operator by the Market Participant to
update the resource max of the resource in real-time
–
When using Available status, PRR 240/242 logic does not apply
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Section 2
COMMON EIS MARKET PRACTICES
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MP Common Practices
•
Many intermittent resources using “Intermittent” status
choose to follow the LIP prices for determining when to
curtail output
–
–
Example:

Wind farm operating at 100MW and sees a price of -$40/MW

Wind farm turns off to 0MW
Reasons:

Market Participants are trying to manage price exposure

Provide relief to the market using the price as a signal of the
problem
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Challenges with Common Practices
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Challenges with this practice:
1. Creates oscillation in constraint management and
pricing in the EIS Market solution

Market solution is always 10 minutes behind real-time
Negative LIP Wind farm turns off Constraint relieved
 Positive LIP  Wind farm turns on  Constraint
violated Negative LIP process starts over again
2. Causes Reserve Sharing Events for host BA
 SPP Criteria 6.4.2 requires a BA to report the a loss of
generating output of 50 MW or more to the Reserve Sharing
Group.
 Burdens the host BA for regulation and back-filling the lost
generation
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Section 3
SPP STAFF RECOMMENDATION
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Staff Recommendation
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If an MP prefers to respond to prices in the EIS
Market SPP recommends:
–
–
Use “Intermittent” status but only respond in
increments of less than 50MW

Causes less price and constraint oscillation in the Market

Prevents host BA from calling RSG event

Limits regulation burden on host BA
Or, use “Available” status in order be apart of the
market solution and contact with Market Operations
to work through the business practices required
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Questions
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Marketplace Changes
APPENDIX
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Marketplace Improvements
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Marketplace enables Intermittent Resources more
flexibility for participation in the market
•
Allows Intermittent Resources to be included in the
Market solution, if registered as Dispatchable Variable
Energy Resources
–
•
Uses the offer curve, ramp rate details, output, and
forecast to help determine the optimal dispatch for the
resource and the market, together
SPP continues to look for way to apply manual
curtailments more efficiently
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Marketplace and Intermittent Resources
•
Variable Energy Resource (VER)
–
–
A Resource powered solely by wind, solar energy, runof-river hydro or other unpredictable fuel source that is
beyond the control of the resource operator.

Dispatchable Variable Energy Resource (DVER):

– A Variable Energy Resource that is capable of being
incrementally dispatched down by SPP
– Eligible to offer Regulation-Down, if qualified
Non-Dispatchable Variable Energy Resource (NDVER):
– A Variable Energy Resource that is not capable of being
incrementally dispatched down by SPP
All VERs must register as a Dispatchable VER except for VERs with
an interconnection agreement executed prior to May 21, 2011 that
were commerically operational before October 15, 2012.
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Dispatch of VERs in Marketplace
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In the Real-Time Balancing Market (RTBM), persistence will
be used (echo of actual SCADA output) when there is no
congestion on the system
–
For DVERS:

When there is congestion on the system:
– SPP will use the offer curve of the DVER and Market Participants
will be a sent a follow signal to lower output

When congestion is over:
– SPP will dispatch DVER up at the submitted ramp rate until max
limit (lesser of submitted max limit or SPP’s output forecast) is
reached
–
For NDVERs

If SPP needs a NDVER to curtail, the SPP RC will issue a Directive/OOME
to curtail the resource down similar to the EIS Market manual process
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