slide1
Download
Skip this Video
Download Presentation
July 11, 2012 | NEPOOL markets committee

Loading in 2 Seconds...

play fullscreen
1 / 26

July 11, 2012 | NEPOOL markets committee - PowerPoint PPT Presentation


  • 97 Views
  • Uploaded on

July 11, 2012 | NEPOOL markets committee. Jonathan Lowell. Principal analyst | market development. Improving the ISO’s Ability to Operate Reliably, Produce Efficient Outcomes, and Reduce Avoidable Curtailments of Wind Resources. Wind Real-Time Dispatch. The Problem.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' July 11, 2012 | NEPOOL markets committee' - augustus-moser


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1
July 11, 2012 | NEPOOL markets committee

Jonathan Lowell

Principal analyst | market development

Improving the ISO’s Ability to Operate Reliably, Produce Efficient Outcomes, and Reduce Avoidable Curtailments of Wind Resources

Wind Real-Time Dispatch

the problem
The Problem
  • The system faces more frequent localized congestion as wind penetration increases
  • Today, this congestion must be handled manually through curtailment instructions
    • To ensure reliability, system operators must take a conservative approach. Can’t risk operating “too close to the edge”.
  • Manual curtailments do not result in price separation
    • Wind resources and other Intermittent resources are “non-dispatchable”
    • Unit Dispatch Software (UDS) is unable to manage congestion by sending dispatch instructions
    • Creates local economic incentives to maximize output when reliability requires reduced output
    • LMPs are inconsistent with “dispatch” decisions to curtail zero-price resources
wind rt dispatch where are we
Wind RT Dispatch – Where Are We?
  • Past MC presentations (see appendix) have described the shortcomings of existing practice, and the ISO’s proposal to provide a “Do Not Exceed” dispatch instruction to dispatchable wind resources.
  • This background information has not changed, and has been discussed several times with the Committee
    • Not the focus for today, but happy to respond to questions
  • Today’s presentation will focus on the principles behind the DNE dispatch and how it will impact LMPs
dne dispatch
DNE Dispatch
  • Dispatchable wind resources will receive a DNE dispatch instruction that reflects:
    • current and forecast wind conditions
    • wind plant economic offers and operating status
    • transmission operating limits and system conditions
    • offers and operating status of non-wind plants
  • Goals of the Wind DNE Dispatch
    • Ensure reliable operation
    • Improve utilization of transmission facilities and minimize curtailments
    • Create prices and incentives consistent with efficient market outcomes (lowest production cost)
    • Enhance operators ability to manage the system during rapidly changing weather conditions
dne dispatch principles
DNE Dispatch Principles
  • A wind resource may operate freely between 0 MW and the DNE limit, as wind conditions allow
  • Must not exceed the DNE limit
  • ISO will use telemetry from the plant and the new wind short term forecast system to produce a high confidence “expected wind generation” for the next dispatch interval
  • If a plant’s expected generation > DNE limit:
    • The plant is being prevented from producing its full potential output
    • Under these conditions, the plant would be eligible to set price
  • If expected generation <= DNE limit, the plant is not constrained by the dispatch, and would not be eligible to set price
dne dispatch conceptual examples
DNE Dispatch – Conceptual Examples

Assume a 150 MW radial line with:

  • 100 MW wind plant offered at $0/MWH
  • 100 MW non-wind resource offered at $20/MWH
  • $35/MWH LMP where the line connects to the meshed grid
  • With no wind:
    • Exp wind = 0 MW, DNE = 50 MW
    • Non-wind DDP = 100 MW
    • LMP = $35
  • With 50% wind
    • Exp wind = 50 MW, DNE = 50 MW
    • Non-wind DDP = 100 MW
    • LMP = $35/MWH
  • With 75% wind
    • Exp wind = 75 MW, DNE = 75 MW
    • Non-wind DDP = 75 MW
    • LMP = $20/MWH
  • With optimal wind:
    • Exp wind = 100 MW, DNE = 100 MW
    • Non-wind DDP = 50 MW
    • LMP = $20/MWH

Note – to provide clarity in the illustration of DNE dispatch principles, examples ignore some of the more complex pricing constraints in the LMP calculator

dne dispatch conceptual examples1
DNE Dispatch – Conceptual Examples

Assume a 100 MW radial line with:

  • 100 MW wind plant offered at $0/MWH
  • 100 MW non-wind resource offered at $20/MWH
  • $35/MWH LMP where the line connects to the meshed grid
  • With no wind:
    • Exp wind = 0 MW, DNE = 0 MW
    • Non-wind DDP = 100 MW
    • LMP = $35
  • With 50% wind
    • Exp wind = 50 MW, DNE = 50 MW
    • Non-wind DDP = 50 MW
    • LMP = $20/MWH
  • With 75% wind
    • Exp wind = 75 MW, DNE = 75 MW
    • Non-wind DDP = 25 MW
    • LMP = $20/MWH
  • With optimal wind:
    • Exp wind = 100 MW, DNE = 100 MW
    • Non-wind DDP = 0 MW
    • LMP = $20/MWH

Note – to provide clarity in the illustration of DNE dispatch principles, examples ignore some of the more complex pricing constraints in the LMP calculator

dne dispatch conceptual examples2
DNE Dispatch – Conceptual Examples

Assume a 100 MW radial line with:

  • Two 60 MW wind plants offered at $0/MWH
  • 100 MW non-wind resource offered at $20/MWH
  • $35/MWH LMP where the line connects to the meshed grid
  • With no wind:
    • Exp wind = 0 MW, DNE = 0 MW
    • Non-wind DDP = 100 MW
    • LMP = $35
  • With 50% wind
    • Exp wind = 60 MW, DNE = 60 MW
    • Non-wind DDP = 40 MW
    • LMP = $20/MWH
  • With 85% wind
    • Exp wind = 102 MW, DNE = 100 MW
    • Non-wind DDP = 0 MW
    • LMP = $0/MWH
  • With optimal wind:
    • Exp wind = 120 MW, DNE = 100 MW
    • Non-wind DDP = 0 MW
    • LMP = $0/MWH

Note – to provide clarity in the illustration of DNE dispatch principles, examples ignore some of the more complex pricing constraints in the LMP calculator

dne dispatch operational considerations
DNE Dispatch – Operational Considerations
  • Transmission lines in remote locations where many wind plants are locating tend to be “skinny”, and line limits cannot be exceeded, even for short periods
    • Normal rating = Short Term Emergency Rating = Long Term Emergency Rating
  • Another Example (using assumptions from prior slide, with several additional assumptons):
    • Expected wind = actual wind = DNE limit = 0 MW
    • Non-wind resources are operating at the limit of the line = 100 MW
    • Non-wind plant ramps at 1 MW/min
    • Wind plants each ramp at 20 MW/min, or 40 MW/min total
dne dispatch operational considerations1
DNE Dispatch – Operational Considerations
  • Along comes a proverbial “optimal wind” gust
    • Expected wind now = 120 MW
    • DNE cannot be increased until the non-wind plant has ramped down to “make room” on the line
    • Alternatively, the line can be derated to allow some room to begin wind up-ramps
    • The ISO is evaluating how best to incorporate these considerations in the DNE algorithm to ensure reliable operation at the lowest cost.
anticipated schedule
Anticipated Schedule
  • May MC meeting – conceptual overview
    • MR1 language available, but not discussed
  • June MC meeting – MR1 language presented
  • July MC meeting – request MC vote
  • August PC meeting (or later) - request PC approval
appendix
Appendix

Wind RT Dispatch Presentation to the June 12, 2012 Markets Committee Meeting

the problem1
The Problem
  • The system faces more frequent localized congestion as wind penetration increases
  • Today, this congestion must be handled manually through curtailment instructions
    • To ensure reliability, system operators must take a conservative approach. Can’t risk operating “too close to the edge”.
  • Manual curtailments do not result in price separation
    • Wind resources and other Intermittent resources are “non-dispatchable”
    • Unit Dispatch Software (UDS) is unable to manage congestion by sending dispatch instructions
    • Creates local economic incentives to maximize output when reliability requires reduced output
    • LMPs are inconsistent with “dispatch” decisions to curtail zero-price resources
other factors
Other Factors
  • When economic dispatch is insufficient to manage congestion, priority goes to resources that cleared or self-scheduled in Day-Ahead.
  • As a practical matter, this leads to economically inefficient outcomes
    • Renewable energy credits and production tax credits result in wind plants having a negative energy price
    • Interconnections on weaker portions of the grid, and fast ramp rates mean wind plants are typically curtailed more frequently than other resource types
  • Anticipated wind production generally not reflected in unit commitment for real-time
  • The ISO currently has no feasible way to dispatch wind plants that wish to offer economically
why now
Why Now?
  • New England wind penetration has been doubling every year
  • Currently at 525 MW
  • Likely 900 MW by end of 2012
  • If Congress renews provisions for Production Tax Credits, wind resources could reach 1500-1700 MW by end of 2013
    • Existing manual curtailment procedures cannot effectively manage this amount of wind generation
  • Software infrastructure to support Wind RT Dispatch can be ready in 2014
    • Sooner would be better, but Wind Dispatch depends on other dispatch software improvements already underway
what s wrong with the status quo
What’s Wrong with the Status Quo?
  • Lack of real-time telemetry and uncertainty about anticipated wind output lead to:
    • More conservative operating practices and limits
    • Less optimal resource commitment
  • Suboptimal dispatch and inappropriate pricing
    • Low cost resources may be curtailed before higher cost resources
    • Manual curtailments to manage congestion don’t result in price separation
  • With higher wind penetration, system operators with only manual dispatch & curtailment procedures will be overloaded during dynamic weather conditions
enabling improvements are already underway
Enabling Improvements Are Already Underway
  • Wind short-term forecast – early 2013
    • Highly accurate 5-minute forecast for each wind plant
    • Hourly forecasts for the coming 7 days
  • OP-14 & OP-18 – real-time telemetry from wind plants
  • Both of these:
    • Greatly improve operator situational awareness
    • Reduce uncertainty
    • Improve commitment and dispatch of all resources
    • Make possible a real-time “Do Not Exceed” (DNE) dispatch of wind resources
what is a do not exceed dispatch
What is a “Do Not Exceed” Dispatch?
  • UDS will calculate and send out a Do Not Exceed limit to each wind plant on dispatch
  • The DNE limits will reflect
    • Each plant’s economic offer curve
    • The maximum output of each wind plant under ideal weather conditions
    • Transmission constraints
    • Each plant’s telemetered physical status for the next dispatch interval
    • Current plant output (the so-called “persistence forecast”)
    • high-confidence “next 5 minutes” wind output forecasts
  • A wind plant is free to operating anywhere between 0 MW and the DNE limit
  • Considers both energy balance (i.e. gen = load) and reliability
how will wind rt dne dispatch work
How Will Wind RT DNE Dispatch Work?
  • The DNE limit reflects the maximum plant output that can be tolerated, given system conditions and constraints
  • Wind plants will be considered “following dispatch” if operating between 0 MW and the DNE limit and not exceeding ramping limits.
    • Output can vary with changing weather conditions
    • Downward ramps due to plant emergencies and/or decreasing wind not counted for “following dispatch”
  • Wind plants on dispatch will be eligible to set price
  • DNE dispatch allows UDS to perform price-based congestion management based on offer parameters
    • Will prevent “manual procedure” overload for system operators
  • Accurate forecasts and frequent telemetry should reduce curtailments and provide greater opportunity to maximize output.
dne dispatch will initially be optional
DNE Dispatch Will Initially Be Optional
  • DNE dispatch implementation currently estimated for 2014
    • Wind resources will be non-dispatchable until DNE dispatch is available
    • Once available, DNE dispatch may be optionally selected by wind plants through their offer data
  • If/when negative energy offers become available, MR1 would be revised to make DNE dispatch mandatory for wind plants that meet one or more of the following conditions:
    • Interconnect to a transmission facility or a FERC jurisdictional distribution facility
    • Has a Capacity Supply Obligation
    • Is a Capacity Network Resource
    • Has a total nameplate capacity at the point of interconnection of >= 5 MW
    • Possible exclusion for “Settlement Only Generators” – may depend on operational needs of System Operators
other participation considerations
Other Participation Considerations
  • Must be providing all weather and plant data required by recent OP-14 & OP-18 changes
    • This data supports the forthcoming real-time wind forecast system
    • Accurate real-time wind production forecasts are critical to effective operation of the DNE dispatch
  • No requirement to offer into Day-Ahead
  • Self-scheduling will continue to be permissible while Wind RT Dispatch is voluntary.
  • Assuming a dispatchable wind plant offers $0 commitment costs, it will be treated as “committed” whenever available (i.e. RTHOL > 0)
    • Otherwise, must offer & clear in DA, or self-schedule in RT
concluding remarks
Concluding Remarks
  • Voluntary Wind RT DNE Dispatch – mid-2014
    • Market rules being presented today only address voluntary DNE dispatch
  • Partial/voluntary implementation:
    • Provides early operational/reliability benefits
    • Does not fully resolve pricing and congestion management issues
    • That requires that all wind plants are responding to DNE dispatch instructions
  • Full reliability benefit occurs only when Wind RT Dispatch becomes mandatory
    • Not anticipated until negative offers can be implemented (likely not until 2014 or 2015)
    • Mandatory Wind RT Dispatch will require a separate rule change
anticipated schedule1
Anticipated Schedule
  • May MC meeting – conceptual overview
    • MR1 language available, but not discussed
  • June MC meeting – MR1 language presented
  • July MC meeting – request MC vote
  • August PC meeting (or later) - request PC approval
appendix1
Appendix

Current Curtailment Protocol

existing rt dispatch and congestion management
Existing RT Dispatch and Congestion Management
  • Existing real-time curtailment procedure
    • Economic dispatch – most-expensive dispatchable resources (based on sensitivity to the constraint) backed down first
      • Self-scheduled/non-dispatchable resources not impacted at this point
    • Resources that did not offer and clear in Day-Ahead
      • Resource with largest impact on the constraint curtailed first, as long as it can respond quickly enough
      • If not, other resources may also be requested to reduce output
    • DA-cleared/self-scheduled resources backed down last
  • Self-scheduling in DA
    • If multiple SS requests result in constraint violations, ISO rejects the request(s) that results in the least cost solution
existing rt dispatch and congestion management1
Existing RT Dispatch and Congestion Management
  • Self-scheduling in RT
    • A SS request (effectively priced at $0/MWH) is accepted if it can be accommodated by backing down DA-cleared resources to their EcoMin/SS amount
    • If congestion develops and all online resources are RT SS at EcoMin, operators will manually deny self-schedules as needed
      • Solves the reliability problem, but does not result in price separation
  • If further action is required, operators may de-commit resources, taking into consideration:
    • Sensitivity to constraint, system/area capacity, EcoMax/EcoMin, Min Run & Min Down times, economics
  • Interconnections on weaker portions of the grid, and fast ramp rates mean wind plants are typically curtailed more frequently than other resource types.
ad