Day-ahead market enhancements discussion Ryan Kurlinski Manager - - PowerPoint PPT Presentation

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Day-ahead market enhancements discussion Ryan Kurlinski Manager Department of Market Monitoring, CAISO Market Surveillance Committee Meeting General Session July 30, 2020 ISO PUBLIC ISO PUBLIC CAISO real-time flexible ramping product

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Day-ahead market enhancements discussion

Ryan Kurlinski Manager Department of Market Monitoring, CAISO Market Surveillance Committee Meeting General Session July 30, 2020

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CAISO real-time flexible ramping product overview

Commits and dispatches resources to position fleet to meet

uncertainty over what net load will be “15 minutes” from current interval

– Flexible capacity paid marginal cost to objective function of making capacity available

Design enhancements are needed:
Locational procurement

– Aimed at reducing “stranded flex ramp” in areas that cannot be used due to transmission limits. – CAISO addressing in current stakeholder initiative.

Incorporate uncertainty about what net load will be 1 to 4 hours
ut from current real-time market run

– This presentation explains this recommendation and implications for imbalance reserves product

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To increase upward ramping capacity, CAISO grid operators make significant upward adjustments to the demand for energy used by the real-time market software to dispatch bids.

4,000 8,000 12,000 16,000 20,000 24,000 28,000 32,000 36,000 200 400 600 800 1,000 1,200 1,400 1,600 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Net system load (MW) Manual load adjustment (MW) Hour of day ( July - September 2019) Hour-ahead load adjustment 15-minute market load adjustment 5-minute market load adjustment Net load

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CAISO operators also commit extra gas-fired capacity after day-ahead market and ramp units up in real-time to create more upward ramping capacity.

These are referred to as out-of-market or exceptional dispatches.

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5,000 10,000 15,000 20,000 25,000 30,000 35,000 100 200 300 400 500 600 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Average system net load (MW) Average hourly energy (MW) Hour of day (July - Sept 2019)

Other real-time manual energy dispatches (gas units only) Manual energy dispatches to increase ramp/manage load uncertainty Minimum operating level of gas units comitted manually Net load

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In real-time, the market software uses net load forecast for every interval up to 4.5 hours in future to determine optimal schedules at the current interval (e.g. 13:45 in this example).

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Picturing uncertainty: probability density functions

At a given point in time, net load at a time in the future is a random variable with a range
f uncertainty that can be characterized by a probability density function.
A wider probability density function indicates wider range of uncertainty.
CAISO characterizes upper end of range of possible outcomes using 97.5th percentile.

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At 13:45 the uncertainty over what net load may actually be at each point in time over the next 4.5 hours grows further out in the future.

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Flexible ramping product has improved real-time software by considering some uncertainty around the net load forecast for every interval 4.5 hours in future used to determine optimal schedules at the current interval.

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The “15 minute” uncertainty used by FRP is substantially less than actual uncertainty over what net load forecast may be 1 to 4 hours in future

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The real-time market software does not optimally position resource fleet to meet potential high net load outcomes 1 to 4 hours in the future.

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For example, software will miss opportunity to start units with 3 hour start times that are needed by 17:00 to meet potential high net load outcomes– requires manual operator interventions

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Considering actual net load uncertainty 1 to 4 hours in future would allow the real-time software to position resources to meet higher potential net load outcomes.

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Procuring flexible capacity in day-ahead market does not solve problem

CAISO is currently designing “imbalance reserves” product—

ramping capacity in day-ahead market to address uncertainty in net load between day-ahead and real-time.

Real-time market re-optimizes DAM schedules and most DAM

commitments

If real-time flexible ramping product is not enhanced to consider

uncertainty 1 to 4 hours out, manual operator interventions still required in real-time.

Regional day-ahead market: Real-time manual operator

inventions in one BAA will be required to preserve imbalance reserves for another BAA.

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