Briefing on Exceptional Dispatch Gregory Van Pelt Interim Director, - - PowerPoint PPT Presentation

Briefing on Exceptional Dispatch

Gregory Van Pelt Interim Director, Grid Operations Board of Governors Meeting General Session September 10 - 11, 2009

What is “exceptional dispatch” and why is the ISO relying on it?

What?

! Committing resources and instructing output changes

• utside of market mechanisms

! Being used more than expected

Why?

! Meeting reliability requirements

! Voltage ! Contingencies

! Overcoming model and software limitations

Slide 2

The ISO committed to reducing reliance on exceptional dispatches.

! Gained market experience not available in simulation ! Formed Exceptional Dispatch Strike Team

! Analyze process and tools ! Evaluate potential software changes ! Determine process changes ! Assess changes to tariff or business practice manuals ! Emphasize continuous improvement in data quality

Results:

! Refined process to reduce exceptional dispatch ! Increased reliance on market

Slide 3

We’ve made progress in reducing reliance on exceptional dispatch in the day ahead.

Post-DAM Unit Commitment

1-May 8-May 15-May 22-May 29-May 5-Jun 12-Jun 19-Jun 26-Jun 3-Jul 10-Jul 17-Jul 31-Jul 7-Aug 14-Aug 21-Aug 28-Aug 24-Jul

10 20 30 Frequency

Pre-DAM Unit Commitment

Slide 4

The overall volume of exceptional dispatch (MWh) has been significantly reduced.

Slide 5

• 10000

10000 20000 30000 40000 50000 1-May 8-May 15-May 22-May 29-May 5-Jun 12-Jun 19-Jun 26-Jun 3-Jul 10-Jul 17-Jul 24-Jul 31-Jul 7-Aug 14-Aug 21-Aug 28-Aug MWh

Min-Load MWh RT Inc MWh RT Dec MWh

c

Exceptional dispatches are a small portion of total load, and a smaller percentage as load increases.

0% 1% 2% 3% 4% 5% 6% 7% 8% 1-May 8-May 15-May 22-May 29-May 5-Jun 12-Jun 19-Jun 26-Jun 3-Jul 10-Jul 17-Jul 24-Jul 31-Jul 7-Aug 14-Aug 21-Aug 28-Aug Percent

Percent of Load Monthly Average

Slide 6

Reliance on exceptional dispatch will be substantially reduced by the following actions:

! Including more constraints ! Additional use of RUC ! More complex modeling in IFM ! True-up market to real flows ! Multi-stage generation ! Multi-day bridging ! Transmission upgrades ! Software enhancements

30 days 60-90 days BPM change process Stakeholder input Up to 1 year 1 to 2 years PTO dependent Undetermined

Slide 7

Exceptional dispatches may always be required for adverse operating conditions or intertie reductions