Power Association of Northern California

Maintaining Grid Reliability In An Uncertain EraMay 16, 2011PG&E Conference Center

Jim Mcintosh

Director, Executive Operations Advisor

California ISO

Slide 2

The Challenges & How We Plan To Address Them

• Forecasting• Generation fleet characteristics• Ramping requirements• Ambitious environmental goals• Reliability with fewer gas powered plants• Cost containment

• We need to strike a balance between reliability, renewables, and reasonable cost.

Slide 3

Policy Drivers

• State law AB32 – reduction of greenhouse gas emissions to 1990 levels by 2020– Western Climate Initiative

• 20% Renewable Portfolio Standard (RPS) by 2012-2013

• 33% RES by 2020 (Executive Order)

• Repowering or replacement of once-through cooling power plants (~34% of in-state gas and nuclear capacity)

Slide 4

Additional Supply Side Policies

• Small-scale renewable feed-in tariff program– Resources must be smaller than 1.5 MW and the cap is 480-500 MW

• Storage bill AB2514 (Sept. 2010)– Requires the CPUC to consider and adopt procurement targets for

viable and coast-effective energy storage systems.

Slide 5

Location of OTC plants in local capacity requirement (LCR) areas within CAISO

*Retired out 2010

-

1,000

2,000

3,000

4,000

5,000

6,000

7,000

Biomass/Biogas Solar Geothermal Small Hydro Wind2006 701 420 1,101 614 2,648

2012 (expected) 701 2,246 2,341 614 6,688

Slide 6

MW

The 2-3 year look-ahead: renewable resource portfolios in 2006 and 2012 (20% RPS), by capacity (MW)

Slide 7

The ISO grid control room faces significant short- and long-term challenges

• Uncertainty of grid infrastructure development

• Ramping requirements significantly increased

• Continued development of control room tools

• Load and wind forecasting accuracy

• Rapid changes in grid generation fleet, especially wind and solar technologies

1. Wind and solar variability will be a significant issue by 2012-2013.

2. Synchrophasors are the most significant advancement in control center technology in the last 30 years.

Slide 8

These challenges can be addressed through improved control room tools (Synchrophasors) and training

• Wind and solar modeling & production forecasting

• State estimator solution & accuracy

• Grid reliability & engineering studies

• Network and market modeling

• Awareness of regional disturbances (e.g. 1996 event)

• Dynamically assess the grid (EMS not sufficient)

• 30 samples per second compared to once every four seconds

• Can increase COI transfer by 1500 MW

• Estimated reduction in congestions costs $250 million

• Better real time visualization

Challenges of Fossil Fuel and Wind Generation

Slide 9

Predictability

No surprises

Dependable energy schedules

Accurate forecasts

Contingency reserves available

Generators that follow dispatch commands

Excellent tools for visibility of system status

High quality data

De-rate information on units is timely and accurate

GRID OPERATORS

Hard to predict

Shows up unscheduled

Maximum generation at night when loads are low and there is no place for the energy

Large ramp changes both up and down

Lack of good data from wind generation facilities

Lack of visibility on what wind generations are doing

Don’t follow dispatch commands ---treated as “Must Take” generation

WIND GENERATORS

Slide 10

Difficulty of Predicting Wind Energy

Average

Total Wind Generation

0

200

400

600

800

1000

1200

1400

1600

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

MW

Wind activity across a 24 hour period.

Slide 11

RAMPING!

Wind generation tends to be inversely correlated to daily load curve, creating ramping impacts

CAISO Load vs. Total WindSummer 2006

22,000

24,000

26,000

28,000

30,000

32,000

34,000

36,000

38,000

40,000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hours

Lo

ad

MW

0

100

200

300

400

500

600

700

800

900

1,000

1,100

1,200

Win

d/S

ola

rM

W

Load Total Wind Solar

Slide 12

Photovoltaic Plant Output on a Partly-Cloudy Day

10 Second Sample – March 25, 2008

13

Requirements for Integration of Renewables

GenerationPortfolio Storage

DemandResponse

Resources Required for Renewables Integration

Quick Start Units

Fast Ramping

Wider Operating

Range (lower Pmin)

Regulation capability

Shift Energy from off-peak to on-peak

Mitigate Over Generation

Voltage Support

Regulation capability

Price sensitive load

Responsive to ISO dispatches

Frequency Responsive

Responsive to Wind Generation Production

“Partners in Success”

Wind Generation

Solar Generation

Hydro Generation

Geo-thermal

Generation

Slide 14

New record Wind production

About 40 mws

Each cell is 2 hours

Day ahead schedule

Green is actual production