Flexibility and Storage for Integration of Renewables

Transcription

1 1 Flexibility and Storage for Integration of Renewables Senior Analyst, Renewable Integration and Integrated Resource Planning Pacific Gas & Electric January 25, 2011

2 2 Outline I. Background II. Renewable Integration in California III. PG&E s Storage Projects IV. On-going Industry Initiatives

3 3 Background

4 4 California Future Generation Mix Source: CPUC, 33% RPS Implementation Analysis Preliminary Results. June, 2009, California Public Utilities Commission

5 Wind and Solar are Highly Variable Wind and solar are variable resources: Variability: the magnitude of power output from one moment to the next can change dramatically Unpredictability: sudden changes in generation output not wellforecasted 5 CAISO July 2009 Wind Generation, MW Solar Generation in Springfield, AZ Sources: Apt J. and Curtright A., Spectrum of Power from Utility-Scale Wind Farms and Solar Photovoltaic Arrays

6 MW MW Flexibility and Storage for Integration of Renewables Flexible Resources Maintain Balance Flexible generation manages uncertain real-time load and generation 6 55,000 55,000 50,000 50,000 45,000 45,000 40,000 40,000 35,000 35,000 30,000 30,000 25,000 25,000 20,000 20,000 15,000 15,000 10,000 10,000 5,000 5,000 Load Load Real-Time Load Uncertainty and Forecast Generation (CA 5 Minute Load 11am-12pm Peak Day 2005 and Hypothetical Generation) Hours 41,500 41,300 5 Min Avg Load with Intra 5 Min Vol bounds 41,100 40,900 40,700 40,500 40,300 40,100 39,900 39,700 39, Min Avg Load

7 Flexible Resource Provide Ancillary Services Load Following: Difference between the hourly schedule (red line) and the 5-minute schedule (blue line) Regulation: Difference between the 5-minute schedule (blue line) and the actual load/wind (green line) 7 Source: California ISO

8 8 Renewable Integration in California

9 Integration Framework to Determine Flexibility Need 9 Reserve Requirements Additional System Requirements Technology Mix and Costs Define reserve requirements based on load and generation characteristics Evaluate system operation to determine additional resource needs and characteristics (MW, ramp times, etc) Determine mix of technologies for meeting system needs weighed against costs

10 10 Integration Studies in California There is no standard approach to estimate flexibility needs Approaches Explanation Advantages CAISO Study Production simulation model using Plexos Simulate operation of grid hourly Identify and solve operating violation by adding flexible capacity Detailed representation of grid Existing and new resource limitations represented Renewable Integration Model (PG&E) Estimate flexibility need analytically Simplified representation of key drivers of flexibility need Produces results in minutes Can vary/test sensitivity of results Accessible (uses simple tools) Disadvantages Requires thousands of assumptions Slow (takes days) to estimate need Becomes outdated fast Simplified representation of grid Need to calibrate results

11 MW Flexibility and Storage for Integration of Renewables 11 Integration Needs Defined 9,000 8,000 7,000 Statewide Maximum Operating Flexibility Requirements (Summer Season) 6,000 5,000 4,000 3,000 2,000 1, PG&E RIM 20% RPS in 2020 PG&E RIM 33% RPS in 2020 CAISO 33% RPS IN 2020 Regulation Load Following Day-ahead Commitment

12 12 Sources for Flexibility Source: P. Denholm, NREL, 2010; B. Nickell, DOE, 2008

13 13 PG&E s Storage Projects

14 14 Helms Pumped Storage Plant Location Central California Commissioned June 30, 1984 Installed Capacity Three units; 1,212 MW generating; 930 MW pumping Storage of economy energy at night and spring run-off Alleviate over generation and minimum load conditions Meet fluctuations in demand and act as reserves

15 15 Current Storage Initiatives CAES NaS Battery Pumped Hydro Existing salt dome reservoir Partnership with DOE, CEC, CPUC 300MW, up to 10* hours storage 4 MW system in San Jose 2 MW system at Vaca-Dixon substation Test load shaping, providing ancillary services, balancing solar Mokelumne Proposal to connect 2 reservoirs * Final project size to be determined

16 16 Current Industry Initiatives

17 17 CAISO: REM Initiative Regulation Energy Management (REM) Program to test usefulness of limited energy resources (batteries) for regulation services Source: CAISO, Regulation Energy Management Draft Final Proposal Dec 14, 2010

18 18 CPUC AB2514 Directs California Public Utilities Commission to: Determine targets, if any, to procure viable and costeffective energy storage Adopt by October 1, 2013, an energy storage system procurement target, if appropriate. Approved by Governor September 29, 2010 CPUC initiated Order Instituting Rulemaking (OIR) on December 21, 2010

19 19 Conclusion At penetrations of 33% of electricity from renewable resources, changes will be required in the supply portfolio. At higher penetrations, highly flexible resources will be essential. A mix of supply-side and demand-side resources (including storage) will create a flexible electric supply portfolio. On-going industry initiatives to investigate storage in California

20 20 Thank You