New Electric Grid Technologies for Renewable Generation Deployment Presented to ICEPAG 2011 February 8-10, 2011 Costa Mesa, California By Merwin Brown, PhD Program Director, Electric Grid Research University of California February 9, 2011 This presentation is based in part on work sponsored by the California Energy Commission, but does not necessarily represent the views of, nor has it been approved or disapproved by, the Energy Commission.
For most of the 20 th Century, transmission had a relatively simple role moving electricity from central power plants to the consumers. Transmission system behavior was predictable, and under the close control of an operator - much like conducting an orchestra. 2
But conducting the 21 st century electric grid is becoming a more hair raising experience: Being connected to the world s largest machines, i.e., a multi-state, multi-country, brittle power grid Accommodating competitive wholesale power markets Serving growing and changing electric loads that are becoming part of the orchestra Dealing with economic and public policy pressures Being instrumental for meeting aggressive renewable energy goals 3
Renewable resources portfolio mix for 33% by 2020 might look like this Wind Biomass Solar Geothermal And variable wind and solar resources will be a large part of the mix. 4
But to grid operators, 33% renewables looks more like this The Saga of Renewable Generation and Grid Integration reveals many challenges. 5
The Saga of Renewable Generation and Grid Integration Most central station generation will be located remote from customers. HIGH WINDS............... Provide Access Building new transmission lines is becoming increasingly difficult and taking longer. 6
Building new transmission lines is becoming increasingly difficult and taking longer. Proving need and value Distributing benefits & allocating costs $X New NIMBY Line Assessing and mitigating environmental, land use & aesthetic impacts Getting approval from multiple agencies and jurisdictions Delay in siting & building new transmission is often cited as major barrier to meeting renewable generation policy goals. 7
Some renewable generation is unique, e.g., Intermittent Fast Ramp-Rates Over Supply Low Inertia The Continuing Saga of Renewable Generation and Grid Integration Renewable Power Plant............... The power grid system must accommodate generation s unique behaviors. 8
Wind generation can vary widely from day to day and hour to hour. Thanks to Tehachapi-area, April 2005 Wind generation is a challenge to forecast. 9
Typical load & wind profiles are almost inverse images. CAISO Load -- Summer 2006 40,000 38,000 36,000 34,000 Load MW 32,000 30,000 28,000 26,000 24,000 22,000 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 Total Wind -- Summer 2006 MW 1,200 1,100 1,000 Wind Generation 900 800 700 600 500 400 300 200 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 Creates issues with oversupply and loadfollowing ramping. Thanks to 10
Solar generation can vary widely from day to day and hour to hour. PV output on sunny day in NV (10 sec sampling) PV output on partly cloudy day in NV (10 sec sampling) Source: NERC Report - Accommodating High Levels of Variable Generation March 2009 11
Projected Profiles of Wind +Solar Thanks to Wind and solar generation combined appear to make ramping worse. 12
Variable generation can increase the need for system flexibility. Thousands of MW of new rapidly dispatchable generation required for ramping. Source: NERC Report - Accommodating High Levels of Variable Generation March 2009 13
Existing infrastructure is constrained. The Continuing Saga of Renewable Generation and Grid Integration............... Increase Capacity Renewable Power Plant Difficulties with siting new or upgrading existing transmission Thermal Limits Stability Constraints (Voltage, Transient, Dynamic) N-1 Contingencies 14
There are essentially two options for successful expansion and operations of T&D: The traditional build solutions, i.e., investments in wires, towers, poles and power plants, and Renewable Power Plant............... Improved or new T&D functionalities to make expansion and operations easier and less costly. 15
For now we can build our way out of these problems, but at higher renewable penetrations traditional build solutions, i.e., investments in wires, towers and power plants, can t do it alone. New technologies will be needed to make renewable integration easier and less costly especially technologies that make the grid smarter 16
New Technologies to Provide Faster Access for New Renewable Plants by putting new power lines in a better light. Underground Transmission High Voltage Direct Current Engineered Compact Designs Advanced Transmission Line Conductors Distributed Renewables & Demand Response Web-based Interactive Stakeholder Siting Tools Cost Allocation & Strategic Benefit Analysis Tools 17
New Technologies to Accommodate Unique Renewable Generator Behaviors through a smarter and more flexible grid. Tehachapi Wind Generation - April 2005 Intermittency Ramp Rate Inertia Over Supply Energy Storage & Intelligent Agent (temporal power flow control) Solar and Wind Forecasting Tools Generator and Load Modeling Demand Response Synchrophasor Monitoring Power Flow Control (spatial) Distributed Generation Advanced Intelligent Protection Systems Statistical and Probabilistic Forecasting Tools 18
New Technologies for Increased Grid Power Capacity by optimizing the grid for greater power flow. North-South COI California Desert Southwest Dynamic Thermal Ratings Real-Time System Ops (synchrophasors) Power Flow Control (spatial) Energy Storage (temporal power flow control) High Voltage Direct Current Distributed Generation & Demand Response Advanced Intelligent Protection Systems Statistical & Probabilistic Analysis & Planning Tools Advanced Transmission Line Conductors 19
Example: Increase Capacity: Two Views: California-Oregon Intertie August 10th, 1996, Power Flow During Generator Trip Observed COI Power (Dittmer Control Center) What synchrophasors showed Simulated COI Power (initial WSCC base case) What the operators saw This event triggered an inter-area power oscillation and ended in a wide-area power outage in western US. 20
A number of these oscillations are showing up annually, and are a cause of growing concern. Alberta 0.45 Hz North South 0.25-0.3 Hz East-West 0.6-0.7 Hz California Desert Southwest 0.5 Hz Oscillations have caused western transmission capacity to be derated by thousands of MW, restricting the export/import of renewable power. System inertia is thought to be a factor. 21
Some renewable generators have low or no inertia. Traditional (thermal) power plants have inertia in the rotational mass of their turbine-generators. Some renewables exhibit traditional inertia Wind and some solar exhibit low or no inertia. If large amounts of renewables worsen the oscillation threat, how will the grid operator be able to respond? 22
Synchrophasor Measurements The Basis of the Smart Grid Transmission jfh 01/24/95 PRINCE RUPERT PEACE CANYON PSM DSM WILLISTON PPSM * SUNDANCE KEMANO MICA PPSM LANGDON VANCOUVER AREA DSM SEATTLE PPSM AREA PPSM DSM DSM GPS Satellite DSM PPSM PORTLAND AREA PSAM PPSM PPSM CHIEF JOSEPH PPSM GRAND COULEE PPSM HELLS CANYON HOT SPRINGS FT. PECK PPSM COLSTRIP PPSM * SAN FRANCISCO AREA SHASTA DSM MOSS LANDING LOS ANGELES AREA BOISE BURNS WECC MIDPOINT MALIN ROUND MTN TABLE MTN SALT LAKE * PSM CITY AREA * DELTA * DSM DSM PPSM DSM LUGO PSM DSM PHOENIX PPSM AREA * MOJAVE DEVERS HOOVER DSM PALO VERDE PPSM * PPSM PINTO NAVAJO PSM * PPSM * CORONADO DSM FOUR CORNERS PPSM * PPSM MONTROSE * ALBUQUERQUE AREA EL PASO AREA DENVER AREA MIDWAY jfh Time-Stamp John Day Malin Summer L Slatt McNary Useful Real-Time Information PPSM DSM HVDC Terminal Phase-Angle Measurement Unit (Macrodyne) Portable Power System Monitor (BPA) Dynamic System Monitor (PTI/Hathaway) PSAM PSM MEXICO Power System Analysis Monitor (BPA) Power System Monitor *Proposed installation Projected WSCC Monitors, 1995 s (Phasor Measurement Units) Voltage - kv 575 550 525 500 475 450 Data 425 Grizzly reactor #2 Grizzly reactor #3 Time Synchronous Data Ashe reactor 30 60 90 120 150 180 210 240 Time - seconds Control Center Courtesy of EPRI Are like X-ray to MRI improvements in diagnostics capability. 23
The Before and After of Synchrophasor Measurements Synchrophasors 30/second ^ ^ Traditional Real-Time Data Rate = Every 4-5 seconds Disturbances System Planning System Operation Automatic Control Power System Unobserved Response Observed Response WECC Decision Processes Information Measurement Based Information System An unprecedented ability to see, know, plan and control. 24
CAISO, SCE, PG&E, and SDG&E Are Pioneering the Use of Phasor Technologies in California Compliments of CERTS
Mode Estimate: Example Poorly Damped Mode Alarm Threshold <3% damping Oscillatory Frequency (Hz) Alert Threshold <5% damping Damping Ratio (%) Photo courtesy CERTS 26
At the other end of the grid, DG renewables offer their challenges Safety Reverse power flow Voltage highs and lows VARs Power quality Equipment accelerated fatigue and thermal damage Smart grid is part of the answer. Photo courtesy CERTS 27
Smart Grid formed by joining 2 infrastructures Electrical Infrastructure Synchrophasor Measurement s The digital smart Intelligence meter makes the customer an integral part of Infrastructure the electric grid. 28
Past... The Smart Meter Future... Utility Bill Sensors
For additional information or discussion, contact : Merwin Brown Director, Electric Grid Research Voice: 916-551-1871 Merwin.Brown@uc-ciee.org www.uc-ciee.org And he ll find someone to help you. People tend to overestimate what can be accomplished in the short run but to underestimate what can be accomplished in the long run. Arthur C. Clarke 30