Threats to the Power System
Energy Risk and Critical Infrastructure WorkshopNational Conference of State Legislatures
William P. Mahoney IIIDeputy Director, Research Applications Laboratory
National Center for Atmospheric Research, Boulder, Colorado, USA
NCAR is a Federally Funded Research & Development Center (FFRDC)
Administered by consortium of 105 Ph.D.-granting North American universities through the University Corporation for Atmospheric Research (UCAR), a not-for-profit 501(c)(3) organization.
UCAR International Affiliates: A group of 33 international institutions with strong connections to UCAR/NCAR
National Center for Atmospheric Research
Wind and Solar Resource Assessment
Wind and Solar Energy Prediction
Load Prediction
Met-ocean Conditions Prediction
Hurricane Characterization & Prediction
Climate Change Impacts
Energy Related Research
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Mother Nature Is Not Always Kind!
Tornado damage
NWS
Turbine blade icing
Over speed damagePowerline icing
Wildland fire
Utility products
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Mother Nature Is Not Always Kind!
Wind DamageMicrobursts
KCTV News Kansas CityJune 2015
NWSJune 2006, Ohio
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Hurricane Sandy Utility Damage (NY)
Credit: George Tech
Impact
600,000 customers in 4major service areas
28 million customer interruption hours
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Weather Impacts to Utilities
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Weather Impacts to Utilities
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Weather threats to the power system
• High wind• Lightning• Ice and heavy snow• Wildland fire• Clouds (solar energy)• Turbulence & wind shear• Excessive heat (transmission)• Thunderstorm gust fronts• Hurricanes• Drought• Space weather
Ozarks ElectricalCooperative
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Wind Generator Scale
Source: Terra Magnetica
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Overarching Wind Energy Science Challenges
• Boundary layer meteorology (0 to 200 m above ground) is not well understood nor is this layer well measured
• The wind energy industry greatly under appreciates the complexity of the airflow in this layer
• The wind industry has historically assumed less turbulence and more wind with height above the ground
Image source: Wind Measure International
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Overarching Solar Energy Science Challenges
Improve prediction needed of:• Cloud lifecycle• Aerosols• Jet Contrails• Surface conditions (snow/ice melt on solar devices)
• Cloud and precipitation processes are highly complex and operate on very small scales (10s to 100s of meters)
• Weather models greatly over simplify cloud physics properties and precipitation processes.
• Jet contrails can spread into a cirrus deck and are not predicted by any models
Low-Level Jets of High Wind (U.S. Midwest)
Courtesy, Robert Banta, NOAA
Height(km)
Lidar (laser radar) measured wind velocitytoward lidar
Low-level jet streams can damage wind generators
Distance (km)
10 ms-1 ribbon of high speed air
Wind Variability at Turbine Height Can be Substantial
Courtesy Ned Patton, NCAR
Wake Effects of Turbine Arrays
Courtesy Branko Kosovic, NCAR
Turbine wakes result in power loss, turbulence, wind shear and overall wear and tear on the turbines drive trains
Wind Shear vs. Turbine Efficiency
Low-level Jet Wind RampCold Front Wind Ramp
Knowledge of the wind profile is important for wind to power conversion – Shear across blades can reduce efficiency by up to 20%!
(Lundquist and Wharton, 2009)
(T. Aguilar, 2010)
Wind Energy Ramps – Colliding Gust Fronts
Colliding thunderstormgust fronts in Texas
Mahoney 1988
Wind Energy Ramp Events
8/03/09 771mw up-ramp from 20:10 - 22:10 followed by a 738mw down-ramp from 22:40 - 00:50
-100
0
100
200
300
400
500
600
700
800
900
16 :5017 :10
17 :3017 :50
18 :1018 :30
18 :5019 :10
19 :3019 :50
20 :1020 :30
20 :5021 :10
21 :3021 :50
22 :1022 :30
22 :5023 :10
23 :3023 :50
0:100:30
0:501:10
1:301:50
Ponnequin
Ridgecrest
Spring Canyon
Cedar Creek
Logan/Peetz Table
Colorado Green/Twin Buttes
MW
TIME
800 MW in < 2 hrs.
small thunderstorms
cold front
Complex Flows – Offshore Wind
For offshore applications it is important to capture wind and wave interactions
Peter Sullivan, NCAR
Waves generate their own wind field that persists to hub height
Moving waves
Hurricane Flow Characterization Complexities
(Rich Rotunno, NCAR
WRF Hurricane SimulationLarge-Eddy Simulation (LES)190 ft (62 m) resolution
Resolving turbulence scales
How do wind turbines respond to hurricanes, typhoons and USA Nor’easters?
Future Climate Impacts
Climate Scenarios of Wind and Solar Resources 2040-2070• Developed for National Renewable Energy Laboratory (NREL)
• Data for Regional Energy Deployment System (ReEDS)
• Datasets – CFDDA, NARCCAP, CCSM
Offshore Oil Operations
Offshore oil operations are heavily sensitive to the met/ocean environment.
Source: APSource: Rick Adams
Lack of Water - Drought
Power plants that have shut down or reduced output due to water problems
2006-2013
Source: Davis & Clemmer, 2014
Technology Highlights
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Wind Energy Prediction System• Developed for Xcel Energy Services, Inc.
• Includes ~6GW
• Saved Xcel ratepayers $49M since 2010
Xcel Energy annual revenue $11B
Technology Highlights
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Solar Energy Prediction System• Department of Energy sponsored project
Generates spatially continuous estimates of hydrologic states (snowpack, soil moisture, evapotranspiration, inundation)
Uses modeling architecture that permits rapid infusion of new data and science
Current NWS River Forecast Points (~3,600)
NWM River Forecast Points (~2.7 million)
Modeling and Data Assimilation Review | 6-8 June 2016Modeling and Data Assimilation Review | 6-8 June 2016
Hydro-meteorology
NCAR Hydro Model New National Water Model
Modeling and Data Assimilation Review | 6-8 June 2016Modeling and Data Assimilation Review | 6-8 June 2016
WRF-Hydro National Water Model
Thank You
Source: AfricaBriefing.org
