Bill Blevins Sep. 24, 2014 PV Forecasting RFP. 2 Projected Installed Capacity of PV in ERCOT.

Bill Blevins

Sep. 24, 2014

PV Forecasting RFP

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Projected Installed Capacity of PV in ERCOT

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PV Short-term Forecast

Value of solar forecasts to bulk power system reliability• To assist the balancing area operators in performing their duties• To enhance the economic efficiency and manage bulk power system

reliability operational affects on the remainder of the generation fleet

Key Features:• Address photovoltaics (PV) only• Centralized solar forecast

• Benefits of size• Different forecasts for different uses and time periods

• Next hours forecast• Next day forecast

• Unbiased forecast typically the 50% POE (probability of exceedance)

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Experiences with Wind Forecast at ERCOT and Potential Needs for PV Forecast

• Delivery: Hourly - 15 minutes after the hour (may change this)

• Forecast period: rolling 48 hour ahead forecast

• Forecast parameters for each WGR

- Average hourly MW

- 50% POE MW (labeled as STWPF used for COP)

- 80% POE MW (labeled as WGRPP)

Short Term Wind Power Forecast

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NPRR 615 PVGR Forecasting

PVGRPP PhotoVoltaic Generation Resource Production PotentialSTPPF Short-Term PhotoVoltaic Power ForecastPVGR PhotoVoltaic Generation Resource

Approved by Board of Directors on Aug. 12, 2014

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• Global Solar Irradiance (~90%), • Temperature (~10%), • Wind (<1%)• Type of Plant

– Determines exact impact of all three factors– Categories of plants: (1) PV, (2) Concentrating PV, (3)

Solar thermal (also concentrating)– PV is sensitive to Global Irradiance– Concentrating types (thermal and PV) are sensitive to

Direct Normal Irradiance– Also significant sensitivity variations within basic categories

Factors that Affect Solar Power

Solar Power Forecast Challenge

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Making the Best Forecast for Various Time Scales

Minutes Ahead•Cumulus clouds, small-scale cloud structures, fog•Rapid and erratic evolution; very short lifetimes•Mostly not observed by current sensor network•Tools: persistence, skycams, local irradiance trends•Very difficult to beat a persistence forecast•Need: Data & tools to handle development & dissipation

Hours Ahead• Frontal bands, mesoscale bands, fog, thunderstorms• Rapidly changing, short lifetimes• Current sensors detect existence but not structure• Tools: satellite-based cloud advection and NWP• Need: Better forecasts of development & dissipation

Days Ahead•“Lows and Highs”, frontal systems•Slowly evolving, long lifetimes•Well observed with current sensor network•Tools: NWP with statistical adjustments•> ~ 10 days- climatology and climate trends•Need: better NWP performance & improved MOS

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Timelines of PV Forecasting RFP

7/16/2014RFP release

7/23/2014 Optional Notice of Intend to Propose Due

08/18/2014 Vendor Proposals Due

09/30/2014 Vendor Presentations

12/01/2014 Anticipated Contract Award

01/01/2015 Anticipated Contract Start Date

Proposed/ Current timeline. May be modified based on expected ability of respondents and ERCOT to complete necessary RFP evaluations.

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Data Flow and Dependencies of Renewable Production (PVGR) Potential Forecast

Renewable Production

Potential Forecast

Supervisory Control and Data

Acquisition (SCADA)

Data from PV Generation

Resources

RPP forecasts to QSEs

MISCertified Area

Market Information Systems (MIS)Secure Area

STPPF/PVGRPP

Mid-Term PV Generation Forecast

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PVGRs Telemetry Meteorological Data Points

Element Device(s) Needed Units Plane of Array Irradiance

Pyranometer or Equivalent

W/m²

Back Panel Temperature (Degree C)

Temperature probe for back panel temperature

⁰C

Air Temperature (Degrees Celsius)

Temperature probe & shield for ambient temp

⁰C

Wind Speed (Meter / Second)

Anemometer, wind vane and wind mast

m/s

Wind Direction (Degrees - Zero North 90CW)

Anemometer, wind vane and wind mast

Degrees

Barometric Pressure (hecto Pascals)

Barometer hPA

Plane of Array Irradiance (POA irradiance) is a measure of the total amount of solar energy that is available to an array, based the location of the array and the direction of the modules. POA irradiance is calculated at the module level, and averaged across modules to generate system-level values.

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PVPF Process InputsSource Data

Registration system1. Resource Parameters Resource Name Location of PVGR (latitude and longitude or equivalent for the center point of

PVGR) Location of the meteorological station (latitude and longitude or equivalent) Type (manufacturer/model) and number of PV panels Panel Power Rating Number of inverters Inverter ratings Tracking/Single or Dual Axis Tracking Tracker Manufacturer Tracker Model

1. Resource Commercial Operation Date

Energy Management

System (EMS)

1. Most recent Resource (PVGR) status with date/time 2. Most recent MW output of PVGR with date/time3. Most recent meteorological measurement from one meteorological station

with date/time4. Temperature and barometric pressure on the meteorological station

Telemetry value SCADA telemetry values are sent every 5 minutes from EMS to the PV forecast

service provider (all of these are Unit specific information with their Qualified

Scheduling Entities (QSE) mapping)1. MW Average2. Wind Speed3. Wind Direction4. Temperature5. Barometric Pressure6. Back Panel Temperature(*)7. Plane of Array Irradiance(*)8. HSL Average9. Num of Panels ON10. Num of Panels Off11. Num of Panels Unknown12. Curtailment Flag

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PV Forecasting RFP Requirement

• STPPF/PVGRPP will be delivered to ERCOT hourly, providing a rolling 48-hour hourly forecast of production potential for each PVGR or the entire ERCOT systems

• MTPVGF is an hourly forecast service for PVGR generation and the ERCOT system for the current day and the next 7 days.

• The performance of PV forecasting is evaluated based on both accuracy and reliability

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NMAE

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Progress on RFP

• More than 60 questions were clarified• 8 respondents received in response to

RFP• 6 proposals were selected for

presentation to narrow down the participants in the RFP

• ERCOT is identifying parties to provide presentations on their approach as the next step in commencing solar forecasting.

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Bill BlevinceManager Operations PlanningElectric Reliability Council of Texas, Inc.2705 West Lake DriveTaylor, Texas 76574

[email protected]