4/23/2019

Dispatchable Intermittent Resources (DIR) Wind Forecasting

Workshop

1

• Purpose:

• Discuss forecasting accuracy importance, observations of accuracy and upcoming rule changes

• Key Takeaways:

• Settlement rule changes may result in units relying more on MISO’s wind forecast

• Market Participants should aim to submit accurate forecasts

• MISO has the ability to monitor wind forecasting accuracy

2

Executive Summary

Background

3

Wind capacity in MISO is approaching 20 GW,

Wind peak is 16.3 GW set on March 15, 2019

Wind portfolio expected to increase to 29 GW by 2023

To dispatch wind generation, MISO needs a wind forecast

Accurate wind forecasts are required to maintain reliability and market efficiency

MISO’s forward and real-time commitment is

highly dependent on intermittent forecasts

4

Market Commitments

Forward Commitment Process >16

hours

Intra-day Commitment Process >4

and < 16 hours

Look Ahead Commitment

<3 hours

10 Minute Real Time

Market

Medium Term Hourly

Renewable forecast

(updated hourly)

Short Term 5 minute

Renewable forecast

(updated every 5 minutes)

Market Participants Intermittent Resource

Forecast Submittal

5

• These forecasts are used to satisfy the Must Offer Requirements for the Day Ahead Market

• The hourly wind forecasts are not used in MISOs Forward commitment processes

Hourly Wind Forecasts

• 5 minute forecasts are used by MISOs Unit Dispatch System as an economic maximum for the resource for the next dispatch interval

5 Minute Wind Forecasts

Renewables are intermittent generation resources

part of the generation supply

6

Additional commitments

may be made if the

forecasted wind is less than

actual.

Too much generation may

materialize if more wind is

generated than forecasted.

Forecasting accuracy

impacts the equilibrium point

Q: Why is wind forecast accuracy so important?

Commitment ensures the committed

generation is able to meet the

expected load

Accurate wind forecasts will

result in market efficiency

To balance market and

reliability, MISO uses less regulating

reserves and offsets due to accurate wind

generation forecast

7

One objective of this workshop is to align a common

understanding of forecast accuracy among all participants

DIR resources require a forecast for the next

dispatch interval

8

Persistence Forecast

Wind Generation Forecast

Persistence & Forecast

Actual Wind Unit outputOR OR

The remainder of the workshop will discuss:

9

Market Participants open forum

January 2019 wind forecasting event and lessons learned

Wind Forecasting Process Overview to ensure Market Participants know about MISOs wind forecasting process and monitoring capability

MISO Settlement Rule Changes, effective on May 1, 2019 will change DIR incentives

MISO Settlement Rule Changes

Background on Settlement Rule Changes

11

MISO has worked with Market Participants and IMM to develop new settlement rules and incentivize generators to

follow dispatch instructions in the Real Time Market

Dispatchable Intermittent Resources (DIR) settlement rule changes are proposed

FERC has approved MISOs settlement rule changes effective May 1, 2019

A review of the Settlement Rule changes specifically to DIR is presented

Settlement Rules Current State

- Market Participant (MP) submit Forecast

- MISO Forecast vs State Estimator (SE) Value

Forecasts Set the Economic Maximum Parameter

MISO has a current set of charges in place when violations occur

12

DIR Uninstructed Deviation Changes

13

- Excessive/Deficient Energy evaluated for every interval

-Thresholds based on 8% of Setpoint

-Price Volatility Make Whole Payment ineligibility

-Excessive Energy Price is Offer Price or Real Time Locational Marginal Price

-Excessive/Deficient Energy evaluated when dispatched

below and using MISO’s forecast

-Thresholds based on a factor of ramp rate or 12% of

Setpoint

-Price Volatility Make Whole Payment based on

performance

-Excessive Energy Price is a % of Real Time Locational

Marginal Price

BEFORE AFTER

Participants will receive an increased amount of

Excessive Energy Credits because of the price change

Will the uninstructed deviation changes

impact my wind forecast submittal?

14

Some Market Participants have already switched over to MISOs DIR forecast

Market Participants have expressed interest in learning more about MISOs DIR forecast

The new rules provide flexibility for Market Participants

Continue to submit forecastsStart Relying on MISOs DIR

Forecasts

Wind Generation Forecast Process

16

Wind Capacity Growth in MISO

1112

2462

4861

7625

9221

10601

1227113035

13726

15026

16319

17719

19251

22271

23921

25521

27121

28721

0

5000

10000

15000

20000

25000

30000

35000

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

MW

YEAR

Intermittent Resources

Dispatchable

Expected to follow dispatch

instructions

5 min forecast used as

Economic Max

Non Dispatchable

MISO doesn’t send dispatch instructions

State Estimator

value is used

17

Dispatchable Intermittent Resources (DIR)

participate similarly to traditional resources

Supply Energy, not Operating Reserves

DIRs can offer with the Commit Status in Day Ahead and Real Time markets

Dispatch Status can be Self-Schedule

Primary difference: Forecast is the source of Economic Max

18

How Does MISO Build A Wind Forecast?

19

Data is supplied to a

model

Live Dynamic Data (Actuals)

Numerical Weather Predictions (NWP)

Static Information

Forecast is

Produced

MISO Short Term Wind Forecast gets

updated with every dispatch interval

20

Short term prediction

adapts prediction to

current conditions

By building multiple Numerical Weather

Prediction models, a deterministic wind forecast

is established based on ensemble forecasting

21

0

2000

4000

6000

8000

10000

12000

14000

16000

MW

--Time series --

Series1 Series2

Series3 Series4

NWP1

Final

NWP2

NWP3

Static information: submitted as part of Attachment

B and aligned with MISO quarterly model updates

Required Commercial Pricing Node (CP Node) information

Centralized geographic coordinates

(Latitude and

Longitude)

Hub Height in meters

(measured from the ground level)

Maximum installed

capacity in MW

High wind speed cutoff

threshold

High/Low temperature

cutoff threshold (in

degrees Fahrenheit)

Number of Turbines

Operational Date

22

Market Participants have flexibility to submit

wind forecast, or use MISO’s wind forecast

Market Participant Wind Forecast will be used unless:

• Submitted forecast is above DIR feasibility limit plus a technical margin, or

• No wind forecast is updated for more than 30 minutes

MISOs forecast will be used:

• When Market Participant choose to not submit/update forecast

• Market Participant technical margin check fails

• MISOs dispatch instruction is the Maximum(State Estimator, MISO wind forecast)

The wind forecast becomes the Economic Maximum for the wind unit and is used for the next dispatch interval

Market Participants can go back and forth between submitting their own forecast or use MISOs

23

Accuracy is impacted by wind farm behavior

MISO wind forecast accuracy is dependent on the wind farm. MISO expects

the DIR wind unit to:

Follow dispatch set point

Update outage information and derates

Provide Testing and Commercial Operational

Date notifications*

Provide Valid ICCP data

24 * Improvements here are needed

Example 1:Unit providing forecast which is

inconsistent with outage submitted

25

> 80 MW

Example 2: Suspect ICCP prevents actual generation

capability of the wind unit to be forecasted

26

MISO’s Benchmark for Wind Accuracy

Wind Forecasting Characteristics

What forecast methodology leads to smallest forecast

errors?

What does MISO use as a forecast

methodology?

Why did MISO adopt a combined approach?

• Industry agrees that nothing beats persistence

• MISO uses the maximum of persistence or the forecast

• To allow DIR units the opportunity to generate more than just persistence

28

Market Participant submittal of reasonably

accurate forecast

29

0

20

40

60

80

100

120

140

160

180

MW

<-Time line ->

MP Forecast Actual gen

30

Wind forecast that are consistently high impact

MISOs operations

MISO developed a wind forecast accuracy

benchmark

Selected a 45 day sample data, and evaluated how the Market Participant forecasts compared with each other

Mean Absolute Error (MAE): a value tells us how big of an error we can expect from the forecast on average in MW.

Mean Absolute Percentage Error (MAPE): calculated as the average percentage error for each time period minus actual values divided relative to maximum capability.

MISO also compared the accuracy of MISOs forecast to that of Market Participants: Overall MISO forecast tends to be more accurate

31

32

6.1

4.39

2.08

0.93

4.87 5.02

2.78

2.03

> 200 100 ~ 200 50 ~ 100 <50

MA

E (

MW

)

Unit Size

MAE MISO 45 Days MAE MP 45 days

Mean Absolute Error: Comparing MISO and market

participant 5 min forecasts versus actuals

# of Units: 12 39 24 17

Mean Absolute Percentage Error: Comparing

MISO & Market Participant 5 min forecasts vs

actuals

33

2.57

3.42

2.813.13

2.1

3.96 3.75

7.36

> 200 100 ~ 200 50 ~ 100 <50

MA

PE

(%)

PMAX Range

MAPE MISO 45 Days MAPE MP 45 Days

# of Units: 12 39 24 17

Wind Benchmark Accuracy Observation

34

Market Participants tend to produce better forecasts when units have a PMax > 200 MW

Market Participant forecasts tend to have an error on the positive side (positive bias)

MISO has noticed improvements in forecast from Market Participants contacted due to the study

MISO cares about wind forecast accuracy

• MISO will perform a study quarterly and notify performers whose accuracy lies outside the band

• Market Participants can check MISO forecast and compare for accuracy

MISO wind forecast accuracy

35

MISO’s Forecast Improvements

Recent Improvements to wind forecast:

Wind Monitoring and Alerting

Created monitoring

and reporting

capability of wind

forecast accuracy

Started issuing e-mails to

participants with errors outside the

band

Some Market

Participants have

switched to MISO’s forecast

Icing report, best case, worst case forecasts

help MISO’s

operations

37

Recent Improvements to wind forecast:

Model and Data Transfer

Added additional numerical weather model

Fine tuned forecast algorithm to reduce time lag, improved accuracy

Forecast file exchange improvements, reducing processing time

38

MISO’s forecast had some lag issues which

was impacting the forecast accuracy

39

0

20

40

60

80

100

120

140

160

180

MW

<--Time line-->

MISO Forecast Actual gen

Accuracy after Lag improvement: Sample

Units

40

0

1

2

3

4

5

6

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

MA

PE

Wind Farm Unit

Accuracy Improvement: Before and After

Before After

Upcoming Improvements: Short Term

Aligning forecast time to dispatch time

Due to Uninstructed Deviations rule changes, MISO expects market participants to switch to MISOs forecast

Updating Wind Farm Operational Characteristics will allow MISO to generate more accurate forecasts

Jump start of the wind forecast once the farm has been off, workaround is manual

41

Upcoming Improvements: Longer Term

Notifications of Commercial Operation dates of wind farms are lagging creating forecast inequalities

Evaluate theoretical approaches to help improve wind forecasting accuracy

Evaluate the impact of uninstructed deviation changes

42

January 30-31, 2019Maximum Generation Event

• Purpose:

• Provide insight into how

operations and wind forecasting

were affected during these dates

• Key Takeaways:

• Operations were heavily affected

due to record low temperatures

in the MISO footprint

• The event showed areas of

improvement are needed in the

wind forecasting process

44

Wind Generation During the Event

45

-30

-25

-20

-15

-10

-5

0

0

2

4

6

8

10

12

14

16

15161718192021222324 1 2 3 4 5 6 7 8 9 101112131415161718192021222324 1 2 3 4 5 6 7 8 9 101112

Te

mp

era

ture

(F

°)

GW

Hour Ending

Actual Wind Generation Day-Ahead Wind Forecast

North-RT Temperature North-DA Temperature

January 30 January 31January 29

Unplanned Generation Outages

46

MISO North/Central Region Unplanned* Outages (GW)

Coal Gas Wind Other Total

Installed Capacity (PRA cleared plus uncleared

internal MISO generation that

qualified for the 18-19 PY)

48.4 31.9 14.2 18.2 112.7

January 2910.3

(21%)

6.3

(20%)

1.3

(9%)

2.2

(12%)

20.1

(18%)

January 3010.3

(21%)

10.8

(34%)

4.0

(28%)

4.5

(25%)

29.6

(26%)

January 319.3

(19%)

11.9

(37%)

2.7

(19%)

5.0

(28%)

28.9

(26%)

Next Steps

47

Cold weather cutoff data gathering

Improve inputs to wind forecast to account for low temperatures

Evaluation of extreme events

Continued collaboration and readiness

Key Takeaways and Discussion

Recap

49

DIR Wind Workshop

Settlement Rule

Changes

Wind Generation Forecast Process

Ways to Impact the

Wind Forecast

MISOs Benchmark

for Wind Accuracy

MISOs Forecast

Improvement

Maximum Generation

Event

Questions?

Appendix

Relevant Definitions

52

Forecast Maximum Limits: the Maximum MW Level at which a Dispatchable Intermittent resource may operate

Dispatchable Intermittent Resource: A Generation Resource whose Economic Maximum Dispatch is dependent on forecast- driven fuel availability.

Dispatchable Intermittent Resource Feasibility Limit: The Maximum MW Level at which a Dispatchable Intermittent resource may operate and/or be scheduled, subject to any technical margin(s) as may be provided in the Business Practices Manual.

References

53

Business Practices Manual 025: Operational Forecasting Section 5

Business Practices Manual 002: Energy and Operating Reserve Chapter 5

Tariff: Module C, sections 39.2.5.c and 40.2.5.e

Have a question or a comment?

54

General forecast related questions should be sent to: ClientRelations@misoenergy.org

Issues with operational forecast contact the central, north, or south generator and balancing authority operator

Questions related to forecast access and portal should go to ITNOC at 317-249-5555

Wind Generation Forecast Process

55

Wind Monitoring and Alerting System:

Automated monitoring system that checks the forecast quality every 5 minutes for more than 200 wind and solar units and

sends out alerts if any unit fails validation

Track errors and provide a platform to improve forecast

accuracy

56

Wind Alerting System: Validation Criteria

Triggers for 5min

Wind Forecast Errors!

EcoMax deviation

wind unit does not

follow dispatch

signal

Wind ICCP Measurement

is Stale

Forecast is More Than

PMax

Actual Output is

More Than 110% of PMax

57

Icing Report: Best Case/Worst Case

Scenarios

58