SEWC Utility Advisory Group Bruce Rew, Vice President Operations

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Wind Capacity Installed by Year

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2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 0

2000

4000

6000

8000

10000

12000

14000

80 438 341 80 626 207 266 644 1176 837 561

2171

0 1146

3827

80 518 859 939 1565 1772 2038

2682 3858

4695 5256

7427 7427

8573

12400

Wind Installed Wind Capacity

Current MWs By Fuel Type

•  Wind Totals 12,400 MWs �  NDVer 6,634 MWs �  DVer 5,766 MWs

•  Solar 50 MWs •  Nuclear 2,635 MWs •  Natural Gas 35,692 MWs •  Coal 28,916 MWs

�  Generic Coal 21,368 MWs �  Lignite Coal 2,899 MWs �  Subbituminous 4,649 MWs

•  Hydro 3,427 MWs •  Other Fuel Types (Oil, Agricultural Byproducts, Municipal Solid

Waste) 1,659 MWs

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0

5000

10000

15000

20000

25000

30000

35000

40000

12400 6634 5766

50 2635

35692 28916

21368

2899 4649 3427 1659

MW's By Fuel Type

Renewables impacts to SPP •  Peak Wind Penetration level: 45.1% March 7, 2016

•  Peak instantaneous Wind output: 10,738 MW (36.9% pen.)

•  High impact on congestion and loading of the transmission system

•  Wind can cause capacity issues by �  Not showing up during times of high demand, contributing to

capacity shortages �  Showing up too high during times of low demand, contributing to

“Min Gen” issues

•  Short-term, intra-hour changes in wind also require reserves to maintain balance between generation and obligations

•  Wind forecast is crucial for SPP to have the right generation online at the right time, while maintaining the reliability and economic efficiency of the regional transmission grid.

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Operational Planning •  Multi-Day Reliability Unit Commitment (RUC)

studies starting 7 days out �  Identify potential capacity or transmission issues that may

need to be mitigated days in advance of the Operating Day

•  Day-Ahead RUC �  Run after Day Ahead Market (financial) results are posted �  Ensures adequate resource capacity for the Operating Day

•  Intra-Day RUC (same function as Day-Ahead RUC) �  Begin running the night before and throughout the

Operating Day �  Run at least every four hours, usually more frequently

•  *NEW* Short-Term RUC �  Run every 15 minutes, provides more granular look at

ramping obligations and transmission requirements

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7

OD - 7

Multi-Day RUC studies, utilizing Long- and Mid-

Term wind forecast

OD - 1 Operating Day

Real-Time

Day Ahead RUC, run after Day Ahead

Market results posted

Short-term wind forecast used in Pre-RTBM and

RTBM; estimates uncurtailed potential

Intra-Day and Short-Term

RUCs

Wind Forecast in SPP

High wind/low load capacity

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Dispatchable Range

At times we are using DVER wind to meet down-ramping obligation

RTBM redispatch of wind during down-ramping periods

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NDVER actual wind

Market dispatches more wind down after evening load peak, when system load is

dropping and we need to ramp down

DVER actual wind

Real-time usage of wind •  SPP implements a controlled release of DVERs

after curtailment �  Ramp constraint provides controlled release �  Allows the market to reevaluate before full release �  Provides a safety net for wind forecast error �  Optimize the reliable and economic solution with

many resources at once

•  DVERs can offer in to clear down-regulation service � Only a handful of DVERs have cleared Reg Down

in the past �  Allows wind farms to provide products other than

energy �  Helpful when system wind is increasing, load is

decreasing and we are constrained on down ramp for conventional fuel resources

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2015 Average Regulation Requirement contributors (Up direction)

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0

50

100

150

200

250

300

350

400

450

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

MW

Hour of Day

Average of Load Magnitude Componet Average of Load Variability Component

Average of Wind Magnitude Component Average of Wind Variability Component

“Wind Variability” component creates higher requirement on average during morning hours, as wind is typically ramping down during this time (expected use of Regulation Up during this time

November 26-28, 2015 Extreme Weather Event

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Timeline of Events Overview •  Operations Impacts Beginning at Approx. 4:30 on

11/26 �  Cold conditions and icing begin affecting wind resources �  Footprint wide output of wind resources begins to come

up significantly short of forecasted output �  Excess Capacity Reduced System Wide

•  Early Morning into Midday 11/27 �  Difference between 24 Hour Ahead Forecast and Actual

Wind Output greater than 6000 MW �  Significant Increase in Number of Self, IDRUC, and QS Unit

Commitments �  Limited Additional Capacity Available

•  Reduced Operational Impacts Continue on 11/28

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Impact on SPP’s Wind Forecast

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0

1000

2000

3000

4000

5000

6000

7000

8000

9000

SPP

Win

d M

W

Wind vs Forecast

Forecast 24 hours out Forecast 4 hours out Forecast 8 hours out Actual Wind

Storm moving in late Thursday 11/26

WF Outages/Derates in CROW

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0

500

1000

1500

2000

2500

3000

3500

11-26-15 00:00

11-26-15 12:00

11-27-15 00:00

11-27-15 12:00

11-28-15 00:00

11-28-15 12:00

11-29-15 00:00

11-29-15 12:00

11-30-15 00:00

11-30-15 12:00

12-01-15 00:00

OOS Derate

Managing the Event •  SPP Operators Adjusted for Loss of Resources/Capacity

Efficiently

•  SPP RUC Operators Committed Additional Resources Appropriately Given Information Available as Events Unfolded

•  WF Operators Informed SPP of Resource Status

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Lessons Learned and Potential Improvements Identified from Event •  Potential Icing Impacts as a Component of SPP’s Wind Forecast

•  Improving the Timeliness and Accuracy of WF Availability Information in CROW

•  Anticipating Capacity Needs in Preparation for Similar Events �  Day-Ahead Preparations �  Balancing Economic and Reliability Considerations

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SPP Wind Integration Summary • Market is adjusting to high levels of wind � Some LMP prices driven negative � Wind farms voluntarily curtailing due to price

• Operations responding to wind impacts � Forecasting continues to improve � SPP is blessed with large number of quick start units � DVER policies and experience from EIS market greatly

helped in Integrated Marketplace

• Wind futures… � Wind capacity continues to increase, expect another

4,000 MW within 2 years � Expect to hit >50% penetration level in April 2016 � Studying higher wind penetration level impacts to

maintain reliable operations

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Bruce Rew, PE Vice President, Operations brew@spp.org 501-614-3214