Wind Integration in ERCOT

Wind Integration in ERCOT

Beth GarzaDirector, ERCOT IMMbgarza@potomaceconomics.com512-225-7077

EIA Conference

June 4, 2018

Thoughts on ERCOT’s Wind Generation Experience

• More wind, more wind, more wind• Better reliability metrics• Reduced ancillary services requirements

2

Geography

3

H

Mexico

D

SA

ERCOT Annual Energy by Fuel Type

4

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Annu

al G

ener

atio

n M

ixOther

Natural Gas

Wind

Coal

Nuclear

Wind Output and Estimated Curtailment

5

8.4%

17.1%

7.7%

8.5% 3.8%1.1%

0.5%

1.0%

1.6%

2.5%

0

10

20

30

40

50

60

70

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Win

d Pr

oduc

tion

& C

urta

ilmen

t (TW

h)

Estimated Curtailment

Output

More wind producing more

6

0%

5%

10%

15%

20%

25%

30%

35%

40%

0

5

10

15

20

25

2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Annu

al C

apac

ity F

acto

r

Inst

alle

d W

ind

Gen

erat

ion

(GW

)

Installed Wind Capacity

Annual capacity factor

2017 Unit Specific Wind Generation Capacity Factor

7

0%

10%

20%

30%

40%

50%

60%

Capa

city

Fac

tor

InService Year

Coastal Panhandle All Other Wind

Improved Reliability Metrics

8

Declining Requirements for Ancillary Services

9

0

1

2

3

4

5

6

2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Rese

rve

Qua

ntiti

es -

GW

RegDown NonSpin Responsive RegUp

Key Enablers

• Common carrier model for Transmission• Centralized forecasting of wind output

– for every wind generator– ramp events

• Real-time output variations accommodated

10

ERCOT Transmission

• All loads pay for all transmission • Generators are not required to make any transmission

investment past their step-up transformer• Public policy choice to build out transmission system in

advance of need– CREZ investment - $7B

11

$0

$10

$20

$30

$40

$50

$60

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

Rate

($ p

er k

W -

year

)

Transmission Costs

12

$0.0

$0.5

$1.0

$1.5

$2.0

$2.5

$3.0

$3.5

$4.0

0

10

20

30

40

50

60

70

80

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

Annu

al T

COS

($Bi

llion

)

Aver

age

4CP

Load

(GW

)

Indicative – Not Actual

Transmission and Energy costs

13

0

1

2

3

4

5

6

7

8

9

0

10

20

30

40

50

60

70

80

90

2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

$ pe

r MBt

u

$ pe

r MW

h

RT Load weighted Avg price Average transmission cost Gas

Indicative Transmission CostsNot Actual

ERCOT Wind Forecasts

• Hourly forecast of wind production potential for each Wind-powered Generation Resource (WGR) updated hourly, for next 168 hours. (STWPF)

• Determine probability distribution of the hourly production potential from all wind-power in ERCOT for each of the next 168 hours. (TEWPF)

• WGR provide turbine availability via outage scheduler

14

ERCOT Wind Forecasts - WGR requirements

• Install and telemeter to ERCOT site-specific meteorological information necessary to produce the STWPF and TEWPF forecasts.

• ERCOT requires the following data be provided from each WGR every five minutes:

15

MW AverageWind SpeedWind DirectionTemperatureBarometric Pressure

HSL AverageNum of Turbines OnNum of Turbines OffNum of Turbines UnknownCurtailment Flag

Accommodating variable output

• ERCOT dispatch executes every 5 minutes• WGR High Sustained Limit (HSL), when not curtailed, to be

telemetered as equal to the WGR’s current meter reading• When curtailed, WGR’s receive a curtailment flag from

ERCOT along with their Base Point (dispatch level)• When WGR is curtailed, the HSL to be telemetered is the

expected output, but for the curtailment• WGR ramping when curtailed limited to 20% per minute,

unless installed before 2009 and have a good excuse

16

Negative prices

17

0

100

200

300

400

500

600

700

800

900

1000

2011 2012 2013 2014 2015 2016 2017

Hou

rs

WEST Only ERCOT Wide Other

In Summary

• ERCOT’s experience– More wind, more wind, more wind– Better reliability metrics– Reduced ancillary services requirements

• Enablers– Common carrier model for Transmission– Centralized forecasting of wind output– Real-time output variations accommodated

18