TEP-UNS Electric Load and Peak
Demand Forecast Overview
Jon M. BowmanSenior Supply-Side Planner
TEP and UES Resource Planning Workshop 1
Objectives
2
•Provide an overview of the load and peak
demand forecasts for TEP and UNS Electric
(Prior to additional DSM/EE adjustments)
•Discuss the key inputs, data sources, and
tools used in the forecasting process
•Identify key areas of uncertainty that have the
potential to significantly impact future
iterations of the forecast
TEP and UNS Electric Service Territories
3
Navajo
Sundt
Moenkopi
Peacock
Kayenta
Tucson
Generating Station
Coal Mine
Interconnection With Other Utility
Substation
Solar Station
TEP
UNS Gas
UNS Gas & Electric
UNS Electric
Service Areas
High Voltage
Transmission Lines
San JuanShip Rock
Four Corners
San Juan
Mine
Navajo
McKinleyMcKinley
Mine
Coronado
Springerville
Luna
Hidalgo
Greenlee
South
Vail
Valencia
Nogales
Davis
Mead
Black Mountain
KingmanKingman
Black Mountain
GriffithGriffith
N. Havasu Lake
Havasu
CityParkerParker
Saguaro
West Wing
Liberty
Palo Verde
PhoenixPinal West
ChollaFlagstaff
Lee Ranch
Yavapai
Prescott
MEXICO
NEVADA
UTAH COLORADO
NEW MEXICO
Lake
Havasu
City
Pinnacle
Peak
Methodology
4
•A monthly load forecast is prepared for each of the major
rate classes:
•Residential
•Commercial
•Industrial
•Mining
•Other (street lighting, etc.)
•The individual rate class level forecasts are aggregated to
produce the total load forecast for each company
•A monthly peak demand forecast for each company is
prepared based on:
•Anticipated load
•Historical relationship between consumption and peak
demand
Methodology, cont.
5
•Load forecasts for the residential and commercial classes
are based primarily on statistical models with inputs
including:
•Weather (e.g. HDD, CDD, Humidity, etc.)
•Demographic forecasts (e.g. population growth)
•Historical usage patterns
•Economic indicators
•Price response (TEP December 2008 rate increase first
in 13 years)
•Load forecasts for the industrial and mining rate classes
are prepared individually for each customer based on:
•Historical usage patterns
•Inputs from the customer (e.g. planned operational
expansions)
•Inputs from account managers
Data Sources
6
Data used in the forecasting process is collected from a
variety of sources including:
•IHS Global Insight
•The University of Arizona Forecasting Project
•Arizona Department of Commerce
•U.S. Census Bureau
7
TEP Forecast Summary
8
Residential41%
Commercial21%
Industrial24%
Mining11%
Other3%
TEP 2008 Sales by Rate Class
9
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
3.00%
290,000
300,000
310,000
320,000
330,000
340,000
350,000
360,000
370,000
2001 2002 2003 2004 2005 2006 2007 2008 2009
Resid
en
tial
Cu
sto
mer
Gro
wth
Rate
Resid
en
tial
Cu
sto
mers
TEP Residential Customer Growth
1
0
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
3.00%
28,000
29,000
30,000
31,000
32,000
33,000
34,000
35,000
36,000
2001 2002 2003 2004 2005 2006 2007 2008 2009
Co
mm
erc
ial
Cu
sto
mer
Gro
wth
Rate
Co
mm
erc
ial
Cu
sto
mers
TEP Commercial Customer Growth
11
5,000
6,000
7,000
8,000
9,000
10,000
11,000
12,000
13,000
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
GW
h S
ale
sTEP Reference Case Load Growth
Actual Load Forecast Load
AC
and
Appliance
Saturation
High
Population
GrowthIncrease in
Average
Home Size
~2.2% Average
Growth 1998 - 2008
~1.5% Average
Growth 2010 - 2020
~0.8% Average
Growth 2009 - 2010
Price
Impacts
(Rates,
PPFAC)Lower
Population
Growth
Structural
Changes
12
0
1,000
2,000
3,000
4,000
5,000
6,000
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
20
20
20
21
20
22
20
23
20
24
20
25
GW
h S
ale
sTEP Reference Case Load Growth by Segment
Actual
Projected
Residential
Industrial
Commercial
Mining
13
1,000
1,500
2,000
2,500
3,000
3,500
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
20
20
20
21
20
22
20
23
20
24
20
25
Pe
ak D
em
and
(M
W)
TEP Reference Case Peak Demand Growth
Actual Demand Baseline Forecast
Risks to Forecast
14
•Recession and Recovery
•Timing and strength of recovery
•Possible structural changes
•Copper price volatility (Mining)
•Impact of Technological Innovation
•Efficient lighting, appliances, etc.
•Plug in hybrids
•Volatility and Uncertainty in Demographic Assumptions
•Higher population growth than currently forecast
•Significant changes to persons/household, etc.
High levels of uncertainty in forecast assumptions
necessitate the consideration of multiple scenarios
15
High Growth
Plug in Vehicle
Reference
Case
DSM Target
2,000
2,200
2,400
2,600
2,800
3,000
3,200
3,400
3,600
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
20
20
20
21
20
22
20
23
20
24
20
25
Pe
ak D
em
and
(M
W)
TEP Peak Demand Scenarios
16
UNS Electric Forecast Summary
17
Residential45%
Commercial35%
Industrial/Mining20%
UNS Electric Estimated 2009 Sales Mix
18
1,000
1,200
1,400
1,600
1,800
2,000
2,200
2,400
2,600
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
20
20
20
21
20
22
20
23
20
24
20
25
Tota
l Sal
es
(GW
h)
UNS Electric Reference Case Load Growth
Actual Load Forecast Load
~2.3% Average Growth 2010 - 2020
High
Population
Growth
Mining
Expansion
Obscures
Res/Com
Slowdown
Lower
Population
Growth
19
0
200
400
600
800
1,000
1,200
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
20
20
20
21
20
22
20
23
20
24
20
25
GW
h S
ale
sUNS Electric Reference Case Load Growth by Segment
Actual
Projected
Residential
Industrial/Mining
Commercial
20
300
350
400
450
500
550
600
650
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
20
20
20
21
20
22
20
23
20
24
20
25
Pe
ak D
em
and
(M
W)
UNSE Reference Case Peak Demand Growth
Actual Demand Baseline Forecast
TEP and UES Resource Planning Workshop 1