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John J. ContiActing Director
Office of Integrated Analysis and Forecasting
Prepared for the Energy Technology System Analysis Program (ETSAP)
Florence, Italy
November 24, 2004
System for the Analysis of Global Energy (SAGE):
Electric Sector Enhancement
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SAGE Background• A MARKAL-based energy model utilizing the VEDA software
for model creation and results analysis.• Produces integrated energy projections through 2025 for 15
regions of the world.• EIA’s International Energy Outlooks have been based on
SAGE model results since 2003.• Uses a time-stepped approach to address foresight and other
modeling issues (i.e., learning, market sharing, etc).• Each year a number of model enhancements are scheduled
(some are even implemented). • One key improvement this year has been a reformulated electric
sector.
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Electricity Sector Enhancement• Purpose: to increase model flexibility in choosing
between alternative fuel/technology combinations in response to various changes in inputs to address alternative policies, energy market conditions, or technological characteristics. – Allow model to economically choose to build and operate
appropriate mix of electricity technologies• Maintain selected external constraints to allow for regional
differences and assumed must run/out of merit order generation and capacity selection (e.g., renewable portfolio standards, etc.)
– Allows for the appropriate economic valuation of carbon allowances in electricity sector and flexibility to react to carbon shadow prices or constraints.
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Elements Modified• Improved the technological
characterization of existing and new capacities.
• Better representation of peaking, intermediate, and baseload demand
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Concerns with Previous SAGE Electricity Model Formulation
• Model builds and operates large amounts of baseload technologies
• Constraints required to force proportional generation by other fuels
• Model dispatch and capacity choice decision were not based on the technological specifications, capital cost parameters, and fuel costs
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Concerns with Previous Model Formulation (cont.)
• Annual electricity demand is segmented into 6 periods:– Summer, Winter, and Intermediate– Day and Night
• Electricity capacity expansion and dispatch decisions meet demand varying by the above 6 seasonal/diurnal segmentations.
• The 6 segment load demand curve representation is too flat to adequately capture the comparative economics of peaking and intermediate technologies
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New SAGE Electricity Model Formulation
• Changed “seasonal/time of day” framework to “load duration curve” concept
• Developed mapping of typical end use load for each end use to aggregate load.
• By region, selected dominant end use load as basis for establishing time slots for load duration curve slices (e.g., industrial world’s peak dominated by cooling load)
• Stayed within default 6 slice limit.
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New SAGE Electricity Model Formulation (continued)
SAGE load slices
0
100
200
300
400
500
600
700
800
0 2000 4000 6000 8000
time
Gw
Demand met with Peaking capacity
Demand met with Intermediate
Base load
• Demands mapped to load slice based on end use demand’s proportion of load slice • Load slices are organized around load duration curve
1st Slice First 2% of hours
2nd Slice Next 10% of hours
3rd Slice Next 22% of hours
4th Slice Next 22% of hours
5th Slice Next 22% of hours
6th Slice Next 22% of hours
Peak time slice Intermediate time slice
8760
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Original vs. New SAGE Electricity Load Curves
USA Alternative LDCs
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
- 0.0
5
0.1
0
0.1
5
0.2
0
0.2
5
0.3
0
0.3
5
0.4
0
0.4
5
0.5
0
0.5
5
0.6
0
0.6
5
0.7
0
0.7
5
0.8
0
0.8
5
0.9
0
0.9
5
1.0
0
Fraction of Year
Gig
aw
att
s (
Th
ou
sa
nd
s)
Seasonal Day/Night New LDC
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Model Results Summary
• Peaking facilities (such as turbines) are built to operate in the 1st (i.e. peak) slice;
• Intermediate facilities (such as combined cycle) are built to operate primarily in 2nd slice.
• Baseload facilities (such as coal or combined cycle) are built to operate in the four baseload slices.
• First, we will look at the capacity expansion decision, followed by the dispatch decision. This is based on the U.S. region for the year 2025.
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Electric Sector CapacityComparison of Dispatch
Peak + Reserve
0
200
400
600
800
1,000
1,200
Seasonal/Time of Day
Load DurationCurve
GW
Oil
Gas
N GT
N CC
Coal
N Coal
Nuclear
Renew
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Electric Sector Capacity by SegmentDispatch Using Seasonal/Time of Day Method
0
200
400
600
800
1,000
1,200
Peak +Reserve
Slice 1 Slice 2 Slice 3 Slice 4 Slice 5 Slice 6
GW
Oil
Gas
N GT
N CC
Coal
N Coal
Nuclear
Renew
Dispatch Using Load Duration Curve Method
0
200
400
600
800
1000
1200
Peak +Reserve
Slice 1 Slice 2 Slice 3 Slice 4 Slice 5 Slice 6G
W
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Comparison of Total GenerationComparison of Total Generation
0
1,000
2,000
3,000
4,000
5,000
6,000
Seasonal/Time of Day
Load DurationCurve
bil
lio
n k
Wh
Oil
Gas
N GT
N CC
Coal
N Coal
Nuclear
Renew
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Generation by Segment
Generation Using Load Duration Curve Method
0
200
400
600
800
1,000
1,200
1,400
Slice 1 Slice 2 Slice 3 Slice 4 Slice 5 Slice 6b
illio
n k
Wh
Generation Using Seasonal/Time of Day Method
0
200
400
600
800
1,000
1,200
1,400
Slice 1 Slice 2 Slice 3 Slice 4 Slice 5 Slice 6
bil
lio
n k
Wh
Oil
Gas
N GT
N CC
Coal
N Coal
Nuclear
Renew
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Electricity Reformulation Benefits
• Appropriate model capacity expansion and dispatch is not forced via additional constraints.– Improved model application for policy analysis– Electricity price forecast more reasonable– Electric sector results respond to changes in
endogenous variables such as relative fuel prices.
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Other SAGE Activities
• In progress:– Improved market share algorithm– Enhanced discount, interest, investment hurdle rate
methodology– Formalized version control, issue tracking, and
software installation.
• Planned:– Kyoto Scenario Analysis