Energy Systems
Modeling at ERC
The SA TIMES Model
Overview of Modeling
Demand Sectors (commercial and agriculture omitted from diagram)
Energy Resources/Import and Exports
Import/export
(elc, oil, gas)
Renewable
energy resource
potential
Fossil fuel
reserves
Supply Technology
Future coal/gas
supply
technologies
Future liquid
fuel supply
technologies
Future power
generation
technologies
Existing
coal/gas supply
system
Existing liquid
fuel supply
system
Existing power
system
Base Year Energy
Balance
MARKAL/TIMES
optimization
energy model
(GAMS with CPLEX
solver)
Residential
sector future
technologies
Industrial sector
future
technologies
Transport
sector future
technologies
Residential
sector baseyear calibration
Industrial sector
base-year
calibration
Transport
sector baseyear calibration
Residential
sector Demand
projections
Industrial sector
Demand
projections
Transport
sector Demand
projections
Economic Analysis
Policy objectives/constraints
Energy security
objectives
Environmental
objectives,
taxes
Socio-economic
growth
objectives
Socio-Economic
Variables (GDP,
Population)
Results Analysis
Inputs to optimization model
Outputs from optimization model
Intermediary information flow
Investment
Schedule/Plan
Imports, exports,
consumption,
production, Emissions
System costs,
energy costs
Components of a MARKAL/TIMES
model
Components of an Energy System Model
* Energy system
topology & organization
RES
150
125
* Numerical data
100
Time Series
G 75
W50
h
25
0
1970
* Mathematical structure
– transformation equations
– bounds, constraints
– user defined relations
* Scenarios and strategies
1975 1980 1985 1990 1995 2000
2005 2010 2015 2020
PBHKW _ S   BHKW  PCoal _ BHKW
OBHKW _ CO    PCoal _ BHKW
2
QBHKW _ H   2 _ BHKW  PCoal _ BHKW
GAMS Model
Cases
Simple Reference Energy System
Energy model components
• Made up of 2 simple components:
– Energy Carriers (e.g. fuels, demand)
– Technologies (e.g. Light bulb, power plant) all
characterized in the same way:
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Input and Output Carrier
Efficiency
Investment Costs per unit of capacity
Annual Activity Costs
Existing Capacity
Annual Availability
Expected Life
Emissions
Useful energy demand
• Calculated using spreadsheets
• Based on assumptions
– Useful energy calculated for base year
– Projected into future
• Affected by
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GDP assumptions
Structure of the economy
Changes in per capita income
Assumed income distribution, electrification etc
Sectors
Sector
Disaggregation
Driver
Agriculture
By end use, irrigation, transport etc
Agriculture GDP
Residential
High, medium and low income/ electrified and
non-electrified
POPULATION, Household income
By end use, cooking, lighting etc
Commercial
By end use, lighting, HVAC, etc
Commercial GDP, building stock
Industrial
By sector, Iron and Steel, Pulp and paper etc
Sectoral GDP
By end use, thermal fuel or electricity (compressed
air, cooling, motive, etc
Transport
Air, Freight, passenger, pipeline
By end demand, passenger km, ton km
By end use, diesel car, petrol car, taxi etc
Transport GDP, Population and
household income
Variation of the Load (electricity)
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20 Time-slices
Year divided in 3 seasons
Each season represented by 2 typical days
Season 1 and 3 (summer), each day is broken
up into 3 parts (night, day, evening)
• Season 2 (winter) week day is broken up into 5
parts (night, morning, afternoon, evening,
peak)
Other elements
• Emissions:
– Emissions coefficient/energy carrier
– Emissions Tax
• Constraints:
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Committed build plans
Resource limits
Mode shares
Fuel shares
Policy Objectives (e.g. CO2 limit)
Model Outputs
• Reported globally:
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Total Costs
Total tax/subsidy
Total Investments
…
• Reported for demands each year:
– Actual energy demand met
– Marginal Price (Shadow price/cost of supplying one extra unit of demand)
• Reported for each energy carrier each year:
– Imported/exported
– Mined
Model Outputs (Continued)
• Reported for technologies each year:
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Fixed costs
Capacity Level and Marginal
Capacity Unused
Fuel Used
Investment Costs
Investment Levels and Marginal costs
…
• Reported for emissions each year:
– Emission Levels
• Reported for tax/subsidy each year:
– Tax/Subsidy
The SAGE Model
• Calibrated to a 2005 SAM (Arndt et al., 2011)
– 54 industries and 46 commodities
– 7 factors of production (4 education-based labour groups; energy and nonenergy capital; agricultural productive land)
– 14 household groups based on per capita expenditures
– Energy Supply Sector disaggregated
• Resource constraints
– Upward sloping labour supply curves for less-educated workers
– Sector Specific capital and endogenous capital accumulation
• Macroeconomic closures
– Fixed current account with flexible real exchange rate
– Savings-driven investment
• Model has already been used by Treasury to look at
some CO2 tax scenarios and recycling options
SAGE Model (continued)
• Previous Runs of SAGE model with Power
sector production shares and investment
The CGE-TIMES Link
- Simple Extrapolation of
sectoral and income
growth, used to recalculate useful energy
demand.
-GDP and sectoral
growth
-Household income
growth
- Electricity Generation
Shares
- Investment
- [Electricity
production costs]
Sectoral Linkage
The CGE-TIMES link continued
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The Idea is to replicate IRP/IEP process in TIMES
Fix committed build
See how the economy responds
Adjust forecast and update investment plans
Re-iterate