Energy –Environmental
Inter-Model Comparison Exercises:
Past, Present and Future
John P. Weyant
Director of the Energy Modeling Forum andProfessor of Management Science and Engineering
Stanford University
Stanford, California
ALPS International Symposium 2012
"Addressing Climate Change Harmonized with Sustainable Development“February 7th, 2012
Nadao Hall
Shin-Kasumigaseki Building
Tokyo, Japan

Outline• Introduction• EMF objectives, design principles & studies• Lessons learned from past model intercomparison studies– Things that worked well
– Things that could be improved– Current trends in inter-model comparisons• Suggestions for the future of modelcomparisons, diagnostics and assessment

Energy Modeling Forum Objectives• Understand model differences• Understand strengths and weaknesses ofexisting models/methodologies• Identify useful information and insights forcorporate planning and government policy
making• Identify high priority areas for development of
new data, analyses, and modelingmethodologies

EMF Design Principles• Broad participation• Focus on model comparisons• Policy relevance• Decentralized analysis• Wide dissemination of results

EMF Studies
EMF 0: CONAES Modeling GroupEMF 1: Energy and the Economy
EMF 2: Coal in Transition
EMF 3: Electric Load Forecasting
EMF 4: Elasticity of Energy Demand
EMF 5: U.S. Oil and Gas Supply
EMF 6: World Oil
EMF 7: Macroecon. Impacts of Energy Shocks
EMF 8: Industrial energy Demand
EMF 9: North American Natural Gas
EMF 10: Electric Markets and Planning
EMF 12: Carbon Emission Reductions
EMF 11: International Oil
EMF 13: Markets for Energy Efficiency
EMF 14: Integrated Assessment of Climate Change
EMF 15: Markets for PowerEMF Studies (Continued)
EMF 16: IA of Climate Change: Post-Kyoto
EMF 17: Prices/Emissions in Restructured Elec. Mkts.
EMF 18: Trade Dimensions of Climate Policy
EMF 19: Technology and Climate Policies
EMF 20: North American Natural Gas
EMF 21: Multi-Gas Greenhouse Gas Mitigation
EMF 22: GHG Gas Transition Scenarios
EMF 23: World Natural Gas Markets & Trade
EMF 24: US Technology Strategies for GHG Mitigation
EMF 25: US Energy Efficiency Potentials
EMF 26: Energy System Impacts of Shale Gas
EMF 27: Global Tech. Strategies for GHG Mitigation
EMF 28: EU Technology Strategies for GHG Mitigation
EMF 29?: International Trade & GHG Mitigation

Lessons Learned From Past
Inter-Model Comparison Studies;Things That Worked Well• Timing is everything; address issues that areimportant and for which enough different models exist.
• Insights, not numbers .
– Insights about markets.
– Insights about policies.
– Insights about model comparisons.
– Insights about the adequacy of current methods.

• Tension between diagnostics and policy analysis.
• Importance of study groups.
• Forecasting in perspective.

Market Insight #1
Change in electricity consumption projections with 10% priceincrease relative to the reference case. Source: EMF 3

Market Insight #2
Model Means for Average U.S. Wellhead Price
Source: EMF 9Policy Insight #1
Projected 2010 Carbon Tax Under the Kyoto ProtocolCommitments and Various Emissions Trading Assumptions

Policy Insight #2
Where & When Flexibility in Stabilizing CO2
Concentrations at 550 ppmv
Source: UNFCC-EMF Oslo Workshop (August 1997)
10(Net Present Value Discounted at 5% Real)
8Mini-CAM

Trillion 1990 US Dollars

6MERGE

CETA

non-Annex 1
EEFSU

4OECD

20
WGI-no WGI- WRE- WREtrade
trade no trade trade-2

WGI-no WGI- WRE- WREtrade
trade no trade trade

WGI-no WGI-tra WRE- WREtradede no trade tradePolicy Insight #3

CO2-e Concentration - Kyoto Gases Only (ppmv)

Without mitigation, CO2-e concentrations will quickly
pass the three long-term goals.
Source: EMF 22
1600
1500
1400
1300
1200
1100

Radiative forcing fromKyoto gases in 2010: ≈445 CO2-e

1000
900
800
700
600
500

650 CO2-e:
2040 to 2060

400
300
200
1000
2000

450 CO2-e:
Now to 2015
2010

2020

2030

550 CO2-e:2025 to 2040
2040

2050

2060

2070

2080

2090

Note: CO2e Now Growing at 3.5 to 4.5 ppmv per year

2100

Policy Insight # 4
Relative Importance of New Equipment EfficiencyImprovements in the Total Decline in U.S. Energy
Intensity, 1990-2010. Source: EMF 13

Policy Insight # 5
Annex I Leakage in the No Emissions Trading
Case With Respect to the Reference
Source: EMF 18

Leakage in %(Increase in Non-Annex I Emissions/Reduction in Annex I Emissions)

40
35
30
2010

25
2020

20203015
10
5
0

G-CubedAIM

Gemini-E3

GTEM

ModelWorldScan

MS-MRT

MERGE4

Inter-Model Comparison Insight #1
Aggregate total demand elasticity estimates.
Source: EMF 4

Inter-Model Comparison Insight #2
Aggregate elasticity of substitution calculatedusing the outputs for the base case and the basecase with constraints. Source: EMF 1

Models Need Improvement Insight #1
Distributed Generation and T&D Constraints• EMF 10: Electric Markets and Planning– IPP grid integration• EMF 15: Markets for Power– More competitive electricity markets• EMF 17: Prices/Emissions in Restructured Elec. Mkts.
– Env. Impacts of competitive electricity markets• EMF 24: US Technology Strategies for GHG
Mitigation?
– Grid integration of renewables

Models Need Improvement Insight #2
Carbon Permit Price (2000$USD/tC) in CO2-Only(solid) and Multigas (dashed) Scenarios
Source: EMF 21
1000

800

600

40020002000

2025

2050

2075

2100

AIM
AMIGA
COMBATEDGE
FUND
GEMINI-E3
GTEM
IMAGE
IPAC
MERGE
MESSAGE
MiniCAMSGM
WIAGEMAIM
AMIGA
COMBATEDGE
FUND
GEMINI-E3
GTEM
IMAGE
IPAC
MERGE
MESSAGE
MiniCAMSGM
WIAGEM

Lessons Learned From Past
Inter-Model Comparison Studies;Things That Could Be Improved• Consider a broader range of uncertainties.
• Do more diagnostics.
• Better communication of results vis a vis what’sout there.
• Better communication of results to potential
users.
• More thought/work on forecasting accuracy.

Could Have Done Better #1
Reference & Optimistic Crude Oil Price
Projections From EMF 6Could Have Done Better #2
Average Wellhead Natural Gas Prices Across Models
Source: EMF 20

Could Have Done Better #3
Energy Demand Reductions Achievable for Similar
Carbon Prices Source: EMF 25

Current Trends in Inter-Model
Comparisons• With IT improvements, can do more.
• More people, modeling centers, global
collaborations: e.g., IAMC.
• Implementation modeling.
• “Forecasting”.
• More openness and better communication.

Suggestions for the Future of ModelComparisons, Diagnostics and Assessment• Better accounting for uncertainty• Better integration of assessment, model intercomparisons and validation• More implementation modeling and policy
relevant metrics• Better communication of all, especially theabove to decision makers• Tie high priority directions for future research
directly into assessments-VOI, etc.

Thank You