Overview of GCAM. November 29, 2011 PNNL-SA-84312

Transcription

1 Overview of GCAM November 29, 2011 PNNL-SA-84312

2 Outline! Brief introduction to Integrated Assessment Models! Overview GCAM! Detailed information on GCAM s! Economic assumptions,! Energy system,! Agriculture and land use system,! Climate system, and! Solution algorithm.

3 Integrated Assessment Models! Integrated Assessment (IA) Models! Combine information from numerous disciplines into one framework.! For climate problem, must be both global and long-term in scope.! Model development strategy considers tradeoffs between completeness and complexity, depending on goals.! IA Models Are Tools, useful to examine questions such as! possible futures with different assumptions for energy technologies, economic growth rates, etc. (thereby producing emission scenarios).! what are the important linkages: complementary, substitutes, feedbacks?! where are the lever points: technologies, resources, etc.?

4 GCAM has a long history! GCAM was one of four models chosen to create the representative concentration pathways for the IPCC s AR5! GCAM was one of three models used to create scenarios for the CCSP s scenario analysis.! GCAM has been a prominent tool for analysis in the Climate Change Technology Program.! GCAM has participated in virtually every major climate/energy/ economics assessment over the last 20 years:! Every EMF study on climate! Every IPCC assessment! GCAM has been used for strategic planning by energy and other private companies.! GCAM is now used by research institutions and governments internationally.

5 GCAM! Dynamic-recursive, technologically detailed integrated assessment model.! 14 geopolitical regions, 151 agriculture and land-use regions! Runs through 2095 in 5-year time steps 5

6 The GCAM Model Inputs Economy Supply/Demand s Emissions Climate Regional Resource Bases Regional Energy Conversion Technologies Energy Demand Technologies Energy Supply Coal, Gas, Oil Renewables Electricity Hydrogen Energy Demand Transportation Buildings Industry The Energy System Energy s Fossil fuel prices Electricity prices Hydrogen prices Energy System Emissions Climate Regional Labor Force Economy Economy Regional GDP Policy s Taxes Commercial Subsidies Bioenergy Regulation Climate Concentrations Radiative Forcing Global Mean Temperature Rise Sea Level Rise Regional Labor Productivity Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Land Use & Land Cover Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Agriculture & Land Use Agriculture & Land Related Emissions

7 Model Structure: The Economy! Population:! Exogenously specified! Current core model scenario assumes global population peaks in 2065 at roughly 9 billion people! GDP:! Exogenously specified assumptions about labor productivity growth! Current core model scenario assumes long-term labor productivity growth of approximately 1.5 percent per year in the developed world. Developing world growth is generally higher, with countries undergoing initially rapid growth which then slows toward the developed country levels over time.

8 The GCAM Model Inputs Economy Supply/Demand s Emissions Climate Regional Resource Bases Regional Energy Conversion Technologies Energy Demand Technologies Energy Supply Coal, Gas, Oil Renewables Electricity Hydrogen Energy Demand Transportation Buildings Industry Energy s Fossil fuel prices Electricity prices Hydrogen prices Energy System Energy System Emissions Regional Labor Force Regional GDP Policy s Taxes Subsidies Regulation Climate Concentrations Radiative Forcing Global Mean Temperature Rise Sea Level Rise Regional Labor Productivity Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Agriculture & Land Related Emissions Land Use & Land Cover

9 The Current Structure of the Energy System Resource Production Energy Transformation Final Energy Carriers End-Use Oil Production Liquids Refining Liquids Bioenergy Production Coal Production Bioenergy Conversion Bioenergy Coal Buildings Sector N. Gas Production Gas Processing Natural Gas Industrial Sector Uranium Nuclear Hydrogen Hydrogen Transport Sector Hydro Solar Wind Electric Power Generation Electricity Geothermal

10 Energy Resources in GCAM! Resources serve as inputs to conversion technologies to produce energy carriers such as electricity, liquid fuels, and hydrogen.! For example, several types of solar technologies CSP, central PV, rooftop PV draw from the solar resource to produce electricity.! Exhaustible Resources in GCAM! Coal! Natural Gas! Oil (conventional and unconventional)! Uranium! Renewable Resources in GCAM! Solar! Wind (onshore and offshore combined into one)! Geothermal! Bioenergy

11 The Current Structure of the Energy System Resource Production Energy Transformation Final Energy Carriers End-Use Oil Production Liquids Refining Liquids Bioenergy Production Coal Production Bioenergy Conversion Bioenergy Coal Buildings Sector N. Gas Production Gas Processing Natural Gas Industrial Sector Uranium Nuclear Hydrogen Hydrogen Transport Sector Hydro Solar Wind Electric Power Generation Electricity Geothermal

12 The Current Structure of the Energy System Purpose Grown Bioenergy: Production depends on land allocation and regional yield Land allocation depends on the profit rate of biomass AND all competing land uses Includes 1 st and 2 nd generation crops Crop & Forestry Residues: Potential production depends on crop production Fraction harvested depends on the price of bioenergy; higher prices lead to more production Some amount of residue must remain on the field for erosion control Purpose Grown Bioenergy Crop & Forestry Residues Bioenergy Production Municipal Solid Waste: Potential production depends population and income Fraction used for bioenergy depends on the price of bioenergy; higher prices lead to more production Municipal Solid Waste Note: We also model traditional bioenergy. However, it is not added to the bioenergy resource pool and is instead consumed directly by the buildings sector.

13 The Current Structure of the Energy System Resource Production Energy Transformation Final Energy Carriers End-Use Oil Production Liquids Refining Liquids Bioenergy Production Coal Production Bioenergy Conversion Bioenergy Coal Buildings Sector N. Gas Production Gas Processing Natural Gas Industrial Sector Uranium Nuclear Hydrogen Hydrogen Transport Sector Hydro Solar Wind Electric Power Generation Electricity Geothermal

14 Energy Conversion Sectors in GCAM! Final energy sectors in GCAM consume several fuels:! Electricity! Liquid Fuels! Coal! Bioenergy! Gaseous Fuels! Hydrogen! Corresponding to each of these is a conversion sector that takes as inputs various resources.! For example, liquid fuels are produced from bioenergy, conventional and unconventional oil, coal, and natural gas.! Conversion sectors can utilize a number of technologies, even for a single input fuel.! Bioenergy-to-liquids, for example, can be produced through several different technologies, with and without CCS.

15 The Current Structure of the Energy System Resource Production Energy Transformation Final Energy Carriers End-Use Oil Production Liquids Refining Liquids Bioenergy Production Coal Production Bioenergy Conversion Bioenergy Coal Buildings Sector N. Gas Production Gas Processing Natural Gas Industrial Sector Uranium Nuclear Hydrogen Hydrogen Transport Sector Hydro Solar Wind Electric Power Generation Electricity Geothermal

16 Electricity Generation Refined Liquids Bioenergy Coal Natural Gas Electric Power Generation Nuclear Hydro Solar Wind Geothermal

17 Coal Electric Technologies in GCAM! We model 4 different categories of coal power plants:! Existing coal plants! Pulverized coal plants! IGCC! IGCC with CO 2 Capture and Storage (CCS)! Each power plant has a different efficiency, non-energy cost, and emissions factor.! Which technology is deployed depends on the trade-offs between emissions and other costs. For example, IGCC with CCS will only deploy in a climate policy scenario.

18 Electricity in the United States! In the USA, we disaggregate the electricity load into four different segments: off peak, intermediate, sub peak, and on peak.! Note: We currently only disaggregate the load in the USA.

19 Genera2on in the United States! We disaggregate technologies into four different groups: base load, intermediate, sub peak, and peak! Base load operates at all hours of the year (not just off peak)! Note: We currently only disaggregate the load in the USA.

20 Storage technologies in the United States! Storage technologies consume baseload and supply the peak! IntermiEent tech solar and wind- (with no variable costs) could overbuild and store excess! Storage modeled as a NaS baeery due to energy density, 90% efficiency, and 15 year life@me! Other technologies may be added in the future Note: We currently only disaggregate the load in the USA.

21 Reference case results for the United States geo wind nuclear bio coal gas solar hydro bio+ccs coal+ccs gas+ccs Baseload geo wind nuclear bio coal gas liquids solar hydro bio+ccs coal+ccs gas+ccs liquids+ccs Intermediate EJ/yr EJ/yr EJ/yr liquids gas coal 1.5 bio nuclear wind geo 1.0 liquids+ccs gas+ccs coal+ccs bio+ccs hydro solar Subpeak EJ/yr liquids liquids+ccs gas gas+ccs coal coal+ccs bio bio+ccs nuclear hydro wind solar geo battery Peak Note: We currently only disaggregate the load in the USA

22 The Current Structure of the Energy System Resource Production Energy Transformation Final Energy Carriers End-Use Oil Production Liquids Refining Liquids Bioenergy Production Coal Production Bioenergy Conversion Bioenergy Coal Buildings Sector N. Gas Production Gas Processing Natural Gas Industrial Sector Uranium Nuclear Hydrogen Hydrogen Transport Sector Hydro Solar Wind Electric Power Generation Electricity Geothermal

23 Energy Demand Structure Liquids Bioenergy Buildings Sector Buildings Technologies Coal Natural Gas Industrial Sector Industrial Technologies We have detailed representations of transportation in all regions, and of buildings & industry in the USA. Hydrogen Transport Sector Transport Technologies Electricity

24 Energy Demand Structure: Transportation 24

25 Energy Demand Structure: Transportation Bus CNG Bus Diesel Bus Electric Bus H 2 Bus 25

26 The Current Structure of the Energy System Oil Production Liquids Refining Liquids Bioenergy Production Coal Production Bioenergy Conversion Bioenergy Coal Buildings Sector N. Gas Production Gas Processing Natural Gas Industrial Sector Uranium Nuclear Hydrogen Hydrogen Transport Sector Hydro Solar Wind Electric Power Generation Electricity Geothermal

27 The GCAM Energy System These systems can get very complicated very quickly. 27

28 GCAM Technology Competition A Probabilistic Approach Price Median Cost Technology 1 Median Cost Technology 2 Median Cost Technology 3! Economic competition among technologies takes place at many sectors and levels.! Assumes a distribution of realized costs due to heterogeneous conditions. `! share based on probability that a technology has the least cost for an application.! Avoids a winner take all result.! Logit specification. 28

29 GCAM Technology Competition s i = α c j i σ i α c j σ j Source: Clarke and Edmonds (1993), McFadden (1974) 100% Change in technology shares when tech 1 s cost increases by 20% 90% 80% 70% 60% 50% 40% tech 2 tech 1 30% 20% 10% 0% base year σ = 0 σ = - 1 σ = - 3 σ = - 6 σ = - 12 σ = - 24 σ = - 100

30 Vintaging! We assume that capital stock in certain sectors (for example, electric power generation and oil refining sectors) is long-lived.! This means that a power plant or refinery built in one model period *may* still be in operation many time periods later.! However, we do not assume that existing capital is always in operation. Once the variable cost exceeds the market price, we begin to shut down existing units. This often occurs when a carbon price is applied.

31 Trade in GCAM! We are NOT a trade model. Therefore, we do not model bilateral trade and instead model Heckscher-Ohlin trade.! For many products, we assume that trade is free and global. These products include coal, gas, oil, bioenergy, food, and fiber.! However, we can have differences in regional prices by including an adder to account for transportation costs, etc.! For other products, we assume that no interregional trade is allowed. These products include solar, wind, geothermal, meat, and dairy.! In this case, each region must produce enough to meet demand.

32 Bioenergy Trade in GCAM We model large scale bioenergy systems! Collection and Processing! Pelletizing important to increase the energy density of the fuel and facilitate transportation! Average cost to transport to local collection facility and pelletize of $2.18/GJ (2005$)! 85% of cost is in pelletizing! compare to $1.33/GJ for Coal (Edwards).! International transport cost of $0.31/GJ (2005$) added to all regions (assumes large ocean bulk carriers) (Van Vliet, 2009, consistent with Wolf 2006)

33 Emissions! GCAM tracks emissions for several gases and species! CO 2, CH 4, N 2 O, CF 4, C 2 F 6, SF 6, HFC125, HFC134, HFC245fa, SO 2, BC, OC, CO, VOCs, NOx, NH 3! We calculate CO 2 from fossil fuel & industrial uses, as well as from land-use change! Each gas is associated with a specific activity and changes throughout the coming century if:! The activity level changes! Increasing the activity increases emissions! Pollution controls increase! As incomes rise, we assume that regions will reduce pollutant emissions! A carbon price is applied! We use MAC curves to reduce the emissions of GHGs as the carbon price rises! Emissions are produced at a region level, but we can downscale them to grid cell level if necessary (e.g., RCPs)

34 HALF TIME

35 The GCAM Model Inputs Economy Supply/Demand s Emissions Climate Regional Resource Bases Regional Energy Conversion Technologies Energy Demand Technologies Energy Supply Coal, Gas, Oil Renewables Electricity Hydrogen Energy Demand Transportation Buildings Industry Energy s Fossil fuel prices Electricity prices Hydrogen prices Energy System Emissions Regional Labor Force Regional GDP Policy s Taxes Subsidies Regulation Climate Concentrations Radiative Forcing Global Mean Temperature Rise Sea Level Rise Regional Labor Productivity Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Land Use & Land Cover Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Agriculture & Land Related Emissions Agriculture & Land Use

36 Agriculture, Land-use and Energy in GCAM Energy Demand Transportation Buildings Industry Regional Labor Force Regional Labor Productivity Regional GDP Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Commercial Biomass Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Land Use & Land Cover Agriculture & Land Related Emissions

37 Agricultural Demand! GCAM currently models supply and demand for 12 crops, 6 animal categories, and bioenergy:! Crops: corn, rice, wheat, sugar, oil crops (e.g., soybeans), other grains (e.g., barley), fiber (e.g., cotton), fodder (e.g., hay, alfalfa), roots & tubers, fruits & vegetables! Animals: beef, dairy, pork, poultry, sheep/goat, other! Forest: roundwood! Bioenergy: switchgrass, miscanthus, jatropha, willow, eucalyptus, corn ethanol, sugar ethanol, biodiesel (from soybeans and other oil crops)! We account for both food and non-food demand, including animal feed.! Demand is modeled at the 14 region level.

38 Non-Food Demand! Non-food, non-feed demand:! Base year demand for non-food, non-feed uses FAO statistics! Future demand:! Per capita demand for crops, animals, and forestry products is currently fixed.! Thus, demand grows proportional to population, regardless of income or price.! Feed demand:! Base year demand for feed combines FAO statistics with data from the IMAGE model (PBL)! Future demand:! Depends on the growth in animal consumption, as well as the change in relative prices of feed options! Animal can either be grass-fed or grain-fed. The exact proportion of grass- vs. grain-fed depends on the price of pasture land as compared to the price of crops! Grain-fed animals can shift their diet as the relative prices of various crops change. However, the elasticity is relatively low to prevent dramatic shifts that may comprise an unsustainable diet.

39 Food Demand! Base year demand for food uses FAO statistics! Future demand in the baseline is calibrated to match FAO projections of crop and meat demand through After 2050, we assume that per capita demand is constant.! Meat demand in GCAM is price responsive. As the price of meat increases, meat demand will decline.! The current price elasticity is very low (~0.25). This is consistent with USDA data for the USA and Australia. Developing countries typically have more elastic demand, but our default assumption is very conservative.! Crop demand is not price responsive.

40 Food Demand '#!!" Total Food Consumption ($"# % of Calories from Meat '!!!" (!"#!"#$%&'()*'%)*'%($+)*'%),"-) &#!!" &!!!" %#!!" %!!!" $#!!" $!!!" #!!" +,-"./0/1/" "7869:3" ;/:/0" -8456/<=/>?@" A96B36",9C=35"+0=90".D=0/" E=11<3"7/45" -F6=G/" H/I0"-B36=G/",985D3/45"-4=/" 7/45360"7869:3" J963/" K01=/"!" %!!#" %!%!" %!&#" %!#!" %!(#" %!)!" %!*#" '$"# '!"# &$"# &!"# %$"# %!"# $"#!"# &!!$# &!&!# &!'$# &!$!# &!)$# &!*!# &!+$#

41 Agriculture, Land-use and Energy in GCAM Energy Demand Transportation Buildings Industry Regional Labor Force Regional Labor Productivity Regional GDP Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Commercial Biomass Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Land Use & Land Cover Agriculture & Land Related Emissions

42 Agricultural Technologies! For each crop and region, we have started with a single production technology.! The yield for this technology is calculated from GTAP/FAO statistics, by dividing total production in a region by land area.! GCAM results are production per year, not per harvest. Thus, we use total physical crop land area to calculate yield and not harvested area. If a region actually harvests more than once a year, their economic yield (used by GCAM) will be larger than the actual physical yield.! We exogenously specify technical change for agricultural technologies.! We use FAO projections through FAO provides this information for each crop and country. We need it per crop and AEZ. Currently, we are using the average across crops and countries within each of the 14 geopolitical regions of GCAM.! After 2050, we assume that yields will improve by 0.25% per year for all crops and regions.

43 Agriculture Productivity Growth Average $"!# regional yield in the output will differ from these values ("'# as crop production shifts ("&# across subregions.!"#$%&'())*+,-& ("%# ("$# ("!#!"'#!"&#!"%#!"$#,-.# /01020# #897:;4# B:7C47#-:D>46#,1>:1# /E>10# F>22=4#8056#.G7>H0# I0J1#.C47>H0# -:96E4056#.5>0# #897:;4# K:740# L12>0#!"!# $!!)# $!$!# $!*)# $!)!# $!&)# $!'!# $!+)#

44 Agriculture, Land-use and Energy in GCAM Energy Demand Transportation Buildings Industry Regional Labor Force Regional Labor Productivity Regional GDP Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Commercial Biomass Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Land Use & Land Cover Agriculture & Land Related Emissions

45 Basic Assumptions! The world is divided into 151 regions

46 GCAM Regions

47 GTAP-AEZs Monfreda et al. (2009)

48 151 Different AgLU Supply Regions

49 Basic Assumptions! The world is divided into 151 regions! Farmers allocate land across a variety of uses in order to maximize profit! There is a distribution of profits for each land type across each of the 151 regions! The actual share of land allocated to a particular use is the probability in which that land type has the highest profit! The variation in profit rates is due to variation in the cost of production! As the area devoted to a particular land use expands, cost increases! Yield is fixed within each region for each crop management practice

50 USA Wheat Yield While yield is fixed within each subregion, there is a distribution of yields across each of the 14 GCAM regions.

51 GCAM Land Competition

52 GCAM Land Competition s i = (! i " i )! (" j # j )!! j Source: Clarke and Edmonds (1993), McFadden (1974) Change in land shares when land type 1 s profit increases by 20% -./0#1234#$# -./0#1234#%# $!!"#,!"# +!"# *!"# )!"# (!"# '!"# &!"# %!"# $!"#!"#!"#$%&$"'% (%)%*% (%)%*+,% (%)%*+-% (%)%,% (%)%.% (%)%/% (%)%0% (%)%-% (%)%1% (%)%2% (%)%3% (%)%4% (%)%,*% (%)%-*% (%)%,**%

53 GCAM Land Competition!"#$%&''()$*(+,-./0)$ #!" +" *" )" (" '" &" %",-./01234".3",56.-"789:3",-./01234".3"$!;"789:3"<=18>./>",-./01234".3"#!!;"789:3"2=18>./>" $" #"!"!" $" &" (" *" #!" 123/0$*4'2#5#0,$ Supply elasticities are not constant with the logit formulation. Elasticities are higher when profits are similar across land types.

54 GCAM Nesting Structure

55 Agriculture, Land-use and Energy in GCAM Energy Demand Transportation Buildings Industry Regional Labor Force Regional Labor Productivity Regional GDP Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Commercial Biomass Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Land Use & Land Cover Agriculture & Land Related Emissions

56 Agricultural Supply! Yield is exogenously calculated.! Base year derived from GTAP/FAO production and land area.! Yields increase over time based on exogenously specified technical change.! Land area is endogenously calculated.! Each land types share of area in its region is the probability its profit is the highest in that region.! Supply = land * yield

57 Agriculture, Land-use and Energy in GCAM Energy Demand Transportation Buildings Industry Regional Labor Force Regional Labor Productivity Regional GDP Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Commercial Biomass Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Land Use & Land Cover Agriculture & Land Related Emissions

58 Calculating Vegetation CO 2 Emissions! First, we determine the total change in carbon stock for each land type and region.! Δ C Stock = [Land Area (t)]*[c density (t)] - [Land Area (t-1)]*[c density (t-1)]! Then, we allocate that change across time.! If change in land area decreases the carbon stock (e.g., deforestation), then all carbon is released into the atmosphere instantaneously.! If the change in land area increases the carbon stock (e.g., afforestation), then carbon accumulates slowly over time, depending on an exogenously specified mature age.! The mature age varies by land type and region.

59 Forest Carbon Uptake 100% 75% 50% 25% 0%

60 Calculating Soil CO 2 Emissions! First, we determine the total change in carbon stock for each land type and region.! Δ C Stock = [Land Area (t)]*[c density (t)] - [Land Area (t-1)]*[c density (t-1)]! Then, we allocate that change across time.! Whether carbon stock increases or decreases, we assume that the change is allocated evenly over a read in number of years.! The number of years varies by region, but not by land type.! In general, colder regions have longer soil carbon time scales.

61 Non-CO 2 Emissions! Base year emissions are calibrated to match the RCP data set. We use this data to calculate emissions factors (emissions per unit of activity) for all crops and animals, as well as some land sources (savannah burning, deforestation, forest fires)! Future emissions:! Increase if drivers increase! Decrease if abatement options are available and a carbon price is imposed. We use the EPA MAC curves in this case.

62 Non-CO 2 Emissions Source Gas MACs Crop Production CH 4, N 2 O Yes Ag Waste Burning VOCs, NO x, NH 3 CH 4, N 2 O, BC, OC, SO 2, NO x, VOCs, NH 3 No No Bioenergy N 2 O Yes Meat CH 4, N 2 O Yes Savannah burning Forest fires/deforestation NH 3 CH 4, N 2 O, BC, OC, SO 2, NO x, VOCs, NH 3 CH 4, N 2 O, BC, OC, SO 2, NO x, VOCs, NH 3 No No No

63 Agriculture, Land-use and Energy in GCAM Energy Demand Transportation Buildings Industry Regional Labor Force Regional Labor Productivity Regional GDP Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Commercial Biomass Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Land Use & Land Cover Policies Taxes Subsidies Regulation Agriculture & Land Related Emissions

64 Land Use Policies! Valuing carbon in land:! In this policy, we assume that land use change emissions are taxed at the same rate as fossil fuel and industrial emissions.! We implement this by subsidizing all land owners for holding carbon stocks.! This is the default assumption in GCAM.! REDD:! In this policy, we set aside some land from economic competition. This land cannot be converted to crops, pasture, or any other land type.! Carbon Parks:! For this policy, we base the profit rate of a type of land on its carbon content.! Bioenergy constraints (upper or lower):! We can also constraint biomass to a particular level. This is implemented in GCAM as a tax or subsidy on bioenergy consumption. The tax/subsidy is adjusted until the constraint is met.

65 The GCAM Model Inputs Economy Supply/Demand s Emissions Climate Regional Resource Bases Regional Energy Conversion Technologies Energy Demand Technologies Energy Supply Coal, Gas, Oil Renewables Electricity Hydrogen Energy Demand Transportation Buildings Industry Energy s Fossil fuel prices Electricity prices Hydrogen prices Energy System Emissions Climate Regional Labor Force Regional GDP Policy s Taxes Subsidies Regulation Climate Concentrations Radiative Forcing Global Mean Temperature Rise Sea Level Rise Regional Labor Productivity Technologies Regional Land Characteristics Agricultural Demand Crops Livestock Forest Products Agricultural Supply Crops Livestock Forest Products Bioenergy Agricultural s Crops prices Livestock prices Forest Product prices Bioenergy prices Agriculture & Land Related Emissions Land Use & Land Cover

66 GCAM uses MAGICC as a climate model! GCAM uses MAGICC 5.3 to compute climate related outputs.! We have translated the original Fortran code into C++.! We adjust the computation of radiative forcing from black and organic carbon.! Inputs:! GCAM passes emissions by timestep into MAGICC.! Fossil fuel & Industrial CO 2, Land-Use Change CO 2, CH 4, N 2 O, SF 6, C 2 F 6, CF 4, HFC125, HFC227ea, HFC245fa, SO 2 in 3 aggregate regions, CO, NO x, NMVOCs, BC, OC! Outputs:! MAGICC computes concentrations and radiative forcing of all substances.! It also computes global mean temperature rise (both observed and equilibrium) and sea level rise.

67 GCAM Solution Process We use a combination of bracketing/bisection Initially, this vectorand is Newton-Raphson with an educated guess. backtracking to update prices. Step 1: Choose a vector of prices. Step 2: Run GCAM. If no Step 3: Test whether supply = demand for all markets. If yes We re done! = 5?

68 QUESTIONS?