Snapshot of - WITNESS

Archive of WITNESS, version: 2.0

Reference card - WITNESS

The reference card is a clearly defined description of model features. The numerous options have been organized into a limited amount of default and model specific (non default) options. In addition some features are described by a short clarifying text.

Legend:

• not implemented
• implemented
• implemented (not default option)

About

Name and version

WITNESS 2.0

Model link

https://www.witness4climate.org/world-environmental-impact-and-economics-scenarios/

Institution

Open-Source for Climate (OS-C), N/A, https://os-climate.org/transition-analysis/., Linux Foundation (LF), N/A, https://www.linuxfoundation.org/.

Documentation

WITNESS documentation consists of a referencecard and detailed model documentation

Process state

in preparation

Model scope and methods

Model documentation: Model scope and methods - WITNESS

Model type

• Integrated assessment model
• Energy system model
• CGE
• CBA-integrated assessment model

Geographical scope

• Global
• Regional

Objective

IAM framework enabling simulation, multi-domain analysis or optimization involving all or part of Economy, Energy, Resources, Climate, Population, Public policies. A typical usage is to optimize over years economy investment across available energy production technologies to maximize produced energy while minimizing emissions within resources constraints (or globally to maximize welfare under constraints).

Solution concept

• Partial equilibrium (price elastic demand)
• Partial equilibrium (fixed demand)
• General equilibrium (closed economy)
• Systems dynamics based approach

Note: Complex system of systems simulation approach with all systems fully coupled

Solution horizon

• Recursive dynamic (myopic)
• Intertemporal optimization (foresight)

Solution method

• Simulation
• Optimization
• Simulation-based optimization

Note: Advanced applied mathematics for multi-disciplinary analysis and optimization of complex system of systems applied to IAM scope

Temporal dimension

Base year:2020, time steps:yearly, horizon: user defined (typically now to 2100 )

Note: yearly timestep for convenient alignment with datasets, but numerically any timestep could be choosen

Spatial dimension

Number of regions:Global

Note: Regionalization in progress (high level regionalization with 5-10 macro-regions expected for end'23, smart spatial multi-scaling by end'24)

Time discounting type

• Discount rate exogenous
• Discount rate endogenous

Policies

• Emission tax
• Emission pricing
• Cap and trade
• Fuel taxes
• Fuel subsidies
• Feed-in-tariff
• Portfolio standard
• Capacity targets
• Emission standards
• Energy efficiency standards
• Agricultural producer subsidies
• Agricultural consumer subsidies
• Land protection
• Pricing carbon stocks
• Renewable energy subsidies

Socio-economic drivers

Model documentation: Socio-economic drivers - WITNESS

Population

• Yes (exogenous)
• Yes (endogenous)

Population age structure

• Yes (exogenous)
• Yes (endogenous)

Education level

• Yes (exogenous)
• Yes (endogenous)

Urbanization rate

• Yes (exogenous)
• Yes (endogenous)

GDP

• Yes (exogenous)
• Yes (endogenous)

Income distribution

• Yes (exogenous)
• Yes (endogenous)

Employment rate

• Yes (exogenous)
• Yes (endogenous)

Labor productivity

• Yes (exogenous)
• Yes (endogenous)

Total factor productivity

• Yes (exogenous)
• Yes (endogenous)

Autonomous energy efficiency improvements

• Yes (exogenous)
• Yes (endogenous)

Other socio economic driver

• Behavioural change

Macro-economy

Model documentation: Macro-economy - WITNESS

Economic sector

Industry

• Yes (physical)
• Yes (economic)
• Yes (physical & economic)

Energy

• Yes (physical)
• Yes (economic)
• Yes (physical & economic)

Transportation

• Yes (physical)
• Yes (economic)
• Yes (physical & economic)

Residential and commercial

• Yes (physical)
• Yes (economic)
• Yes (physical & economic)

Agriculture

• Yes (physical)
• Yes (economic)
• Yes (physical & economic)

Forestry

• Yes (physical)
• Yes (economic)
• Yes (physical & economic)

Macro-economy

Trade

• Coal
• Oil
• Gas
• Uranium
• Electricity
• Bioenergy crops
• Food crops
• Capital
• Emissions permits
• Non-energy goods

Cost measures

• GDP loss
• Welfare loss
• Consumption loss
• Area under MAC
• Energy system cost mark-up

Categorization by group

• Income
• Urban - rural
• Technology adoption
• Age
• Gender
• Education level
• Household size

Institutional and political factors

• Early retirement of capital allowed
• Interest rates differentiated by country/region
• Regional risk factors included
• Technology costs differentiated by country/region
• Technological change differentiated by country/region
• Behavioural change differentiated by country/region
• Constraints on cross country financial transfers

Resource use

Coal

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Conventional Oil

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Unconventional Oil

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Conventional Gas

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Unconventional Gas

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Uranium

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Bioenergy

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Water

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Raw Materials

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Land

• Yes (fixed)
• Yes (supply curve)
• Yes (process model)

Other resource use

• Copper

Technological change

Energy conversion technologies

• No technological change
• Exogenous technological change
• Endogenous technological change

Energy End-use

• No technological change
• Exogenous technological change
• Endogenous technological change

Material Use

• No technological change
• Exogenous technological change
• Endogenous technological change

Agriculture (tc)

• No technological change
• Exogenous technological change
• Endogenous technological change

Energy

Model documentation: Energy - WITNESS

Energy technology substitution

Energy technology choice

• No discrete technology choices
• Logit choice model
• Production function
• Linear choice (lowest cost)
• Lowest cost with adjustment penalties

Energy technology substitutability

• Mostly high substitutability
• Mostly low substitutability
• Mixed high and low substitutability
• Discrete technology choices with mostly high substitutability in some sectors and mostly low substitutability in other sectors

Energy technology deployment

• Expansion and decline constraints
• System integration constraints

Energy

Electricity technologies

• Coal w/o CCS
• Coal w/ CCS
• Gas w/o CCS
• Gas w/ CCS
• Oil w/o CCS
• Oil w/ CCS
• Bioenergy w/o CCS
• Bioenergy w/ CCS
• Geothermal power
• Nuclear power
• Solar power
• Solar power-central PV
• Solar power-distributed PV
• Solar power-CSP
• Wind power
• Wind power-onshore
• Wind power-offshore
• Hydroelectric power
• Ocean power

Hydrogen production

• Coal to hydrogen w/o CCS
• Coal to hydrogen w/ CCS
• Natural gas to hydrogen w/o CCS
• Natural gas to hydrogen w/ CCS
• Oil to hydrogen w/o CCS
• Oil to hydrogen w/ CCS
• Biomass to hydrogen w/o CCS
• Biomass to hydrogen w/ CCS
• Nuclear thermochemical hydrogen
• Solar thermochemical hydrogen
• Electrolysis
• Plasma cracking
• Electrolysis SOEC
• Electrolysis PEM
• Eletrolysis AWE
• WaterGasShift

Refined liquids

• Coal to liquids w/o CCS
• Coal to liquids w/ CCS
• Gas to liquids w/o CCS
• Gas to liquids w/ CCS
• Bioliquids w/o CCS
• Bioliquids w/ CCS
• Oil refining
• FisherTropsch
• HefaDecarboxydation
• HefaDeoxygenation
• Transesterification

Refined gases

• Coal to gas w/o CCS
• Coal to gas w/ CCS
• Oil to gas w/o CCS
• Oil to gas w/ CCS
• Biomass to gas w/o CCS
• Biomass to gas w/ CCS
• AnaerobicDigestion
• SteamMethaneReforming
• Pyrolisis
• AutothermalReforming
• CoElectrolysis

Heat generation

• Coal heat
• Natural gas heat
• Oil heat
• Biomass heat
• Geothermal heat
• Solarthermal heat
• CHP (coupled heat and power)
• FossilGas
• Pelletizing
• ManagedWood
• UnmanagedWood
• CropEnergy

Grid Infra Structure

Electricity

• Yes (aggregate)
• Yes (spatially explicit)

Gas

• Yes (aggregate)
• Yes (spatially explicit)

Heat

• Yes (aggregate)
• Yes (spatially explicit)

CO2

• Yes (aggregate)
• Yes (spatially explicit)

Hydrogen

• Yes (aggregate)
• Yes (spatially explicit)

Energy end-use technologies

Passenger transportation

• Passenger trains
• Buses
• Light Duty Vehicles (LDVs)
• Electric LDVs
• Hydrogen LDVs
• Hybrid LDVs
• Gasoline LDVs
• Diesel LDVs
• Passenger aircrafts

Freight transportation

• Freight trains
• Heavy duty vehicles
• Freight aircrafts
• Freight ships

Industry

• Steel production
• Aluminium production
• Cement production
• Petrochemical production
• Paper production
• Plastics production
• Pulp production

Residential and commercial

• Space heating
• Space cooling
• Cooking
• Refrigeration
• Washing
• Lighting

Land-use

Model documentation: Land-use - WITNESS

Land cover

• Cropland
• Cropland irrigated
• Cropland food crops
• Cropland feed crops
• Cropland energy crops
• Forest
• Managed forest
• Natural forest
• Pasture
• Shrubland
• Built-up area
• SolarThermal
• SolarPV

Agriculture and forestry demands

• Agriculture food
• Agriculture food crops
• Agriculture food livestock
• Agriculture feed
• Agriculture feed crops
• Agriculture feed livestock
• Agriculture non-food
• Agriculture non-food crops
• Agriculture non-food livestock
• Agriculture bioenergy
• Agriculture residues
• Forest industrial roundwood
• Forest fuelwood
• Forest residues

Agricultural commodities

• Wheat
• Rice
• Other coarse grains
• Oilseeds
• Sugar crops
• Ruminant meat
• Non-ruminant meat and eggs
• Dairy products
• Eggs
• Fruits & vegetables
• White meat
• Potatoes

Emission, climate and impacts

Model documentation: Emissions - WITNESS, Climate - WITNESS, Non-climate sustainability dimension - WITNESS

Greenhouse gases

• CO2 fossil fuels
• CO2 cement
• CO2 land use
• CH4 energy
• CH4 land use
• CH4 other
• N2O energy
• N2O land use
• N2O other
• CFCs
• HFCs
• SF6
• PFCs

Pollutants

• CO energy
• CO land use
• CO other
• NOx energy
• NOx land use
• NOx other
• VOC energy
• VOC land use
• VOC other
• SO2 energy
• SO2 land use
• SO2 other
• BC energy
• BC land use
• BC other
• OC energy
• OC land use
• OC other
• NH3 energy
• NH3 land use
• NH3 other

Climate indicators

• Concentration: CO2
• Concentration: CH4
• Concentration: N2O
• Concentration: Kyoto gases
• Radiative forcing: CO2
• Radiative forcing: CH4
• Radiative forcing: N2O
• Radiative forcing: F-gases
• Radiative forcing: Kyoto gases
• Radiative forcing: aerosols
• Radiative forcing: land albedo
• Radiative forcing: AN3A
• Radiative forcing: total
• Temperature change
• Sea level rise
• Ocean acidification

Carbon dioxide removal

• Bioenergy with CCS
• Reforestation
• Afforestation
• Soil carbon enhancement
• Direct air capture
• Enhanced weathering
• CalciumLooping
• ChilledAmmoniac
• CO2Membranes
• MonoEthanolAmine
• Piperazine
• PressureSwingAdsorbtion
• AmineScrubbing
• CalciumPotassiumScrubbing
• BiomassBryingFossilization
• DeepOceanInjection
• DeepSalineFormation
• DepletedOilGas
• EnhancedOilRecovery
• GeologicMineralization
• PureCarbonSolidStorage

Climate change impacts

• Agriculture
• Energy supply
• Energy demand
• Economic output
• Built capital
• Inequality
• Utility/Welfare

Co-Linkages

• Energy security: Fossil fuel imports & exports (region)
• Energy access: Household energy consumption
• Air pollution & health: Source-based aerosol emissions
• Air pollution & health: Health impacts of air Pollution
• Food access
• Water availability
• Biodiversity

1) Model scope and methods - WITNESS

WITNESS stands for World environmental ImpacT aNd Economics ScenarioS.

It is a global Integrated Assessment Model (IAM) framework, covering the world globally (regionalization and sectorization are in progress to be fully completed by end'24). The framework covers MacroEconomics, Energy, Materials, Natural resources, Environment, Population and Public Policies. The methodological approach to implementing WITNESS is to apply complex system of systems simulation techniques to IAM modelling. The underlying simulation platform used is called SoSTrades (System of Systems Trades).

At the top level, a system of systems approach define high level systems and their interactions (which you can roughly see in the picture above). From an implementation point of view, they will define namespaces within which sub-system models will interact and exchange. An ontology is also defined to formalize all modules and parameter's names. In the main namespace, all interfaces exposed by each of the main systems are automatically coupled using the ontology semantic and multidisciplinary analysis (MDA) coupling templates.

Going down recursively refining each system is similar, you will define sub-namespaces for each sub-system you identify to further refine it if needed, and you will define your current systems interfaces to let them be automatically be coupled through the ontology in your current namespace.

This methodology allow for easy refinement of models as the models interconnexions are prescriptive (expose interfaces in specific namespaces) but not descriptive (connections handling is automated an holistic within namespace). You can also decide to replace in some area the driver running multidisciplinary analysis (MDA), by a controller running multi-disciplinary optimization (MDO) of you want to orient the result vs an objective or want to respect specific constraints. For example in the basic WITNESS framework, an MDO controller is optimizing ventilation of available investment from Macro-economy to various Energy production techniques in Energy system, in order to maximize energy production while minimizing emissions under resources and materials contraints.

The SoSTrades simulation platform is a cooperative platform with a multi-user web front-end and cloud backend (Docker/Kubernetes). The model themselves are written in Python language and wrapped in an SoSTrades discipline that integrate model code, documentation, interfaces... Models not written in Python or requesting specific setup (libraries, licenses, computing infrastructure...) can be integrated through a REST API (or any available python mechanism). Coupling of the models is performed using an extended / improved version of GEMSEO library, that is providing various applied mathematics standard solvers implementation. The platform facilitated usage of full adjoint based optimization by consistently managing gradients, that makes optimization cost almost independent of the number of parameters used. Those gradient also enable sensitivity analyses.

The platform itself can be used through a REST API to setup / run / analyse a scenario, and generate a synthesis HTML widget that can be embedded in some external dashboard.

_____________________

WITNESS and SoSTrades are part of Transition analysis project of the Open Source for Climate initiative from the Linux Foundation, and their development is supported by Capgemini.

More details can be found on witness4climate.org website.

1.3) Temporal dimension - WITNESS

WITNESS iterations are typically 1 year iterations.

The underlying mechanism could accommodate with smaller or bigger time steps, but for models calibration purposes it was convenient to get 1 year steps as many data are available at a 1 year interval.

3) Macro-economy - WITNESS

More detailed documentation on WITNESS macro-economy model can be found in the module embedded documentation,

accessible within the tool or directly consulting the module documentation in gitlab

4) Energy - WITNESS

The energy mix discipline acts at the top of energy models, with the goal to aggregate the information arriving from each energy, calculate the net production and the CO2 emissions per kwh of energy.

These information are then send back to technologies to compute technology production and prices.

In the basic WITNESS framework, investments in energy are optimally split among available production technologies to maximize energy production while minimizing CO2 emission under constraints

5) Land-use - WITNESS

More detailed documentation on WITNESS land use model can be found in the module embedded documentation,

accessible within the tool or directly consulting the documentation directly in the gitlab Land use model

5.1) Agriculture - WITNESS

More detailed documentation on WITNESS land use model can be found in the module embedded documentation,

accessible within the tool or directly consulting the documentation directly in gitlab

for Agriculture module

5.2) Forestry - WITNESS

More detailed documentation on WITNESS land use model can be found in the module embedded documentation,

accessible within the tool or directly consulting the documentation directly in the gitlab

Forests model