Dimensions

Input parameters and calculated variables in NEMO are segmented (subscripted) by certain key components of the energy system. These model dimensions describe geographical, technological, temporal, and other elements of the system. You define dimensions for each NEMO scenario, and they can vary between scenarios for a given energy system. Dimensions are specified in tables in a NEMO scenario database as outlined below. Each dimension has an abbreviation that's used when referring to it in NEMO's code and scenario databases.

Emission

Emissions or other externalities in the energy system. You can associate costs with emissions, and the quantity of emissions produced can be constrained (see Parameters). Abbreviation: e.

Scenario database

Table: EMISSION

Name	Type	Description
`val`	text	Unique identifier for emission
`desc`	text	Description of emission

Julia code

Set of emissions: semission (an Array of EMISSION.val)
Subscript for emissions in other variables: e

Fuel

Energy carriers. Abbreviation: f.

Scenario database

Table: FUEL

Name	Type	Description
`val`	text	Unique identifier for fuel
`desc`	text	Description of fuel

Julia code

Set of fuels: sfuel (an Array of FUEL.val)
Subscript for fuels in other variables: f

Mode of operation

Different ways in which technologies can function. Typically, one mode is defined for energy generation or production; if a scenario models energy storage, another is defined for charging storage. Abbreviation: m.

Scenario database

Table: MODE_OF_OPERATION

Name	Type	Description
`val`	text	Unique identifier for mode
`desc`	text	Description of mode

Julia code

Set of modes: smode_of_operation (an Array of MODE_OF_OPERATION.val)
Subscript for modes in other variables: m

Node

Locations in a transmission (or transmission and distribution) network. Networks are defined with nodes and transmission lines or segments, and nodal modeling of energy demand and supply can be enabled for individual fuels. Abbreviation: n.

Scenario database

Table: NODE

Name	Type	Description
`val`	text	Unique identifier for node
`desc`	text	Description of node
`r`	text	Region in which node is located (`REGION.val`)

Julia code

Set of nodes: snode (an Array of NODE.val)
Subscript for nodes in other variables: n

Region

Geographic regions. Abbreviation: r.

Scenario database

Table: REGION

Name	Type	Description
`val`	text	Unique identifier for region
`desc`	text	Description of region

Julia code

Set of regions: sregion (an Array of REGION.val)
Subscript for regions in other variables: r

Region group

Groups of geographic regions. Each region can belong to multiple groups. Abbreviation: rg.

Scenario database

Table: REGIONGROUP

Name	Type	Description
`val`	text	Unique identifier for region group
`desc`	text	Description of region group

Julia code

Subscript for region groups in variables: rg

Storage

Energy storage options or facilities. Abbreviation: s.

Scenario database

Table: STORAGE

Name	Type	Description
`val`	text	Unique identifier for storage
`desc`	text	Description of storage
`netzeroyear`	integer	Indicates that storage can have no net charging or discharging over a year (`1` = enabled)
`netzerotg1`	integer	Indicates that storage can have no net charging or discharging over a time slice group 1 (`1` = enabled)
`netzerotg2`	integer	Indicates that storage can have no net charging or discharging over a time slice group 2 (`1` = enabled)

Julia code

Set of storage: sstorage (an Array of STORAGE.val)
Subscript for storage in other variables: s

Technology

Energy-consuming or producing devices or equipment. Abbreviation: t.

Scenario database

Table: TECHNOLOGY

Name	Type	Description
`val`	text	Unique identifier for technology
`desc`	text	Description of technology

Julia code

Set of technologies: stechnology (an Array of TECHNOLOGY.val)
Subscript for technologies in other variables: t

Time slice

Sub-annual periods used to model energy demand and supply in selected cases. The width of each time slice (as a fraction of the year) is defined with the parameter YearSplit. Abbreviation: l.

Scenario database

Table: TIMESLICE

Name	Type	Description
`val`	text	Unique identifier for time slice
`desc`	text	Description of time slice

Julia code

Set of time slices: stimeslice (an Array of TIMESLICE.val)
Subscript for technologies in other variables: l

Time slice group 1

Groupings of time slices within a year. Abbreviation: tg1.

Scenario database

Table: TSGROUP1

Name	Type	Description
`name`	text	Unique identifier for group
`desc`	text	Description of group
`order`	integer	Order of group within a year (should be `1` for first group, incremented by 1 for subsequent groups)
`multiplier`	real	Multiplier used in storage calculations (see Time slicing)

Julia code

Set of groups: stsgroup1 (an Array of TSGROUP1.name)
Subscript for groups in other variables: tg1

Time slice group 2

Groupings of time slices within a time slice group 1. Abbreviation: tg2.

Scenario database

Table: TSGROUP2

Name	Type	Description
`name`	text	Unique identifier for group
`desc`	text	Description of group
`order`	integer	Order of group within a time slice group 1 (should be `1` for first group, incremented by 1 for subsequent groups)
`multiplier`	real	Multiplier used in storage calculations (see Time slicing)

Julia code

Set of groups: stsgroup2 (an Array of TSGROUP2.name)
Subscript for groups in other variables: tg2

Transmission line

Connections between nodes in a transmission (or transmission and distribution) network - e.g., electrical lines or pipes in a natural gas network. Transmission lines allow energy to flow from one node to another. Abbreviation: tr.

Scenario database

Table: TransmissionLine

Name	Type	Description
`id`	text	Unique identifier for line
`n1`	text	First node connected to line (`NODE.val`)
`n2`	text	Second node connected to line (`NODE.val`)
`f`	text	Fuel transported over line (`FUEL.val`)
`maxflow`	real	Maximum flow supported by line (MW)
`reactance`	real	Line's reactance (per unit assuming a 1 MVA power base, only relevant for electrical lines when using direct current optimized power flow modeling; see `TransmissionModelingEnabled`)
`yconstruction`	integer	Exogenously specified construction year for line (leave null if NEMO should endogenously determine whether to build line [i.e., for candidate lines])
`capitalcost`	real	Line's capital cost (scenario's cost unit)
`fixedcost`	real	Line's fixed annual operation and maintenance cost (scenario's cost unit)
`variablecost`	real	Line's variable operation and maintenance (scenario's cost unit / energy unit)
`operationallife`	integer	Line's operational lifetime (years, used to retire both exogenously and endogenously built lines)
`efficiency`	real	Efficiency of transmission over line (%, only used for pipeline flow modeling; see `TransmissionModelingEnabled`)
`interestrate`	real	Interest rate NEMO should use to calculate financing costs if building line endogenously (0 to 1; see `vfinancecosttransmission`)

Julia code

Set of lines: stransmission (an Array of TransmissionLine.id)
Subscript for lines in other variables: tr

Note

NEMO includes binary decision variables in a scenario's optimization problem if you a) model a transmission line with a non-zero variable cost; or b) model a line with an efficiency less than 1 using transmission modeling type 3. This can increase solver run-time.

Year

Years covered by scenario. Years must be integral. Abbreviation: y.

Scenario database

Table: YEAR

Name	Type	Description
`val`	text	Unique identifier for year
`desc`	text	Description of year

Julia code

Set of years: syear (an Array of YEAR.val in numeric order)
Subscript for years in other variables: y