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

Fuel

Energy carriers. Abbreviation: f.

Scenario database

Table: FUEL

Name	Type	Description
`val`	text	Unique identifier for fuel
`desc`	text	Description of fuel
`timesliced`	text	Determines whether NEMO simulates production, consumption, and trade of fuel in time slices (`1`) or at annual level only (`0`); default value = `1`

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

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`)

Region

Geographic regions. Abbreviation: r.

Scenario database

Table: REGION

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

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

Tip

To assign regions to region groups, use the RRGroup parameter.

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)

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

Technology group

Groups of technologies. Each technology can belong to multiple groups. Abbreviation: tg.

Scenario database

Table: TECHNOLOGYGROUP

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

Tip

To assign technologies to technology groups, use the TTGroup parameter.

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

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)

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)

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`)

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