Transmission, node, and trade parameters
These parameters support nodal transmission modeling and trade between regions. They include controls for enabling transmission modeling, transmission line performance and investment limits, the distribution of demand and capacity across nodes, and trade routes.
Maximum annual transmission between nodes
For the indicated fuel and year, maximum energy that can be received at the second node (n2) via transmission from the first node (n1). Energy received is net of any transmission losses.
Scenario database
Table: MaxAnnualTransmissionNodes
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
n1 | text | Node sending energy |
n2 | text | Node receiving energy |
f | text | Fuel |
y | text | Year |
val | real | Energy (energy unit for regions containing n1 and n2) |
Minimum annual transmission between nodes
For the indicated fuel and year, minimum energy that must be received at the second node (n2) via transmission from the first node (n1). Energy received is net of any transmission losses.
Scenario database
Table: MinAnnualTransmissionNodes
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
n1 | text | Node sending energy |
n2 | text | Node receiving energy |
f | text | Fuel |
y | text | Year |
val | real | Energy (energy unit for regions containing n1 and n2) |
Nodal distribution demand
For the specified node and the region containing it, fraction of the region's exogenously defined demands for the specified fuel that is assigned to the node. Exogenously defined demands include specified annual demand and accumulated annual demand.
If in a given year transmission modeling is enabled for a fuel and region (see TransmissionModelingEnabled), and the fuel has exogenous demands in the region, the sum of NodalDistributionDemand across the nodes in the region should be 1.
Scenario database
Table: NodalDistributionDemand
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
n | text | Node |
f | text | Fuel |
y | text | Year |
val | real | Fraction (0 to 1) |
Nodal distribution storage capacity
For the specified node and the region containing it, fraction of the specified storage's capacity in the region that is assigned to the node.
Scenario database
Table: NodalDistributionStorageCapacity
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
n | text | Node |
s | text | storage |
y | text | Year |
val | real | Fraction (0 to 1) |
To enable nodal modeling for a storage, you must define NodalDistributionStorageCapacity and activate transmission modeling for the storage's input and output fuels. Use the TransmissionModelingEnabled parameter to activate transmission modeling.
Nodal distribution technology capacity
For the specified node and the region containing it, fraction of the specified technology's capacity in the region that is assigned to the node.
Scenario database
Table: NodalDistributionTechnologyCapacity
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
n | text | Node |
t | text | Technology |
y | text | Year |
val | real | Fraction (0 to 1) |
Trade route
Indicator of whether region r can export a fuel to region rr. Trade routes establish export pathways that are not capacity-limited (for capacity-limited trading of fuels, use transmission lines).
Scenario database
Table: TradeRoute
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
r | text | First region connected by trade route |
rr | text | Second region connected by trade route |
f | text | Fuel |
y | text | Year |
val | real | Indicator (0 for no, 1 for yes) |
To enable two-way trade between two regions, two rows in TradeRoute are required. Each region should be r in one of the rows and rr in the other. Be sure to set val to 1 in both rows.
It is not necessary to populate zeros in TradeRoute for cases where trade is disallowed. NEMO assumes trade is not allowed unless a route is explicitly defined in the table.
Transmission availability factor
Fraction of time a transmission line is available to operate.
Scenario database
Table: TransmissionAvailabilityFactor
| Name | Type | Description |
|---|---|---|
tr | text | Transmission line |
l | text | Time slice |
y | text | Year |
val | real | Fraction (0 to 1) |
This parameter must be used when modeling transmission. If you don't want to represent reduced availability for lines, set a default of 1.0 for TransmissionAvailabilityFactor in the default parameters table or by using the setparamdefault function.
Transmission capacity to activity unit
Multiplier to convert 1 megawatt-year to a region's energy unit (e.g., 0.031536 if the energy unit is petajoules). This parameter is required if transmission modeling is enabled (see TransmissionModelingEnabled).
Scenario database
Table: TransmissionCapacityToActivityUnit
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
r | text | Region |
f | text | Fuel |
val | real | Multiplier |
Transmission maximum annual capacity investment
Maximum addition of endogenously determined capacity for a transmission line in a year. This parameter is scaled up to account for non-modeled years when selected years are calculated. It only applies to candidate transmission lines (lines without an exogenously specified construction date).
Scenario database
Table: TransmissionAnnualMaxCapacityInvestment
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
tr | text | Transmission line |
y | text | Year |
val | real | Capacity (MW) |
If a candidate transmission line's TransmissionAnnualMaxCapacityInvestment is less than its maxflow and you call calculatescenario with continuoustransmission = false, the line will never be built.
Transmission minimum annual capacity investment
Minimum addition of endogenously determined capacity for a transmission line in a year. This parameter is not scaled up to account for non-modeled years when selected years are calculated. It only applies to candidate transmission lines (lines without an exogenously specified construction date).
Scenario database
Table: TransmissionAnnualMinCapacityInvestment
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
tr | text | Transmission line |
y | text | Year |
val | real | Capacity (MW) |
If you set TransmissionAnnualMinCapacityInvestment for a candidate transmission line and year and call calculatescenario with continuoustransmission = false, the line will be built in its entirety in the specified year.
If you set TransmissionAnnualMinCapacityInvestment for a candidate transmission line in more than one year and call calculatescenario with continuoustransmission = false, your model will be infeasible.
If you set TransmissionAnnualMinCapacityInvestment for a candidate transmission line in more than one year and call calculatescenario with continuoustransmission = true, your model will be infeasible if the total minimum additions exceed the line's maxflow.
Transmission modeling enabled
Indicator of whether transmission modeling is enabled for a region, fuel, and year. The type field specifies the approach to simulating energy flow:
- 1 - Direct current optimized power flow (DCOPF) (classical formulation).[1]
- 2 - DCOPF with a disjunctive relaxation.[2]
- 3 - Pipeline flow. This approach treats transmission lines as pipelines whose flow is limited only by their maximum flow and efficiency.
If you choose type 1, NEMO will add a quadratic term to the optimization problem for your scenario. This will make the scenario incompatible with linear programming (LP)-only solvers such as GLPK and Cbc. To use DCOPF with an LP-only solver, choose type 2. This type produces equivalent results to type 1 but implements DCOPF with linear constraints.
If transmission modeling is enabled for a fuel, the fuel must be time-sliced (FUEL.timesliced = 1).
Scenario database
Table: TransmissionModelingEnabled
| Name | Type | Description |
|---|---|---|
id | integer | Unique identifier for row |
r | text | Region |
f | text | Fuel |
y | text | Year |
type | integer | Indicator (1, 2, or 3) |
You should not put rows in TransmissionModelingEnabled for regions/fuels/years for which you don't want to model transmission. NEMO does not support a type 0 for this parameter.
- 1See, e.g., Krishnan, V., Ho, J., Hobbs, B. F., Liu, A. L., McCalley, J. D., Shahidehpour, M. and Zheng, Q. P. (2016). Co-optimization of electricity transmission and generation resources for planning and policy analysis: review of concepts and modeling approaches. Energy Systems, 7(2). 297–332. DOI:10.1007/s12667-015-0158-4.
- 2Hui Zhang, Heydt, G. T., Vittal, V. and Mittelmann, H. D. (2012). Transmission expansion planning using an ac model: Formulations and possible relaxations. 2012 IEEE Power and Energy Society General Meeting 1–8. Proceedings of the 2012 IEEE Power & Energy Society General Meeting. New Energy Horizons - Opportunities and Challenges, San Diego, CA. IEEE. DOI:10.1109/PESGM.2012.6345410.