Table 1
A list of power/energy systems modelling tools, including PowNet. These tools are categorized based on their operational coverage and representation of the transmission networks. The tools under the first group are generally suitable for short-term grid operations; they do not consider the unit commitment problem. Commercial software is indicated in italic.
| Group | Software/tools | Functionalities |
|---|---|---|
| 1 | MATPOWER [15], pandapower [16], PYPOWER [17], PowerFactory [18], PowerWorld [19] | Short-term grid operations without unit commitment |
| 2 | GENESYS [20], UC/ED [21], CAPOW [22], urbs [23], PROMOD [24] | Unit commitment with no or lumped representation of transmission networks |
| 3 | PSAT [13], PyPSA [5], PowNet, PLEXOS [25] | Unit commitment with full representation of transmission networks |
Figure 1
Graphical representation of PowNet. Black and red boxes represent input and output elements, respectively. Grey boxes represent elements not included in the model.
Figure 2
Main generation and transmission components of the Cambodian power system, as of 2016. The dashed lines denote components that are either planned or under construction.
Table 2
Notations used to describe PowNet.
| Indices and sets | |
|---|---|
| n | any node in the system |
| N | set of all nodes in the system |
| g | dispatchable unit |
| G | set of all dispatchable units |
| i | import node |
| I | set of all import nodes |
| rn | variable renewable resource (e.g., hydro, wind, solar) |
| RN | set of all variable renewable resources |
| k | sink node connected by the transmission line to any node n |
| t | time-step (hour, h) |
| T | planning horizon (e.g., 24 h) |
| Parameters of the dispatchable units (g) | |
| MaxCapg | maximum capacity (MW) |
| MinCapg | minimum capacity (MW) |
| FixedCostg | fixed O&M cost ($) |
| StartCostg | start-up cost ($/start) |
| HeatRateg | heat rate (MMBtu/MWh) |
| FuelPriceg | price of fuel ($/MMBtu) |
| VarCostg | variable O&M cost ($/MWh) |
| Rampg | ramping limit (MW/h) |
| MinUpTimeg | minimum up time (h) |
| MinDownTimeg | minimum down time (h) |
| Parameters of the import nodes (i) | |
| MaxCapi | maximum allowable import (MW) |
| ImportPricei | price of imported electricity ($/MWh) |
| Parameters of the transmission network | |
| LineSusn,k | susceptance (Siemens) of the transmission line between nodes n and k |
| LineCapn,k | capacity (MW) of the transmission line between nodes n and k |
| Input time series (hourly) | |
| RenewAvailrn,t | available electricity (MWh) from the rn-th renewable resource |
| Demandn,t | electricity demand (MWh) (or export) at any node n |
| Decision variables (at each hour t) | |
| ONg,t | binary (0,1) variable indicating if unit g is online (1) or offline (0) |
| Switchg,t | binary (0,1) variable indicating if unit g must be started-up (Switchg,t =1 only when ONg,t-1 = 0 is followed by ONg,t = 1) |
| Elecg*,t | electricity (MWh) generated by dispatchable unit g (*or any other powerplant) |
| VoltAnglen,t | voltage angle (radian) at any node n |
| SpinResg,t | spinning reserve (MWh) at unit g |
| NonSpinResg,t | non-spinning reserve (MWh) at unit g |
Figure 3
Daily generation mix for 2016.
Figure 4
Annual average usage of the transmission lines, expressed as a percentage of the lines’ capacity. The radar chart shows the monthly average and maximum usage of the line connecting Kampot to Takoe (one of the lines with relatively high usage).
Figure 5
Simulation results obtained with the ‘existing’ and ‘altered’ transmission networks. System’s performance is measured in terms of generation mix, electricity shortage, operating costs, and CO2 emissions.
Table B1
Design specifications of the Cambodian hydropower dams.
| Name | Installed capacity | Dam height | Storage | Design discharge | Hydraulic head | Basin area | Runoff coefficient |
|---|---|---|---|---|---|---|---|
| (MW) | (m) | (Mm3) | (m3/s) | (m) | (km2) | ||
| Kamchay | 194.1 | 110 | 680 | 163.5 | 122 | 710 | 0.62 |
| Kirirom I | 12 | 34 | 30 | 20 | 373.5 | 99 | 0.48 |
| Kirirom III | 18 | 40 | 30 | 40 | 271 | 105 | 0.48 |
| L.R. Chrum | 338 | 68 | 62 | 300 | 132 | 1,550 | 0.51 |
| Stung Atay | 240 | 45 | 443.8 | 125 | 216 | 1,157 | 0.75 |
| Stung Tatay | 246 | 77 | 322 | 150 | 188 | 1,073 | 0.71 |