Input files are comma separated text files (CSV), with a comma as delimiter and period as the decimal symbol. The first line in the files contains a header, with unique keys associated with each column. The ordering of columns is arbitrary. Keys are case sensitive and should be all lower case. Columns labelled OPT are optional.
There are 5 input files associated with nodes, AC branches, DC branches, consumers and generators. These files contain references to additional files which have information about normalised storage values, energy inflow profiles and power demand profiles. The reference identifier (integer number or string) in the generator and consumer files should match an identifier in the relevant storage value or profile files.
Nodes need to have unique identifier strings. Area information is used for scenario generation (preprocessing), and for plotting and presentation of results. Latitude and longitude information is only used for plotting the grid on a map.
| column key | description | type | units |
|---|---|---|---|
| "id" | Unique string identifier | string | |
| "lat" | Latitude | float | degrees |
| "lon" | Longitude | float | degrees |
| "area" | Area/country code | string |
Branches have from and to references that must match a node identifier in the list of nodes. Impedance should be given as per unit system with the base power being the global one (powergama.constants.baseS).
| column key | description | type | units |
|---|---|---|---|
| "node_from" | Node identifier | string | |
| "node_to" | Node identifier | string | |
| "reactance" | Reactance | float | p.u |
| "resistance" | Resistance (OPT) | float | p.u. |
| "capacity" | Capacity | float | MW |
DC branches have from and to references that must match a node identifier in the list of nodes.
| column key | description | type | units |
|---|---|---|---|
| "node_from" | Node identifier | string | |
| "node_to" | Node identifier | string | |
| "capacity" | Capacity | float | MW |
Consumers are loads connected to nodes. There may be any number of consumers per node, although zero or one is typical.
demand_avg gives the average demand, which is easily computed from the
annual demand if necessary. demand_ref gives the name of the demand
profile which gives the variation over time. Demand profiles should be
normalised and have an annual average of 1.
| column key | description | type | units |
|---|---|---|---|
| "node" | Node identifier | string | |
| "demand_avg" | Average demand | float | MW |
| "demand_ref" | Profile reference | string | |
| "flex_fraction" | Fraction of demand which is flexible (OPT) | float | |
| "flex_on_off" | Flexibility on/off ratio (OPT) | float | |
| "flex_storage" | Maximum flexibility (OPT) | float | MWh |
| "flex_storval_filling" | Profile ref, storage value filling dependence (OPT) | string | |
| "flex_storval_time" | Profile ref, storage value time dependence (OPT) | string | |
| "flex_basevalue" | Base storage value (OPT) | float | €/MWh |
Generators are the most complex data structure and require the most input data. The three columns related to pumping only need to be filled out if the pumping capacity is non-zero.
| column key | description | type | units |
|---|---|---|---|
| "node" | Node identifier | string | |
| "desc" | Description or name | string | |
| "type" | Generator type | string | |
| "pmax" | Maximum production | float | MW |
| "pmin" | Minimum production | float | MW |
| "fuelcost" | Cost of generation | float | €/MWh |
| "inflow_fac" | Inflow factor | float | |
| "inflow_ref" | Inflow profile reference | string | |
| "storage_cap" | Storage capacity | float | MWh |
| "storage_price" | Base for storage value | float | €/MWh |
| "storval_filling_ref" | Profile ref, storage value filling level dependence | string | |
| "storval_time_ref" | Profile ref, storage value time dependence | string | |
| "storage_ini" | Initial storage filling level | float | 1 |
| "pump_cap" | Pumping capacity (OPT) | float | MW |
| "pump_efficiency" | Pumping efficiency (OPT) | float | |
| "pump_deadband" | Pumping price dead-band (OPT) | float | €/MWh |
node is the string identifier of the node where the generator is
connected. There may be any number of generators per node. pmax is the
maximum power production, i.e. the generator capacity. pmin is the
minimum power production. This is normally zero, but may be nonzero for
certain generator types such as nuclear power generators. fuelcost is
the cost of generation. For generators without storage, the marginal
cost is set equal to this value. storage_price is the base
value for storage generator's storage values. It sets the absolute scale
in the storage value calculation. storage_capacity is the capacity of
the storage system. This is usually relevant only for hydro power and
solar CSP. storagevalue_ref is the string identifier of the associated
storage value table to be used for this generator/storage system
storage_init is the initial relative filling level of the storage.
inflow_fac is the inflow factor. inflow_ref is the string identifier
of the associated inflow profile.
Power inflow at a given timestep
In case the annual inflow is known, the inflow factor can be expressed by integrating the above equation, giving
There are two typical ways to use inflow factor and inflow profile:
-
Normalised inflow profile with maximum value = 1: profile gives power output per installed capacity, with average value equal to the capacity factor of the generator. In this case,
inflow_factorshould be approximately 1, larger for good sites and smaller for bad sites. If inflow factor is larger than one, then at times$P_\text{inflow}>P_\text{max}$ . -
Normalised inflow profile with average value = 1:
inflow_factoris equal to capacity factor, i.e. average inflow divided by generator capacity. Typical capacity factors are 0.5 for a large hydro storage system, 0.25 for wind power, and 0.22 for solar PV.
It is important to keep in mind that if the generator capacity is upgraded without the energy inflow changing (which may be relevant if there is storage), the inflow factor must be reduced correspondingly.
If fine resolution is not needed, many generators may use the same profile, but with different inflow factors to get representative capacity factors.
The following quantities vary with time:
-
Generator power inflow (wind, solar radiation, rain)
-
Consumer load (power demand)
-
Storage values
For these, there are two fields in the input data, one parameter that gives the absolute scale, and a reference to a normalised profile which entails the time profile. Multiplied together these give the absolute variation over time, as expressed e.g. in the inflow equation above. The reason for this splitting between absolute scale and normalised profile is to enable multiple references to the same profile (e.g. normalised profile for demand may be the same for all consumers within an area), and to simplify the task of creating scenarios by scaling up or down the absolute scale without the need to change the profile time series.
Power inflow is given by weather conditions. Hydro has mainly a seasonal profile, whereas wind and solar varies from hour to hour. Solar has a characteristic daily profile with no production in dark hours. As stated previously, there are two alternative ways to specify inflow profile and absolute scale (inflow factor): 1) The profile is normalised to give power inflow per installed capacity (with average value representing the capacity factor), and absolute scale is nominally equal to one; 2) The profile is normalised to have an average value of unity, and absolute scale represents the capacity factor.
| column key | description | type | units |
|---|---|---|---|
| identifier1 | values type 1 | float | MW |
| identifier2 | values type 2 | float | MW |
| ... |
There is one row per time step.
There are two dependencies:
-
Filling level
-
Time of year and time of day
All in all, the storage values are computed according to
where
Time dependence of storage values reflect the time dependence of the associated inflow, and is therefore quite different for hydro (seasonal variation) and CSP (daily variation). This dependency is given in the same format as for inflow and consumption, see above.
Storage value dependence on filling level is specified as follows:
| column key | description | type | units |
|---|---|---|---|
| identifier1 | values type 1 | float | €/MWh |
| identifier2 | values type 2 | float | €/MWh |
| ... |
There is one row per percentile (filling level)