(efi_pref)=

# Coupling market steps and thermal generation

Individual loads like industrial loads and thermal units are specified by a capacity and corresponding marginal cost. A load step or a thermal unit step can represent either an individual unit or a sum of individual units. Therefore, these load or generation steps can be connected to a set of busbars. These connections are defined in the file `EFI-PREF.DAT`.

For each area in the market model, the number of steps is specified first. This is followed by a line for every step comprising the name of the step, the number busbars it is connected to, and then the busbar and corresponding share of the load or generation at this busbar.

In this file the following is specified for **each area**:

- Header counter (Number of market steps connected to busbars)
- market step parameters

## Header counter

Number of market steps connected to busbars

Record format:

```text
<The number of market steps connected to busbars>,
```

Example:

```text
8,
```

## Market step parameters

Number of entries must match the header counter.

Record format:

```text
<Market step name>,<Number of connections>,<Busbarnumber1>, <Weight1>, <Busbarnumber2>, <Weight2>, ...
```
Fields:
- 1: Market step name
- 2: Number of busbars the market step is connected to
- 3: Busbar number 1
- 4: Weight 2
- 5: Busbar number 2
- 6: Weight 2
- 7: ... busbar and weight distribution continues

Example:

```text
VARMEKRAFT 1,   1,10005,    1.000000,
VARMEKRAFT 2,   2,10006,    0.3, 10007, 0.7
```
## Example complete file

```
CC,------------------------------------------------------------
CC,    Delomr�de   1                                        ---
CC,------------------------------------------------------------
   8,
Rasjonering,   1,   0,    1.000000,
VARMEKRAFT 1,   1,10005,    1.000000,
VARMEKRAFT 2,   1,10005,    1.000000,
VARMEKRAFT 3,   1,10005,    1.000000,
VARMEKRAFT 4,   1,10005,    1.000000,
VARMEKRAFT 5,   1,10005,    1.000000,
VARMEKRAFT 6,   1,10005,    1.000000,
VARMEKRAFT 7,   1,10005,    1.000000,
CC,------------------------------------------------------------
CC,    Delomr�de   2                                        ---
CC,------------------------------------------------------------
   3,
KJELKRAFT 25 \RE,   1,20010,    1.000000,
KRAFT UTEN MARKED,   1,20010,    1.000000,
Rasjonering,   1,   0,    1.000000,
CC,------------------------------------------------------------
CC,    Delomr�de   3                                        ---
CC,------------------------------------------------------------
   8,
EXCH otra-term,   1,30019,    1.000000,
Rasjonering,   1,   0,    1.000000,
VARMEKRAFT - 1,   1,30017,    1.000000,
VARMEKRAFT - 2,   1,30017,    1.000000,
VARMEKRAFT - 3,   1,30017,    1.000000,
VARMEKRAFT - 4,   1,30017,    1.000000,
VARMEKRAFT - 5,   1,30017,    1.000000,
VARMEKRAFT - 6,   1,30017,    1.000000,
CC
FILNAVN=
CC
```

| Note |
|-|
| One or several steps can have been left out of the file, either by mistake or deliberately because there is no known information about the step and connection. In these cases, the area firm load is modified accordingly, either by adding load or subtracting generation. The firm load is distributed according to busbar shares provided in EFI-FAST.dat. |
| In the case of zero share for all defined busbars it is assumed an equal share. |
| For each step, all busbar weights are accumulated and relative shares for each busbar are computed. If the same busbar is listed several times, its weights are accumulated.|
| In case a bus number is set to 0 or -1, the corresponding trade is subtracted/added from/to the firm load in the area.|