Shadow-day · L4 · seller forecast-slip → IDM re-bid
IPP — wind plant (Generator) — IDM re-bid window
gen_ipp_wind_01
When a variable plant's day-ahead forecast slips beyond −5% at the IDM gate, the seller can re-bid in the intraday market rather than fall straight into the (more expensive) balancing/imbalance settlement.
Hours forecast slipped
21 / 24
Total shortfall (do nothing)
2832.5 MWh
Imbalance bill if no re-bid
R5968871.39
priced at the §07 under-delivery premium
Re-bid window · hour 06
IDM gate timestamp: 2026-05-29T07:25:00Z
Day-ahead award 1012.0 MWh; forecast slipped -19.7% to 812.5 MWh available — a shortfall of 199.5 MWh. Do nothing and the imbalance bill is R398966.67. There is 206.0 MWh of residual demand to re-bid into at an IDM SMP of R842.14/MWh.
24-hour forecast-slip ledger
| Hr | DAM award | Slip | Revised | Shortfall | Imbalance (do nothing) | Re-bid? |
|---|---|---|---|---|---|---|
| 00 | 1501.0 | 0.8% | 1513.3 | — | — | — |
| 01 | 1531.0 | -4.6% | 1460.4 | 70.6 | R141200.00 | — |
| 02 | 997.0 | -0.8% | 989.4 | 7.7 | R15300.00 | — |
| 03 | 814.0 | -11.5% | 720.1 | 93.9 | R187866.67 | eligible |
| 04 | 1413.0 | -0.1% | 1411.2 | 1.8 | R3666.67 | — |
| 05 | 1312.0 | -7.8% | 1210.1 | 101.9 | R203866.67 | eligible |
| 06 | 1012.0 | -19.7% | 812.5 | 199.5 | R398966.67 | eligible |
| 07 | 1116.0 | -1.9% | 1094.7 | 21.3 | R42533.33 | — |
| 08 | 1930.0 | -13.3% | 1673.8 | 256.1 | R512300.00 | eligible |
| 09 | 1352.0 | -11.6% | 1195.7 | 156.3 | R312600.00 | eligible |
| 10 | 1633.0 | -14.9% | 1388.9 | 244.1 | R488200.00 | eligible |
| 11 | 1895.0 | -7.7% | 1749.0 | 145.9 | R291900.00 | eligible |
| 12 | 1119.0 | -14.9% | 952.5 | 166.5 | R333000.00 | eligible |
| 13 | 1432.0 | -18.0% | 1174.5 | 257.5 | R515066.67 | eligible |
| 14 | 867.0 | 2.7% | 890.4 | — | — | — |
| 15 | 1625.0 | -9.2% | 1474.8 | 150.2 | R300400.00 | eligible |
| 16 | 1536.0 | -5.8% | 1447.4 | 88.6 | R177200.00 | eligible |
| 17 | 1212.0 | -8.9% | 1104.0 | 108.0 | R271918.63 | eligible |
| 18 | 1505.0 | -17.2% | 1246.1 | 258.9 | R652531.56 | eligible |
| 19 | 1094.0 | -12.9% | 952.3 | 141.7 | R361599.92 | eligible |
| 20 | 955.0 | -7.0% | 888.5 | 66.5 | R168121.27 | eligible |
| 21 | 1608.0 | 0.2% | 1611.0 | — | — | — |
| 22 | 1433.0 | -12.9% | 1248.3 | 184.7 | R369433.33 | eligible |
| 23 | 1026.0 | -10.8% | 915.4 | 110.6 | R221200.00 | eligible |