Shadow-day · stage 2 of 4 · intraday market
IDM re-clear · hour 21 · 2026-05-29
Stage status timestamp (IDM re-cleared): 2026-05-29T22:25:00Z
Illustrative re-clearing — production MMS runs a full intraday SCED. The IDM stage consumes the DAM result for this hour, applies each variable generator's revised forecast, and re-clears the residual gap.
DAM SMP
R864.37 / MWh
IDM SMP
R864.37 / MWh
Residual gap re-cleared
403.1 MWh
from forecast slip on variable plant
Forecast adjustments at the IDM gate
Variable generators (wind / solar / aggregated renewables) revise availability; a slip beyond −5% makes the seller IDM re-bid eligible (the forecast-slip story). Dispatchable plant shows 0% slip.
| Party | DAM award (MWh) | Forecast slip | Revised (MWh) | Gap (MWh) | Re-bid? |
|---|---|---|---|---|---|
| Aggregator — renewables pool | 3000.0 | -13.4% | 2596.9 | -403.1 | re-bid window → |
| Eskom Holdings — coal fleet (Generator) | 21635.0 | — | 21635.0 | — | — |
| IPP — wind plant (Generator) | 1365.0 | 0.2% | 1367.5 | — | — |
IDM backfill awards
Supply re-dispatched to cover the residual gap, paid at the IDM SMP.
| Party | MWh | Price (R/MWh) |
|---|---|---|
| Eskom Holdings — coal fleet (Generator) | 403.1 | R864.37 |
Commit this IDM re-clear to the append-only SHA-256 chain
(idm_re_cleared event). Best-effort: with no D1 binding bound
locally this degrades to a "not recorded" marker rather than failing.
Full DAM + IDM transcript
[clearHour] day=2026-05-29 hour=21 seed=42 [clearHour] tieBreak=price_asc → ts_asc → party_id_asc [clearHour] demand_mw_min=1560000 [clearHour] accept offer=o-21-renew-agg party=agg_renewables_01 price=38214c volume=180000 cumulative=180000 [clearHour] accept offer=o-21-wind party=gen_ipp_wind_01 price=46372c volume=81900 cumulative=261900 [clearHour] accept offer=o-21-coal party=gen_eskom_coal_01 price=86437c volume=1298100 cumulative=1560000 [clearHour] SMP=86437c marginal=gen_eskom_coal_01 — IDM — [reclearIntraday] day=2026-05-29 hour=21 seed=42 [reclearIntraday] slip party=agg_renewables_01 -13.4% dam=180000 revised=155817 gap+=24183 [reclearIntraday] residual_gap=24183 backfilled=24183 uncovered=0 idm_smp=86437c backfill_awards=1