Shadow-day · stage 2 of 4 · intraday market
IDM re-clear · hour 04 · 2026-05-29
Stage status timestamp (IDM re-cleared): 2026-05-29T05:25:00Z
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
R832.05 / MWh
IDM SMP
R832.05 / MWh
Residual gap re-cleared
482.4 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 | -16.0% | 2518.7 | -481.3 | re-bid window → |
| Eskom Holdings — coal fleet (Generator) | 18203.0 | — | 18203.0 | — | — |
| IPP — wind plant (Generator) | 797.0 | -0.1% | 796.0 | -1.0 | — |
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) | 482.4 | R832.05 |
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=4 seed=42 [clearHour] tieBreak=price_asc → ts_asc → party_id_asc [clearHour] demand_mw_min=1320000 [clearHour] accept offer=o-04-renew-agg party=agg_renewables_01 price=38980c volume=180000 cumulative=180000 [clearHour] accept offer=o-04-wind party=gen_ipp_wind_01 price=45226c volume=47820 cumulative=227820 [clearHour] accept offer=o-04-coal party=gen_eskom_coal_01 price=83205c volume=1092180 cumulative=1320000 [clearHour] SMP=83205c marginal=gen_eskom_coal_01 — IDM — [reclearIntraday] day=2026-05-29 hour=4 seed=42 [reclearIntraday] slip party=agg_renewables_01 -16.0% dam=180000 revised=151121 gap+=28879 [reclearIntraday] slip party=gen_ipp_wind_01 -0.1% dam=47820 revised=47758 gap+=62 [reclearIntraday] residual_gap=28941 backfilled=28941 uncovered=0 idm_smp=83205c backfill_awards=1