Shadow-day · stage 2 of 4 · intraday market
IDM re-clear · hour 20 · 2026-05-29
Stage status timestamp (IDM re-cleared): 2026-05-29T21:25:00Z
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
R1088.33 / MWh
IDM SMP
R1088.33 / MWh
Residual gap re-cleared
270.1 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 | -4.7% | 2860.0 | -140.0 | — |
| IPP — battery storage (BESS) (Generator) | 1132.0 | — | 1132.0 | — | — |
| Eskom Holdings — coal fleet (Generator) | 30000.0 | — | 30000.0 | — | — |
| IPP — wind plant (Generator) | 1868.0 | -7.0% | 1737.8 | -130.2 | re-bid window → |
IDM backfill awards
Supply re-dispatched to cover the residual gap, paid at the IDM SMP.
| Party | MWh | Price (R/MWh) |
|---|---|---|
| IPP — battery storage (BESS) (Generator) | 270.1 | R1088.33 |
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=20 seed=42 [clearHour] tieBreak=price_asc → ts_asc → party_id_asc [clearHour] demand_mw_min=2160000 [clearHour] accept offer=o-20-renew-agg party=agg_renewables_01 price=41230c volume=180000 cumulative=180000 [clearHour] accept offer=o-20-wind party=gen_ipp_wind_01 price=43586c volume=112080 cumulative=292080 [clearHour] accept offer=o-20-coal party=gen_eskom_coal_01 price=84800c volume=1800000 cumulative=2092080 [clearHour] accept offer=o-20-bess party=gen_bess_ipp_01 price=108833c volume=67920 cumulative=2160000 [clearHour] SMP=108833c marginal=gen_bess_ipp_01 — IDM — [reclearIntraday] day=2026-05-29 hour=20 seed=42 [reclearIntraday] slip party=agg_renewables_01 -4.7% dam=180000 revised=171601 gap+=8399 [reclearIntraday] slip party=gen_ipp_wind_01 -7.0% dam=112080 revised=104271 gap+=7809 [reclearIntraday] residual_gap=16208 backfilled=16208 uncovered=0 idm_smp=108833c backfill_awards=1