Phase 1 shadow · synthetic · independent  ·  SAWEM Phase 1 Trading Simulator — explainer-grade, not an MMS.  ·  Built from the publicly available Trading Rules; Round 2 not yet gazetted
Trading day 2026-05-29 virtual hour 00 Auction state: ACCEPTING gate close in 18h:00m DAM clear IDM re-clear Balancing Settlement
SAWEM
Shadow-day · stage 2 of 4 · intraday market

IDM re-clear · hour 14 · 2026-05-29

Stage status timestamp (IDM re-cleared): 2026-05-29T15:25:00Z

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
R849.56 / MWh
IDM SMP
R849.56 / MWh
Residual gap re-cleared
110.2 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 -3.7% 2889.8 -110.2
Eskom Holdings — coal fleet (Generator) 24905.0 24905.0
IPP — solar BW5 (Generator) 1590.0 3.0% 1637.3
IPP — wind plant (Generator) 1505.0 2.7% 1545.5

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) 110.2 R849.56
Audit chain

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=14 seed=42
[clearHour] tieBreak=price_asc → ts_asc → party_id_asc
[clearHour] demand_mw_min=1860000
[clearHour] accept offer=o-14-solar party=gen_ipp_solar_bw5_01 price=36189c volume=95400 cumulative=95400
[clearHour] accept offer=o-14-renew-agg party=agg_renewables_01 price=40822c volume=180000 cumulative=275400
[clearHour] accept offer=o-14-wind party=gen_ipp_wind_01 price=43736c volume=90300 cumulative=365700
[clearHour] accept offer=o-14-coal party=gen_eskom_coal_01 price=84956c volume=1494300 cumulative=1860000
[clearHour] SMP=84956c marginal=gen_eskom_coal_01
— IDM —
[reclearIntraday] day=2026-05-29 hour=14 seed=42
[reclearIntraday] slip party=agg_renewables_01 -3.7% dam=180000 revised=173389 gap+=6611
[reclearIntraday] residual_gap=6611 backfilled=6611 uncovered=0 idm_smp=84956c backfill_awards=1
Shadow-day stage 2/4 · Trading Rules R2 §07 (intraday) · simulator build 2026-05-29.