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 07 · 2026-05-29

Stage status timestamp (IDM re-cleared): 2026-05-29T08:25:00Z

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
R854.47 / MWh
IDM SMP
R854.47 / MWh
Residual gap re-cleared
320.1 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 -9.8% 2705.6 -294.4 re-bid window →
Eskom Holdings — coal fleet (Generator) 23241.0 23241.0
IPP — solar BW5 (Generator) 407.0 3.4% 420.9
IPP — wind plant (Generator) 1352.0 -1.9% 1326.2 -25.8

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) 320.1 R854.47
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=7 seed=42
[clearHour] tieBreak=price_asc → ts_asc → party_id_asc
[clearHour] demand_mw_min=1680000
[clearHour] accept offer=o-07-solar party=gen_ipp_solar_bw5_01 price=36310c volume=24420 cumulative=24420
[clearHour] accept offer=o-07-renew-agg party=agg_renewables_01 price=40878c volume=180000 cumulative=204420
[clearHour] accept offer=o-07-wind party=gen_ipp_wind_01 price=46598c volume=81120 cumulative=285540
[clearHour] accept offer=o-07-coal party=gen_eskom_coal_01 price=85447c volume=1394460 cumulative=1680000
[clearHour] SMP=85447c marginal=gen_eskom_coal_01
— IDM —
[reclearIntraday] day=2026-05-29 hour=7 seed=42
[reclearIntraday] slip party=agg_renewables_01 -9.8% dam=180000 revised=162337 gap+=17663
[reclearIntraday] slip party=gen_ipp_wind_01 -1.9% dam=81120 revised=79574 gap+=1546
[reclearIntraday] residual_gap=19209 backfilled=19209 uncovered=0 idm_smp=85447c backfill_awards=1
Shadow-day stage 2/4 · Trading Rules R2 §07 (intraday) · simulator build 2026-05-29.