GuildBuild Inc.
Reference build using public dataCurrent data

Ontario · Public IESO reports

Ontario Grid Reference

Demand, post-Market-Renewal zonal prices, official ICI tracker status, and a next-day reference model that remains hidden until measured gates pass.

Real-time zonal price is not a customer's final Ontario electricity price. This page is not an operational alert.

Ontario demand
12,364.9
MW · source Oct 19, 2026, 7:37 a.m. UTC
Real-time Ontario zonal price
$24.09
per MWh · source Oct 19, 2026, 7:37 a.m. UTC
Highest tracked demand
25,646.3
MW · tracker season 2026-05 to 2027-04
Day-ahead delivery
2026-10-19
Ontario zonal energy price schedule
Recent five-minute Ontario demandPopulated real-time intervals only. Blank future report intervals are not converted to zero.
  • Ontario demand (MW)
Recent five-minute Ontario demandPopulated real-time intervals only. Blank future report intervals are not converted to zero. Series use distinct line patterns and marker shapes. The exact values are available in the expandable table following the chart.
View exact values for Recent five-minute Ontario demand
Recent five-minute Ontario demand: exact values
Delivery intervalOntario demand (MW)
10-18 HE18/I1216149.4
10-18 HE19/I116317.5
10-18 HE19/I216338.5
10-18 HE19/I316278.4
10-18 HE19/I416245.4
10-18 HE19/I516203.4
10-18 HE19/I616174.4
10-18 HE19/I716132.4
10-18 HE19/I816240.4
10-18 HE19/I916189.4
10-18 HE19/I1016126.4
10-18 HE19/I1116220.4
10-18 HE19/I1216094.5
10-18 HE20/I115895.2
10-18 HE20/I215888.2
10-18 HE20/I315902.1
10-18 HE20/I415879.2
10-18 HE20/I515760.2
10-18 HE20/I615674.1
10-18 HE20/I715675.1
10-18 HE20/I815537.2
10-18 HE20/I915512.1
10-18 HE20/I1015377.1
10-18 HE21/I115114
10-18 HE21/I215144.1
10-18 HE21/I314983.1
10-18 HE21/I414929
10-18 HE21/I514976
10-18 HE21/I614902
10-18 HE21/I714724
10-18 HE21/I814660
10-18 HE21/I914660
10-18 HE21/I1014510
10-18 HE21/I1114527
10-18 HE22/I114326.2
10-18 HE22/I214436.8
10-18 HE22/I314436.8
10-18 HE22/I414391.2
10-18 HE22/I514327.6
10-18 HE22/I614282.7
10-18 HE22/I714176.4
10-18 HE22/I814144
10-18 HE22/I914158
10-18 HE22/I1014160
10-18 HE23/I113878.7
10-18 HE23/I213858.4
10-18 HE23/I313819.3
10-18 HE23/I413832
10-18 HE23/I513788.2
10-18 HE23/I613773.7
10-18 HE23/I713732.7
10-18 HE23/I813606.7
10-18 HE23/I913596.7
10-18 HE23/I1013729.3
10-18 HE23/I1113698
10-18 HE24/I113597.5
10-18 HE24/I213535.5
10-18 HE24/I313494.4
10-18 HE24/I413326.4
10-18 HE24/I513077.5
10-18 HE24/I612995.5
10-18 HE24/I713142.5
10-18 HE24/I813173.5
10-18 HE24/I913198.4
10-18 HE24/I1013258.4
10-18 HE24/I1113302.4
10-18 HE24/I1213185.4
10-19 HE1/I112835.7
10-19 HE1/I212930
10-19 HE1/I313182.9
10-19 HE1/I413100.7
10-19 HE1/I512920.2
10-19 HE1/I612918.2
10-19 HE1/I712917.4
10-19 HE1/I812965.6
10-19 HE1/I912848.6
10-19 HE1/I1012761.7
10-19 HE2/I112690.7
10-19 HE2/I212654.7
10-19 HE2/I312637.7
10-19 HE2/I412642.7
10-19 HE2/I512601.6
10-19 HE2/I612708.7
10-19 HE2/I712631.7
10-19 HE2/I812597.6
10-19 HE2/I912650.7
10-19 HE2/I1012546.7
10-19 HE3/I112533.9
10-19 HE3/I212482.9
10-19 HE3/I312555.9
10-19 HE3/I412629.9
10-19 HE3/I512596.9
10-19 HE3/I612591.9
10-19 HE3/I712517.9
10-19 HE3/I812551.9
10-19 HE3/I912364.9
Recent five-minute Ontario zonal pricePost-Market-Renewal real-time Ontario zonal energy prices. Negative and exact-zero observations are preserved.
  • Ontario zonal price (CAD/MWh)
Recent five-minute Ontario zonal pricePost-Market-Renewal real-time Ontario zonal energy prices. Negative and exact-zero observations are preserved. Series use distinct line patterns and marker shapes. The exact values are available in the expandable table following the chart.
View exact values for Recent five-minute Ontario zonal price
Recent five-minute Ontario zonal price: exact values
Delivery intervalOntario zonal price (CAD/MWh)
10-18 HE18/I1262.98
10-18 HE19/I165.65
10-18 HE19/I265.65
10-18 HE19/I365.64
10-18 HE19/I465.64
10-18 HE19/I563.66
10-18 HE19/I654.68
10-18 HE19/I752.4
10-18 HE19/I863.65
10-18 HE19/I954.1
10-18 HE19/I1052.34
10-18 HE19/I1152.66
10-18 HE19/I1248.23
10-18 HE20/I135.47
10-18 HE20/I234.57
10-18 HE20/I334.57
10-18 HE20/I434.56
10-18 HE20/I533.6
10-18 HE20/I633.09
10-18 HE20/I733.59
10-18 HE20/I832.66
10-18 HE20/I932.85
10-18 HE20/I1032.66
10-18 HE21/I136.84
10-18 HE21/I233.8
10-18 HE21/I332.81
10-18 HE21/I432.81
10-18 HE21/I532.89
10-18 HE21/I632.71
10-18 HE21/I732.62
10-18 HE21/I826.88
10-18 HE21/I925.46
10-18 HE21/I1024.15
10-18 HE21/I1124.15
10-18 HE22/I135.61
10-18 HE22/I233
10-18 HE22/I332.85
10-18 HE22/I432.74
10-18 HE22/I532.68
10-18 HE22/I632.68
10-18 HE22/I725.01
10-18 HE22/I824.65
10-18 HE22/I924.64
10-18 HE22/I1024.64
10-18 HE23/I124.85
10-18 HE23/I224.38
10-18 HE23/I324.61
10-18 HE23/I424.37
10-18 HE23/I524.37
10-18 HE23/I624.3
10-18 HE23/I724.29
10-18 HE23/I823.98
10-18 HE23/I923.99
10-18 HE23/I1024.37
10-18 HE23/I1124.6
10-18 HE24/I126.06
10-18 HE24/I224.97
10-18 HE24/I324.44
10-18 HE24/I414.88
10-18 HE24/I514.84
10-18 HE24/I614.67
10-18 HE24/I714.86
10-18 HE24/I814.87
10-18 HE24/I914.87
10-18 HE24/I1014.88
10-18 HE24/I1124.31
10-18 HE24/I1223.62
10-19 HE1/I114.68
10-19 HE1/I214.8
10-19 HE1/I324.68
10-19 HE1/I423.66
10-19 HE1/I514.81
10-19 HE1/I614.83
10-19 HE1/I714.83
10-19 HE1/I823.28
10-19 HE1/I914.82
10-19 HE1/I1014.8
10-19 HE2/I114.67
10-19 HE2/I214.66
10-19 HE2/I314.66
10-19 HE2/I414.67
10-19 HE2/I514.67
10-19 HE2/I614.69
10-19 HE2/I714.67
10-19 HE2/I814.67
10-19 HE2/I914.7
10-19 HE2/I1014.67
10-19 HE3/I130.92
10-19 HE3/I224.75
10-19 HE3/I325.8
10-19 HE3/I430.92
10-19 HE3/I530.92
10-19 HE3/I630.93
10-19 HE3/I730.93
10-19 HE3/I830.93
10-19 HE3/I924.09
Recent hourly demand historyOntario and market demand from the hourly Demand report.
  • Ontario demand (MW)
  • Market demand (MW)
Recent hourly demand historyOntario and market demand from the hourly Demand report. Series use distinct line patterns and marker shapes. The exact values are available in the expandable table following the chart.
View exact values for Recent hourly demand history
Recent hourly demand history: exact values
Delivery hourOntario demand (MW)Market demand (MW)
10-11 HE11302616190
10-11 HE21282116406
10-11 HE31265016046
10-11 HE41286716073
10-11 HE51293016151
10-11 HE61312016253
10-11 HE71355216390
10-11 HE81430216739
10-11 HE91492616742
10-11 HE101517016478
10-11 HE111541516801
10-11 HE121545417250
10-11 HE131563317680
10-11 HE141570117425
10-11 HE151587217352
10-11 HE161610017489
10-11 HE171583517529
10-11 HE181554917949
10-11 HE191549017821
10-11 HE201511617229
10-11 HE211475016906
10-11 HE221423916402
10-11 HE231379915989
10-11 HE241328615793
10-12 HE11312415554
10-12 HE21307315251
10-12 HE31271214893
10-12 HE41264815087
10-12 HE51267915464
10-12 HE61263816043
10-12 HE71318416681
10-12 HE81382816752
10-12 HE91447417012
10-12 HE101505717357
10-12 HE111547117738
10-12 HE121519017096
10-12 HE131505717031
10-12 HE141515917364
10-12 HE151533117837
10-12 HE161583218789
10-12 HE171635419971
10-12 HE181640820058
10-12 HE191640220289
10-12 HE201593319438
10-12 HE211525918714
10-12 HE221467318108
10-12 HE231414817418
10-12 HE241371717056
10-13 HE11369417142
10-13 HE21347517097
10-13 HE31345416955
10-13 HE41333016576
10-13 HE51348416703
10-13 HE61436517481
10-13 HE71585419073
10-13 HE81656119621
10-13 HE91684419329
10-13 HE101699619431
10-13 HE111710019254
10-13 HE121736319540
10-13 HE131755619432
10-13 HE141759019527
10-13 HE151791019605
10-13 HE161844520399
10-13 HE171889721094
10-13 HE181888820172
10-13 HE191866819856
10-13 HE201831719669
10-13 HE211773719594
10-13 HE221665018638
10-13 HE231553417675
10-13 HE241462517014
10-14 HE11424016721
10-14 HE21410216464
10-14 HE31402616006
10-14 HE41375615736
10-14 HE51436616776
10-14 HE61507817807
10-14 HE71615718640
10-14 HE81646818517
10-14 HE91648718259
10-14 HE101651717909
10-14 HE111673218621
10-14 HE121656518706
10-14 HE131658418921
10-14 HE141657519103
10-14 HE151644419152
10-14 HE161680119765
10-14 HE171709220368
10-14 HE181724020487
10-14 HE191741520574
10-14 HE201712020156
10-14 HE211650919157
10-14 HE221553618162
10-14 HE231483317340
10-14 HE241419516745
10-15 HE11405716668
10-15 HE21395216655
10-15 HE31376116365
10-15 HE41384016572
10-15 HE51403216903
10-15 HE61509217720
10-15 HE71635918939
10-15 HE81642018679
10-15 HE91639718579
10-15 HE101620118395
10-15 HE111604218229
10-15 HE121599418612
10-15 HE131600318641
10-15 HE141590518447
10-15 HE151622118407
10-15 HE161663618929
10-15 HE171692119511
10-15 HE181701819704
10-15 HE191692119339
10-15 HE201660919413
10-15 HE211617418706
10-15 HE221565318135
10-15 HE231468216945
10-15 HE241399616758
10-16 HE11376216813
10-16 HE21370016666
10-16 HE31353016638
10-16 HE41372716963
10-16 HE51414417178
10-16 HE61480217757
10-16 HE71608118830
10-16 HE81655519209
10-16 HE91678019166
10-16 HE101708319600
10-16 HE111731619885
10-16 HE121722219666
10-16 HE131708019372
10-16 HE141706219205
10-16 HE151675918919
10-16 HE161673419003
10-16 HE171685019725
10-16 HE181687319847
10-16 HE191696119843
10-16 HE201657919295
10-16 HE211603918658
10-16 HE221522217976
10-16 HE231468817581
10-16 HE241400917199
10-17 HE11398917265
10-17 HE21383117065
10-17 HE31372916774
10-17 HE41369116660
10-17 HE51390016958
10-17 HE61421017499
10-17 HE71496517934
10-17 HE81528917865
10-17 HE91519417165
10-17 HE101503616702
10-17 HE111473916328
10-17 HE121442215933
10-17 HE131410715815
10-17 HE141392415667
10-17 HE151393415924
10-17 HE161449016082
10-17 HE171539717690
10-17 HE181597118593
10-17 HE191622319136
10-17 HE201580918694
10-17 HE211526918026
10-17 HE221468017571
10-17 HE231402117101
10-17 HE241341816563
10-18 HE11350016798
Day-ahead Ontario zonal priceHourly total zonal price together with its loss and congestion components from the day-ahead Ontario zonal price report.
  • Zonal price (CAD/MWh)
  • Loss component (CAD/MWh)
  • Congestion component (CAD/MWh)
Day-ahead Ontario zonal priceHourly total zonal price together with its loss and congestion components from the day-ahead Ontario zonal price report. Series use distinct line patterns and marker shapes. The exact values are available in the expandable table following the chart.
View exact values for Day-ahead Ontario zonal price
Day-ahead Ontario zonal price: exact values
Hour endingZonal price (CAD/MWh)Loss component (CAD/MWh)Congestion component (CAD/MWh)
HE133.710.240
HE235.350.320
HE335.370.340
HE437.380.350
HE546.980.370
HE671.430.39-0.03
HE796.960.350
HE892.160.290
HE972.560.320
HE1066.620.330
HE1170.750.250
HE1261.350.170
HE1347.990.16-0.22
HE1449.740.110
HE1552.790.10
HE1661.540.020
HE17100.25-0.120
HE18126.32-0.1-0.01
HE19105.96-0.110.07
HE2099.98-0.290
HE21100.27-0.090
HE2292.150.050
HE2359.190.20
HE2448.470.340

Official status retained

ICI Ontario demand peak tracker

Initial and Preliminary entries are not treated as Final. This table is a public reference, not a curtailment signal.

Official ICI peak tracker entries
RankDelivery dateHour endingOntario demand (MW)Status
12026-07-141725,646.3Final
22026-07-021824,733.8Final
32026-07-131823,982.3Final
42026-07-031723,856.7Final
52026-07-011423,833.1Final
62026-06-301923,526Final
72026-07-311723,381.3Final
82026-07-081923,254.6Final
92026-08-101723,142.3Final
102026-08-051823,014.7Final

price-attribution-levels-v1

Today's price, decomposed

Across 29 populated intervals on 2026-10-19, the mean zonal price of $20.07 per MWh was composed of an energy component of $19.90, a loss component of $0.18, and a congestion component of $0.00. The congestion component accounted for its largest hourly mean, $0.00, in HE1.

Hourly mean price decomposition (levels; components sum to the zonal price exactly). Decomposition is arithmetic, not a causal claim.
Hour endingZonalEnergyLossCongestionIntervals
HE1$17.52$17.40$0.12$0.0010
HE2$14.67$14.53$0.14$0.0010
HE3$28.91$28.63$0.28$0.009

demand-vs-baselines-v1

Current demand, compared with named baselines

Current demand of 12,365 MW (HE3, 2026-10-19), compared with:

Median of the same hour on the last four same-weekday days (n=4)
12,944 MW (-579 MW vs baseline) — sample includes Ontario statutory holiday(s): 2026-10-12
Same hour yesterday (2026-10-17; different weekday)
13,729 MW (-1,364 MW vs baseline)
Typical range of the past 120 days for this hour (weekday days, n=85 hours)
P10 13,212 MW to P90 16,060 MW — current demand is below the range. About one in five historical hours falls outside this range by construction; being outside it is a comparison, not an anomaly claim.

ici-proximity-v1

Today's maximum vs this season's tracked peaks

Today's highest populated demand reading was 13,183 MW. The 10th-ranked tracked peak this season is 23,015 MW — a gap of 9,832 MW below today's maximum. Today's maximum exceeded 0 of the 10 tracked peaks and sits at the 0th percentile of that distribution — the share of tracked peaks at or below it (reference set: this season's tracked peaks).

Backward-looking comparison of recorded values only. The tracker's Initial and Preliminary entries are not settled determinations, and the top-10 watchlist is broader than the five coincident peaks that set Class A peak demand factors.

Methodology

Reference formulas and explicit exclusions.

Real-time demand and zonal-price intervals join only on matching delivery date, hour ending, and five-minute interval. Blank future values remain absent; zero and negative prices remain unchanged.

The next-day model takes the median for each hour from the prior four matching weekdays, adjusted by a recent-level ratio capped at 0.90–1.10. The ratio is the mean demand on the latest complete day divided by the mean demand on the complete day seven days earlier. Rolling-origin evaluation uses the prior 60 calendar days against a same-hour-seven-days-ago baseline, without target-day or future observations.

Zonal energy price is one market component, not a customer's final bill. ICI tracker entries and the model are never operational alerts, settlement calculations, or facility curtailment advice.

Provenance

Sources, timestamps, and licence notes

Read the versioned JSON dataset endpoint. Source “data as of” timestamps are distinct from GuildBuild fetch times.

IESO day-ahead hourly Ontario zonal energy price

Data as of
Oct 18, 2026, 5:31 p.m. UTC
Fetched
Oct 18, 2026, 6:23 p.m. UTC
Unit
CAD/MWh

Copyright © 2004-2022 Independent Electricity System Operator, all rights reserved. This information is subject to the Terms of Use set out in the IESO’s website (www.ieso.ca). GuildBuild transformed the public report and is solely responsible for this reference build; IESO does not endorse or warrant it.

Source Terms / licence

IESO hourly demand report

Data as of
Oct 18, 2026, 5:00 a.m. UTC
Fetched
Oct 18, 2026, 3:23 p.m. UTC
Unit
MW

Copyright © 2004-2022 Independent Electricity System Operator, all rights reserved. This information is subject to the Terms of Use set out in the IESO’s website (www.ieso.ca). GuildBuild transformed the public report and is solely responsible for this reference build; IESO does not endorse or warrant it.

Source Terms / licence

IESO Industrial Conservation Initiative Ontario Demand Peak Tracker

Data as of
Oct 19, 2026, 7:10 a.m. UTC
Fetched
Oct 19, 2026, 7:40 a.m. UTC
Unit
MW

Copyright © 2004-2022 Independent Electricity System Operator, all rights reserved. This information is subject to the Terms of Use set out in the IESO’s website (www.ieso.ca). GuildBuild transformed the public report and is solely responsible for this reference build; IESO does not endorse or warrant it.

Source Terms / licence

IESO RealtimeTotals Ontario demand

Data as of
Oct 19, 2026, 7:37 a.m. UTC
Fetched
Oct 19, 2026, 7:40 a.m. UTC
Unit
MW

Copyright © 2004-2022 Independent Electricity System Operator, all rights reserved. This information is subject to the Terms of Use set out in the IESO’s website (www.ieso.ca). GuildBuild transformed the public report and is solely responsible for this reference build; IESO does not endorse or warrant it.

Source Terms / licence

IESO real-time Ontario zonal energy price

Data as of
Oct 19, 2026, 7:37 a.m. UTC
Fetched
Oct 19, 2026, 7:40 a.m. UTC
Unit
CAD/MWh

Copyright © 2004-2022 Independent Electricity System Operator, all rights reserved. This information is subject to the Terms of Use set out in the IESO’s website (www.ieso.ca). GuildBuild transformed the public report and is solely responsible for this reference build; IESO does not endorse or warrant it.

Source Terms / licence

Ask about the public methodology