Two utilities. One storm system. One restored 99% of customers in five days. The other is finishing on day fourteen. The difference is not the outage — it’s the restoration curve, and that’s the number your standby plan is actually built against.
Restoration figures current as of August 24, 2026, and sourced from NIPSCO and ComEd public reporting. Outage counts continue to change.
Where things stand, two weeks in
On August 11, 2026, a derecho tore across northern Illinois and Northwest Indiana. The National Weather Service recorded a 99 mph gust in Gary — comparable to a Category 2 hurricane.
Northern Indiana Public Service Company (NIPSCO). The utility has called this the largest and most widespread outage event in its history. At peak, roughly 301,000 customers lost service — about 60% of its approximately 500,000-customer electric base. As of 7 a.m. CT on Monday, August 24, NIPSCO reported 10,187 customers currently without power, roughly 4,302 of them still out from the August 11 storm and the events that followed. Cumulative outages logged since August 11 total approximately 374,500, with 364,400 restored. Full restoration for Gary and surrounding communities was projected for Tuesday, August 25 — fourteen days.
Commonwealth Edison (ComEd). Nearly 410,000 customers were affected across northern Illinois by the same August 11–12 system, with the heaviest damage in the south suburbs: Homewood, Flossmoor, Lansing, Chicago Heights, Mokena, Tinley Park, Joliet, Ford Heights, Glenwood and Lynwood. ComEd reported approximately 99% restoration by August 16 — five days — using more than 4,500 personnel, contractors and mutual-assistance crews including lineworkers from PECO, PHI and Ameren.
Both utilities faced comparable customer counts. The restoration timelines differed by more than a week.
Rebuild scale, not repair scale
Part of the gap is the nature of the damage. NIPSCO has been replacing thousands of poles and more than two million feet of wire. That is a system rebuild, not a repair operation — and rebuild work does not compress just because more crews arrive.
The other factor is that restoration curves are not monotonic. On Thursday, August 20 — nine days in — a downed line in Schererville knocked out an additional 9,000 customers, including traffic signals, in an area that had largely been restored. Facilities that had already transferred back to utility power went out a second time.
If your continuity plan treats restoration as a single event with a single end point, it does not describe what actually happened in Lake and Porter counties this month.
Context worth knowing
Indiana Gov. Mike Braun requested a federal major disaster declaration, with the state’s request estimating property damage above $5 billion. He mobilized the Indiana National Guard along with teams from Indiana State Police, the Department of Natural Resources and the Department of Correction. On August 22, ComEd dispatched more than 60 employees across state lines to assist NIPSCO crews.
Braun has publicly criticized NIPSCO’s pace of restoration. Separately, a class-action lawsuit has been filed alleging the utility inadequately performed vegetation management and pole and line inspections. NIPSCO disputes the allegations, stating its vegetation management program is overseen by the Indiana Utility Regulatory Commission and that its vegetation management spend has more than doubled since 2016. The utility also suspended disconnections for customers affected by the outage.
For planning purposes, the relevant fact is simply this: restoration duration is contested, variable, and outside your control. Two neighboring utilities with similar customer impact produced timelines that differed by nine days. Your standby plan is the only part of that equation you own.
Sizing for the restoration, not the outage
Most commercial standby installations are specified against an implicit assumption — that utility service returns within hours, or at worst overnight. That assumption held for ComEd customers. It failed for two weeks in parts of Lake County.
Three areas separate the facilities that stayed operational from the ones that didn’t.
1. Extended runtime and fuel logistics
A generator sized correctly for the load can still fail the mission if the fuel plan is sized for 24 hours.
Base fuel capacity. NFPA 110 requires Level 1 systems to carry on-site fuel for at least two hours of operation at full load, and many AHJs require more — commonly 24, 48, or 96 hours depending on occupancy classification. Understand that these are code minimums, not continuity targets. A 96-hour tank in a 14-day outage means eleven resupplies.
Resupply is the actual constraint. In a wide-area outage, diesel delivery competes against utility crews, hospitals, telecom, municipal fleets, and every other facility on the same allocation list. Fuel suppliers triage by contract. If you do not have a standing emergency fuel agreement with defined response times and a named priority tier, you are in an unranked queue during the exact week the queue is longest.
Retail fuel is not a fallback. Gas stations without power cannot pump. During this event, that constraint was regional, not local — driving further did not solve it.
Diesel degrades. Fuel that has sat in a tank for eighteen months is not the same fuel that went in. Microbial growth, water accumulation and oxidation all reduce reliability at the worst possible moment. Annual fuel polishing and testing is cheap relative to a failed start.
Fuel quality on resupply. Under emergency allocation, you may receive fuel from unfamiliar sources. Sample and log every delivery.
Natural gas is not automatically resilient. Gas service generally survived this event, but gas-fired units still depend on line pressure and on electrically powered control systems at the facility. Verify what happens to your gas train when the building is dark.
2. Rental and bridge power — decide before you need it
Facilities without permanent standby generation, or with units too small for full-building load, faced a rental market that tightened within hours of the storm.
Availability collapses regionally, not locally. A 500 kW rental unit in a 400,000-customer outage zone is competing against every other facility in that zone. By day two, the nearest available units may be several states away, and mobilization time becomes the binding constraint rather than price.
Pre-negotiate the terms you can’t negotiate under pressure. Response time commitments, priority tiering, rate structure for extended rental, mobilization and demobilization cost, and fuel included versus billed. Facilities negotiating these terms on day one of an outage negotiate badly.
Know your connection point. A rental generator is useless without a safe, code-compliant way to connect it. Facilities with pre-installed docking stations, camlock connections or manual transfer switches were online in hours. Facilities requiring an electrician to fabricate a connection under emergency conditions waited days — and paid emergency rates for the privilege.
Right-size the bridge. You may not need to carry full building load. Identify your critical circuits now — refrigeration, process controls, server rooms, life safety, security, sump and lift pumps — and know what kW that subset actually represents. A correctly specified 200 kW bridge that’s available beats a 750 kW unit that isn’t.
Sequence matters for multi-site operators. If you run several facilities in one utility territory, decide in advance which sites get the first available unit. Making that call in the moment costs hours you don’t have.
3. Post-event inspection and load bank testing
This applies to every facility whose generator ran during this event — including the ones that performed flawlessly.
A standby unit that ran continuously for 200+ hours has done something it was never designed to do routinely. Standby-rated generators are built for limited annual operation at variable load. Two weeks of continuous duty is prime-power service performed by standby-rated equipment.
What to inspect now:
- Oil and coolant analysis. Extended runtime accelerates wear. Fluid analysis identifies bearing wear, coolant intrusion and fuel dilution before they become failures.
- Air and fuel filtration. Service intervals are specified in hours, not months. A unit that ran two weeks may have consumed a full year of service life.
- Cooling system. Debris ingestion during and after a storm is common. Inspect radiators, verify coolant condition, check for airflow obstruction.
- Wet stacking. Units that ran extended hours at light load — common in facilities running only critical circuits — accumulate unburned fuel and carbon in the exhaust system. Left uncorrected, this degrades performance and shortens engine life. Load bank testing is the remedy and should be scheduled promptly.
- Battery and starting system. Repeated start attempts, and charging systems that were themselves without utility power, both stress batteries.
- Transfer switch inspection. Your ATS may have cycled multiple times — particularly in areas that experienced re-outages during restoration. Inspect contacts, verify timing settings and confirm operation under load.
- Alternator and windings. Insulation resistance testing after extended operation, especially in the high humidity that followed this event.
- Documentation. Log runtime hours, load profile, fuel consumed and any anomalies. This record supports both your maintenance program and your compliance file.
And for units that did not start, or started and failed: conduct a root-cause investigation, not just a repair. Under NFPA 110 and, for healthcare occupancies, NFPA 99, EPSS failures carry documentation and corrective-action obligations. Your AHJ may request that record.
The planning question this event actually asks
Not “do we have a generator?” — most of these facilities did.
The question is: what is the longest utility outage our operation can absorb, and does our standby plan actually cover that duration?
For most commercial and institutional facilities in the Midwest, the honest pre-August answer was somewhere between 24 and 72 hours. Northwest Indiana just demonstrated a 336-hour scenario in a mature, well-populated utility territory — not a remote one.
Get your standby fleet evaluated
Generator Source provides full-service standby power support for commercial, industrial, institutional and government facilities — including generator sales, preventive maintenance, repairs, load bank testing and fleet assessment.
If your equipment ran during the August 11 storms, it needs post-event service. If it didn’t run, or didn’t run long enough, it needs evaluation before the next event.