The Grid Held. Your Lights Might Not Have.

Five utilities, one heat dome, and the voltage story SAIDI and SAIFI don't measure

Source: ConEd

During the week PJM pushed toward an all-time peak, interconnection frequency spent most of its time running slightly high — a sign, as covered here last week, that the system had real-power balance well in hand even as it leaned hard on reactive support. Zoom out to the interconnection level and the story is almost boring: the grid held.

Zoom into any individual utility’s distribution system that same week, and “the grid held” stops being the whole story. Con Edison cut voltage across four boroughs and into Westchester County, then cut power outright to nearly 10,000 customers in Queens for a completely different reason. Baltimore Gas & Electric ran emergency load-cycling events while cable faults tripled. Commonwealth Edison — running some of the most sophisticated voltage-optimization software in the country — still posted the worst voltage numbers on the entire Whisker Labs/Ting network. And in Lakewood, Ohio, thousands of FirstEnergy customers lost power for days, for a reason the utility and its regulator both already knew about before the heat wave started.

Five utilities, one heat event, four genuinely different failure mechanisms. None of them shows up the same way in the numbers utilities are required to report — and one of the biggest doesn’t show up in a formal metric at all.

Two Different Numbers

If last week’s note left you thinking about frequency, it’s worth pausing on why frequency and voltage aren’t the same failure mode, because the two get conflated constantly.

Frequency is a system-wide number — one value, shared essentially instantaneously across the entire synchronous interconnection, telling you whether generation and load are in balance right now. When PJM’s frequency ran high through the emergency, that wasn’t relief; it was the reactive side straining while the real-power balance held.

Voltage is a local condition. It decays with distance, current, and impedance, and it’s set by conditions at a specific point on a specific feeder. A system can sit dead-on 60.000 Hz across the entire interconnection while individual customers three miles down an overloaded feeder are looking at 108 volts at the wall outlet. That’s the story this piece is about — the big number stayed fine. The local number didn’t, and across the five utilities below, it didn’t fail the same way twice.

Con Edison: One Utility, Two Failures

Con Edison did two distinct things this heat wave, and conflating them costs you the actual story.

The first was a decision. Beginning July 2, ConEd cut voltage 8% across northern Manhattan, the northwest Bronx, Queens, Staten Island, and Westchester — a conservation voltage reduction: precautionary, reversible, and the same move it made in June 2025 under similar conditions. It’s a deliberate operational lever — lower the voltage a controlled amount, shave demand across the system, buy margin. Some Richmond Hill and Forest Hills residents reported it felt closer to 20–25% than the announced 8%, a gap worth taking seriously — but that’s a measurement dispute about a chosen action, not evidence of a different mechanism.

The second was not a decision. On July 3, ConEd cut power outright to roughly 9,800 customers across Howard Beach, Ozone Park, Richmond Hill, and South Ozone Park, plus a separate outage in Riverdale. ConEd’s own statement is specific: temporary shutoffs due to equipment problems caused by extreme heat and heavy demand, done to allow faster repairs and head off longer, wider outages. That’s equipment reaching a thermal or capacity limit it wasn’t rated to handle and failing — the same physics that shows up next at BGE.

Neither of these is new for ConEd, and neither is likely to be the last. NYISO has warned of possible NYC-area blackouts as early as this summer, and ConEd’s own reliability modeling shows a projected reliability margin of negative 1,679 MW under a sustained three-day, 95°F event — close to the event that just happened. That number sits in the background of ConEd’s ongoing rate case friction with Governor Hochul’s office, an 11.4% electric rate request currently drawing an audit demand.

BGE: The Same Failure, a Different Territory

Baltimore Gas & Electric spent July 1–2 running emergency cycling events while its cable faults climbed from roughly 1,400 to more than 3,000 affected customers. That’s not a coincidence of timing with ConEd’s shutoffs — it’s the same underlying mechanism showing up somewhere else. Two separate utilities, two separate service territories, the same failure mode in the same week: equipment that runs fine most of the year hitting a thermal limit under the combined stress of extreme heat and heavy demand. One data point is an anecdote. Two independent utilities failing the same way in the same event is a mechanism.

ComEd: When Good Software Meets a Bad Substation

Commonwealth Edison is, on paper, the utility doing this the right way. It runs a regulator-mandated closed-loop voltage optimization system — Aspen VVC/VVO, built around a Distribution State Estimator that fuses SCADA, AMI, and sensor data with a network model to estimate voltage at every node on a feeder, then optimizes tap changers, capacitor banks, and regulators against that modeled profile in real time. That’s a fundamentally more sophisticated approach than the fixed-percentage tap cut ConEd runs — no blind spot past the substation, an actual model of where the worst voltage on the feeder is likely sitting.

And ComEd still topped the entire Whisker Labs/Ting network for the worst voltage performance during this event.

Whisker Labs Map from the 2025 Heat Dome, Source: Whisker Labs

The reason isn’t the software. It’s what the software is fighting. A meaningful share of ComEd’s substations and feeders date to the late 1960s and 1970s, running over their original design capacity, and no control algorithm creates physical headroom that doesn’t exist. ComEd’s own $15.3 billion capital rebuild plan doesn’t finish until 2028–2031. Until then, the closed-loop system is doing genuinely good work holding the line as gracefully as physics allows — it’s just holding a line that’s already too close to the edge.

There’s a regulatory wrinkle worth flagging here too. The Illinois Commerce Commission’s own Performance Metrics 2.0 workshop, in April 2025, confirmed ComEd tracks no formal power quality metric at all — momentary interruptions, voltage sags and swells go essentially unmeasured, even as SAIDI, SAIFI, and CAIDI keep ComEd in the “first decile” nationally in its own filings. ComEd’s 2022 “System Visibility Index” proposal reads, in hindsight, like a tacit admission of the same gap. The metrics that make it into a rate case filing are the metrics that don’t capture this problem at all. (This event’s separate 297,000-customer outage count was storm-compounded — a different, unrelated story, not part of the voltage picture above.)

FirstEnergy: The Failure Everyone Already Saw Coming

Lakewood, Ohio, isn’t a case of adequate equipment meeting an unprecedented extreme. It’s the opposite — a known, specifically identified failure point that simply hadn’t been fixed yet when the heat wave arrived.

Underground lines feeding the Lauderdale substation failed on Lakewood’s southwest side, leaving roughly 1,200 customers without power for multiple days in triple-digit heat-index conditions. FirstEnergy’s public statement attributed the strain to the heat wave driving elevated regional demand. Lakewood Mayor Meghan George’s account, filed as an updated complaint with the Public Utilities Commission of Ohio (PUCO), is considerably less forgiving: this is the same playbook as a 2025 outage event that triggered a formal PUCO probable-noncompliance finding — a finding that explicitly stated the earlier failures were “caused by equipment or line failure,” not weather, and that FirstEnergy’s infrastructure serving Lakewood was “older than infrastructure found elsewhere.” PUCO’s own October 2025 corrective-action letter didn’t specifically address the Lauderdale substation — which is exactly why Mayor George is now asking PUCO to reopen the case and add a financial-penalty component: fines, ratepayer refunds, or an escrow mechanism.

The timing sharpens the point. PUCO denied FirstEnergy’s request to loosen its own reliability standards on June 23 — nine days before this outage began. Whatever else is true about this event, “we didn’t see it coming” isn’t an available explanation for anyone involved — not the utility, and not the regulator.

A Cleveland Footnote

Lakewood sits entirely outside Cleveland city limits and entirely within FirstEnergy’s Illuminating Company territory — worth stating plainly, because it’s tempting to fold this in with Cleveland Public Power’s own troubles (a battery fire at CPP’s Lake Road substation last June left 3,000-plus customers dark for about 18 hours) into a single Cleveland story. Don’t. They’re genuinely separate failures with genuinely opposite root causes: FirstEnergy’s is deferred capital investment by an investor-owned utility that can raise rates and chose not to spend fast enough; CPP’s is four decades of frozen municipal rates that left a public utility unable to fund capital replacement at all. Regular readers know that story — it’s the subject of “Forty Years of Free.”

The two utilities are connected, just not in a way that makes one utility’s transformer the other’s problem. CPP’s own filings state that it obtains substantially all its power through agreements delivered via CEI interconnections — a dependency that traces back through Centerior to at least the 1990s. A public utility founded in 1906 explicitly to compete with the private one still needs the private one’s wires to get most of its power to market. That’s not a shared distribution asset, and it doesn’t merge the two outage stories into one cause — but it’s a fitting irony for a city with two utilities failing independently, for opposite financial reasons, in the same week.

SCE: The One That Doesn’t Fit the Pattern

Southern California Edison is worth naming precisely because it breaks the pattern instead of confirming it. SCE’s voltage and reliability decisions this time of year are driven overwhelmingly by wildfire risk — Public Safety Power Shutoffs, de-energization ahead of red-flag conditions — not by thermal capacity limits on aging equipment. It’s a genuinely different risk calculus, running on a genuinely different trigger, and folding it into the same bucket as the other four utilities would blur a distinction worth keeping sharp: not every utility having a bad week this summer is having the same bad week.

What the Big Number Doesn’t Tell You

Put the interconnection frequency chart from last night’s note next to any of these five distribution stories and you’d never guess they happened the same week. That’s not a contradiction — it’s the entire point. “The grid held” is a true statement about generation and load balance across an entire synchronous interconnection. It says nothing about whether your specific feeder, your specific substation, or your specific transformer held too.

Most of what determines that answer for you personally isn’t in a filing anywhere. SAIDI (System Average Interruption Duration Index)and SAIFI (System Average Interruption Frequency Index) track sustained outages. They don’t track ComEd’s brownouts, because nobody requires ComEd to measure them. They don’t distinguish ConEd’s deliberate 8% cut from ConEd’s equipment failure three days later, because both just look like “ConEd had a bad week” from the outside. And they say nothing at all about whether the fix for your neighborhood’s specific failure point has actually been funded, or just promised.

If you want to know which of these five stories is happening to you, the honest answer this summer is: check your own outlet. My own plug-in Ting sensor — the same Whisker Labs network cited throughout this piece — told me more about my service quality this month than any regulatory filing did. Thanks for reading, please share your outage story.