Baltimore Grid Emergency: How PJM Avoided a Major Blackout

On August 11, 2025, the Baltimore area came close to a major blackout. A cascade of equipment failures at the Brandon Shores substation put about 1,200 MW of electricity load at risk, enough to power roughly 1 million homes.

Instead, grid operator PJM Interconnection and Baltimore Gas and Electric contained the event to a brief outage for about 4,000 customers.

Here is what happened, how PJM and BGE limited the damage, and why demand response was one of the most important tools they had.

What Happened at Brandon Shores on August 11?

Equipment failures began at the Brandon Shores 230 kV substation near Baltimore around 3:30 a.m. on August 11, 2025, during heavy fog, and the entire substation was lost by about 7:30 a.m., according to PJM.

As demand climbed through the hot afternoon, PJM and BGE ran emergency reliability studies. They showed the local grid was in serious danger.

Without action, the failure could have cascaded into the loss of about 1,200 MW of load, affecting roughly 1 million homes, according to PJM.

How Did PJM and BGE Prevent a Wider Blackout?

PJM and BGE used demand response, voltage reduction, and a small, targeted load shed to keep the event from cascading, according to PJM.

The actions, in order:

• ●Demand response. Customer load management programs cut about 230 MW of demand.
• ●Voltage reduction and load curtailment. Another 60 MW of relief between 2 and 5:15 p.m.
• ●Targeted load shed. A 20 MW load shed directive, issued at 3:52 p.m. and ended by 4:20 p.m.

The result: about 4,000 customers in Howard County lost power for roughly 28 to 30 minutes. What could have been a days-long blackout became a short, controlled event.

Kevin Hatch, PJM's senior manager of dispatch, said: "In close coordination with BGE, we did everything we could to limit the risk to load."

What Is a Load Shed, and Why Is It a Last Resort?

A load shed is a controlled, temporary power cut to a small group of customers, ordered by grid operators to protect the rest of the system from a larger, uncontrolled failure.

When demand exceeds what the grid can safely deliver, equipment can overload and trip offline. That can set off a chain reaction that takes down a much larger area.

Cutting a small amount of load on purpose prevents that cascade. But it means some customers lose power, so operators use every other tool first.

In Baltimore, that meant demand response and voltage reduction came before any load shed. By the time operators issued the load shed directive, they needed only 20 MW, a tiny fraction of the 1,200 MW that had been at risk.

Why Was Demand Response So Important?

Demand response provided the largest single block of relief, about 230 MW, by paying large customers to reduce usage when the grid needed it.

Demand response works because it can act fast. Instead of starting a power plant, grid operators ask customers who have agreed in advance to cut use.

It's one of the cheapest and fastest reliability tools a grid has. Data centers and other large loads can play the same role, as we covered in how data centers could become grid assets.

Baltimore avoided a disaster because of preparation, not luck.

What Made the Response Work?

PJM says the response drew on lessons from the 2003 Northeast and 2011 Southwest blackouts, regular drills, and ongoing operator training.

According to PJM:

• ●Blackout lessons. Procedures shaped by studies of past major outages.
• ●Regular drills. Voltage reduction drills with transmission owners twice a year.
• ●Operator training. Scenarios based on analysis of real events.
• ●Coordination. Close communication between PJM, BGE, and local officials.

That preparation meant operators could act quickly and in the right order as conditions worsened.

Why Does This Event Matter Beyond Baltimore?

The Baltimore event shows how a single equipment failure can threaten a large area when the grid is already stretched.

PJM faces rising demand and tight supply. We've covered how PJM is struggling to meet demand from AI and how aging equipment and long transformer lead times strain the system.

When margins are thin, the tools that can respond in minutes matter most.

What Other Tools Help Keep the Grid Reliable?

Distributed resources like rooftop solar, batteries, and virtual power plants can reduce peak demand and support the grid during emergencies.

Examples we've covered:

• ●New England. Rooftop solar cut the region's peak by more than 2,000 MW during a June 2025 heat wave.
• ●Puerto Rico. A virtual power plant of about 70,000 home batteries helped prevent load shedding.
• ●Michigan. Lawmakers are advancing statewide virtual power plant programs.

As demand grows and extreme weather stresses the grid, these tools become essential, not optional.

What Does This Mean for Solar Owners?

Solar systems that are working, especially when paired with storage, reduce demand on the grid during the hottest hours and can support reliability programs.

But that only counts if the system is producing. Many commercial systems installed in the 2010s are losing output to aging inverters or degraded panels. Repowering an aging PV system can restore that output.

Start With a Ballpark Estimate

If you own an existing commercial solar system, find out what your existing solar project may be worth before deciding whether to repair, repower, or sell.

Source: PJM Inside Lines, "PJM Details Its Actions To Minimize Aug. 11 Baltimore Load Shed Event"