Quick quiz: what do you pay for electricity? If you just thought of a number in cents per kilowatt-hour, you gave the answer most business owners give. And it's incomplete. That number is your supply rate — the cost of actual electrons. But in deregulated markets, there's a whole other line item quietly eating 20-30% of your electric bill, and most businesses have no idea it exists. It's called the capacity charge, and we need to talk about it.

What Capacity Charges Are

The grid has to keep enough power plants online to handle demand at all times — including the absolute peak. Building and maintaining those plants costs money whether they're running or sitting idle. Capacity markets are how grid operators make sure the lights stay on.

Think of it as insurance. You're paying a premium so that when everyone in your city cranks their AC during a 100-degree heat wave, the grid doesn't collapse. That premium is your capacity charge, and it's divided up based on how much you contributed to peak demand. Use a lot during the worst hours? You pay more. It's that simple — and that consequential.

Every major grid operator handles this differently, which is part of why it's confusing:

• PJM (PA, OH, NJ, MD, IL-north, VA, DE, DC): Runs the Reliability Pricing Model (RPM), auctioning capacity three years ahead. Your cost is based on your Peak Load Contribution (PLC) — your demand during the five highest system peak hours. Remember that number.
• ISO-NE (MA, CT, NH, ME, RI, VT): Runs the Forward Capacity Market (FCM), also three years ahead, with a Pay-for-Performance twist that punishes generators who underdeliver during crunch time.
• NYISO (New York): Runs an Installed Capacity (ICAP) market with monthly, seasonal, and annual auctions. If you're in NYC or Long Island, brace yourself — you're paying dramatically more than upstate.
• MISO (IL-south, MI): Runs a Planning Resource Auction (PRA) with seasonal obligations. Historically cheaper, but costs are climbing fast as coal plants disappear.
• ERCOT (Texas): No capacity market at all. Generators get paid only through the energy market. Which is exactly why ERCOT prices can go from normal to insane in the span of an afternoon.

How Capacity Costs Are Allocated to Your Business

Let's focus on PJM, since it covers the most deregulated states. Your capacity obligation comes down to your Peak Load Contribution (PLC) — what your meter read during PJM's five highest system peak hours. Those hours almost always land on the hottest summer afternoons, June through September.

Here's the part that should make you sit up: your capacity costs for the entire next year are set by what you used during five specific hours this summer. Five hours. That's it. Reduce your consumption during those hours and your capacity obligation — and your capacity bill — drops for the following twelve months.

Let me put numbers on this. Say your facility normally pulls 500 kW on summer afternoons. If you can cut to 350 kW during the five coincident peaks, your PLC drops 30%. At capacity prices of $8-12/kW-month (typical in PJM's eastern zones), that 150 kW reduction saves you $14,000-$22,000 per year. From five hours of effort. I don't know about you, but that's a return on attention I'd take any day.

Why Capacity Costs Are Rising

This isn't getting better anytime soon. Here's what's pushing costs up:

• Generator retirements: Coal plants and older gas plants are closing faster than anyone's building replacements. Fewer resources bidding in capacity auctions means higher clearing prices. Supply and demand — it works in electricity too.
• Renewable intermittency: Wind and solar get reduced capacity credits because they can't guarantee output when you need it most. As they replace conventional generators, the remaining dispatchable plants become more valuable — and more expensive.
• Electrification everywhere: EVs, heat pumps, data centers — all adding peak demand. More mouths at the table, same amount of food. You can guess what happens to prices.
• Transmission bottlenecks: Can't move power from where it's cheap to where it's needed? You get localized capacity premiums. NYISO Zone J and PJM's eastern zones are poster children for this problem.

Strategies to Reduce Your Capacity Costs

1. Peak Demand Management

This is the highest-return move: just use less during the hours that set your PLC. You need to know when those peak hours are likely to hit (hot summer weekday afternoons — not exactly unpredictable) and have a plan ready to shed non-critical load.

Pre-cool the building before peak hours. Shift manufacturing runs earlier or later. Dim the lights nobody notices anyway. Fire up backup generators to take load off the grid. None of this is glamorous, but it's effective.

2. Demand Response Programs

Every major grid operator pays businesses to cut load during emergencies. Read that again: they pay you to reduce costs you'd otherwise be stuck with. It's one of the rare win-wins in energy markets.

PJM's Economic and Emergency Demand Response, ISO-NE's On-Peak and Seasonal-Peak programs, NYISO's ICAP Special Case Resource — they all pay meaningful money if you can curtail 100+ kW when called upon. If you're not enrolled and you're eligible, that's money you're leaving on the ground.

3. Battery Storage

On-site batteries can discharge during exactly the peak hours that determine your capacity obligation. The economics have gotten dramatically better as lithium-ion prices have dropped, and in high-capacity-cost zones, the capacity savings alone can justify the investment. You don't even need to factor in the other benefits — the math works on capacity alone.

4. Contract Structure Awareness

Here's something that drives me a little crazy: some supply contracts bundle capacity into an all-in rate. You can't see it, you can't manage it, and you have zero incentive to reduce it. Other contracts pass capacity through separately at actual cost, which gives you full visibility and a reason to care about your PLC. If your contract hides capacity, you should probably ask why.

The Bottom Line

Capacity charges are real, they're big, and they're heading in one direction. If you're a commercial business in PJM, ISO-NE, or NYISO territory and you're ignoring capacity costs, you're essentially volunteering to overpay. The businesses that come out ahead are the ones that treat capacity as something they can actually control — not as some immovable line item on the bill. Five hours of summer management can save you five figures per year. That's the kind of math everyone should care about.