Can Battery Storage Fix PJM’s Power Crunch?

A battery can help during a shortage, but it cannot make electricity from nothing

Grid batteries are attracting big utility plans as the PJM power market faces tighter supply. The appeal is easy to grasp: charge when electricity is available, then send it back when demand rises. The harder question is whether batteries can reliably cover the hours when the grid needs them most.

The answer depends on more than how many batteries a company announces. Storage has a limited number of hours, must be connected where the grid can use it, and needs a reliable way to charge. Those constraints help explain why battery investment can ease a power crunch without ending it.

Recent reporting by Utility Dive on Exelon’s interest in major storage investment brings that question into focus. The headline signals that utilities see storage as part of the response to PJM’s supply concerns. It does not, by itself, tell us how much usable capacity will reach the grid, or when.

Fact: PJM needs dependable power at specific times

PJM Interconnection coordinates the high-voltage grid and wholesale electricity markets across all or parts of 13 states and the District of Columbia. The grid operator serves about 67 million people. Its job is to keep supply and demand balanced across that large system, not simply to count how many power plants or batteries exist.

One measure of future supply is PJM’s capacity auction. In its 2025 auction for the 2026–27 delivery year, the clearing price reached $269.92 per megawatt-day, the auction’s price cap. That result was a signal of tight capacity conditions. It was not a prediction that every customer’s bill would rise by a matching amount, nor proof that a particular technology could solve the shortage.

Capacity and energy are related but different. Capacity is the ability to provide power when called upon; energy is the electricity delivered over time. A battery rated at 100 megawatts can discharge at that rate, but a four-hour system can sustain it for only four hours before it needs to recharge.

The U.S. Department of Energy describes storage as a way to shift electricity across time and support grid operation. That is useful when the grid has surplus power at one time and needs it later. Storage does not create additional energy: losses during charging and discharging mean the system returns less electricity than it took in.

Interpretation: duration and location decide the value

For a battery, the difference between power and duration is not a technical footnote. A 100-megawatt, four-hour battery stores 400 megawatt-hours. It can be powerful during an evening peak, but it cannot replace a generator that runs through a long, cold spell or a multi-day stretch of weak renewable output.

That makes storage a strong fit for short, predictable gaps. It can absorb solar output during sunny hours and release some of it after sunset. It can also respond quickly when demand jumps or a generator trips. For those services, a battery can be valuable even if it supplies only a modest share of the region’s total annual electricity.

Location matters just as much. Electricity moves through a physical network with limits, and a battery on one side of a congested transmission line may not solve a shortage on the other. A project needs an interconnection, equipment, permits, and a place in the grid where its output can reach the customers who need it. A headline number for planned investment skips these practical steps.

This is why storage proposals often draw arguments about siting and local impacts, not just engineering. Greadly’s coverage of pushback over a proposed battery project in Kenosha County shows how a regional grid need can meet local concerns about a specific site. A grid benefit does not automatically settle questions about land use, safety, or who bears the project’s burdens.

Storage also works best as part of a portfolio. Transmission upgrades can move power between regions; demand response can reduce consumption at peak times; generation can provide longer-duration supply. Batteries complement those tools rather than making them obsolete. As our guide to energy storage and the grid explains, the grid’s needs vary by hour, location, and duration.

What a large investment plan would need to prove

To judge an announced storage program, look for details that connect the spending to grid service. How many megawatts and megawatt-hours are planned? What duration will the systems provide? Which projects have interconnection approval, and what are their expected in-service dates? Are they intended for local reliability, wholesale-market sales, renewable integration, or several uses?

The charging plan deserves equal scrutiny. A battery charged during a period of surplus low-carbon power can help shift that electricity into a more useful hour. A battery charged from a grid dominated by fossil generation may still provide flexibility, but its climate benefit depends on when it charges and what generation it displaces when discharging. “Battery” is a description of equipment, not a complete account of its effects.

For customers, the path from utility investment to a bill is also indirect. Market rules, project costs, regulatory approvals, and the timing of construction all matter. A storage project might help reduce scarcity or improve reliability, but those possible benefits do not guarantee a lower bill. The connection between a megawatt-hour stored and a household charge is not a straight line.

Prediction: batteries will help most at the edges of the shortage

Over the next several years, expect storage to become a more common part of utility planning, especially where batteries can meet a short evening peak or ease a local constraint. That expectation rests on how the technology operates, not on a guarantee that any single investment plan will be built on schedule.

But if PJM faces a shortage lasting longer than a battery’s discharge window, storage alone will not fill the gap. Utilities and regulators will still need to secure enough generation, transmission, and demand flexibility for the difficult hours. A battery is a useful reserve of time. It is not an extra power plant that runs indefinitely, despite the promotional materials’ best efforts.

The useful question about a proposed storage buildout is therefore not whether batteries can fix PJM. It is which shortage hours the projects can cover, where they can deliver power, and what other resources will cover the rest. That is a less dramatic test than a multibillion-dollar headline, and a better one for judging whether the grid gets more dependable.