Land & Renewables Connection

Pennsylvania's new GRID Standards may push data center developers toward cleaner backup power, and battery energy storage systems (BESS) are emerging as a viable alternative to diesel generators. But a BESS is not a single technology, and the type proposed for a site may carry a very different risk profile. For the developers proposing these projects, the landowners living near them, and the municipalities reviewing them, that difference matters.

Data centers have become one of the most contested land use issues in Pennsylvania, and the concerns driving that opposition echo the same issues raised around the country. Data centers consume large amounts of energy and use significant amounts of fresh water. A common flashpoint for data center development is the sound and emissions that come from the diesel generators data centers use for backup power.

Data centers require reliable, uninterrupted power. That means redundant backup generation, which has often taken the form of large diesel generators. Virginia, the data center capital of the United States, has over 9,000 diesel generators, with more than 4,700 concentrated in Loudoun County alone.

Against that backdrop, on May 27, 2026, Pennsylvania Governor Josh Shapiro released the Governor’s Responsible Infrastructure Development (GRID) Standards. GRID certification requires developers to demonstrate compliance across four areas: protecting energy affordability (including a requirement that developers provide for their own energy needs without passing costs onto ratepayers), transparency and community engagement, workforce and economic development, and environmental protection. Certified developers gain access to the PA Permit Fast Track Program and eligibility for sales and use tax exemptions on data center equipment.

These GRID Standards are voluntary — a developer can build a data center in Pennsylvania without meeting them. But voluntary standards that condition tax benefits and permitting advantages on compliance are, in practice, a policy choice about how the Shapiro Administration wants data center development to proceed. With that focus on energy affordability and environmental protection, questions arise about the continued use of diesel generators, and their emissions, as back-up power sources in data center developments.

An alternative the GRID Standards may be pointing toward, and the alternative that data center developers are increasingly exploring to address noise and emissions concerns with diesel generators, is the battery energy storage system, or BESS. But, like most things, nothing is perfect, and a BESS is not necessarily the cure for every backup power concern at a data center.

What Is a Battery Energy Storage System (BESS)?

A battery energy storage system does what its name suggests: it stores electrical energy for later use. It is a battery. At a data center, a BESS can supply backup power like a diesel generator would, but its operational noise profile is much lower than a generator’s. There are also no exhaust emissions from a BESS during operation, and it has no fuel to store on site. Those characteristics can make a BESS more attractive than diesel generators across a spectrum of concerns, ranging from logistics, to impacts on neighboring properties, to broader environmental concerns.

For a developer trying to address community opposition centered on the impacts of diesel generators, BESS is an attractive alternative. Major technology companies have recognized this, announcing plans to eliminate diesel generators some data centers in favor of battery-based backup systems.

Energy storage is not a new concept for power generation. Reservoirs behind hydroelectric dams function as stores of energy, and pumped hydroelectric storage has worked as an energy storage mechanism for decades, using off-peak power to pump water uphill into a reservoir and generating electricity when it flows back down. The Seneca Pumped Storage Generating Station in Warren County, Pennsylvania has operated for over half a century. But whereas water reservoirs occupy large areas, a BESS offers the potential to store large amounts of electricity in a much smaller footprint. That advantage can come with a risk.

What Happened at the Moss Landing Battery Fire?

If you take a boat out into Monterey Bay, California, chances are — fog permitting — you can spot the massive smokestacks of the Moss Landing power station looming on the eastern shore. The site is home to one of the largest battery energy storage systems in the world. On January 16, 2025, a fire started in a 300-megawatt lithium-ion battery storage facility there containing approximately 100,000 battery modules. The fire burned for several days. More than half of those battery modules were damaged.

The cleanup was not a matter of weeks. Over a month after the fire started, crews began delinking the lithium-ion batteries from one another to prepare them for removal. That process did not conclude until March 2025. Physical removal of the batteries did not begin until September 29, 2025 — eight months after the fire. The cause remains under investigation.

This fire was so difficult to contain because of the chemistry of lithium-ion batteries — the same chemistry behind the rare but well-known cases of phones and laptops overheating and catching fire. Lithium-ion batteries can undergo thermal runaway, a chain reaction in which a failing cell generates heat that causes adjacent cells to fail, producing more heat and causing more failures. Once that process begins, it is extremely difficult to interrupt.

As the Moss Landing fire showed, a thermal runaway incident involving lithium-ion batteries at industrial scale presents large-scale safety issues: fires that burn for days, hazardous materials that can leach into soil and groundwater, and cleanup timelines measured in months. These are not theoretical risks. Moss Landing is a concrete example of what happens when things go wrong.

Not All Battery Storage Is the Same

For a data center’s backup power needs, battery energy storage is an upgrade over diesel generators in terms of noise and emissions. But the potential for a significant thermal runaway incident may offset some of that benefit for nearby residents and public safety officials. There is a trade-off — and a BESS is not a single technology. Lithium-ion is well suited for backup power because it is energy-dense, responds within milliseconds, and is supported by a mature supply chain. But it is not the only chemistry available, and the alternatives carry different risk profiles.

Iron-based batteries are one alternative to lithium-ion. Iron flow and iron-air system developers promote their use of non-toxic and non-flammable materials. Iron-based battery systems are not subject to the same type of thermal runaway that lithium-ion cells are, potentially avoiding a repeat of the Moss Landing fire. An iron-based system that fails would likely not produce the same kind of days-long, hard-to-extinguish fire that a large-scale lithium-ion thermal runaway can generate.

Iron-based systems come with their own trade-offs, however. They are generally less energy-dense than lithium-ion storage, requiring a larger physical footprint for the same capacity, and their efficiency is lower. They may also be better suited to a different application than fast-response backup. Iron-based chemistries are built for long-duration storage measured in many hours or days. A recently announced iron-air project in Minnesota — a 30 gigawatt-hour system paired with wind and solar — is designed to provide 100 hours of energy storage, not millisecond backup in case of a sudden failure of the power grid.

What This Means for Pennsylvania Zoning

This is where it gets difficult for developers, landowners, and municipalities. Data centers need backup power that is always available and activates quickly. Among the available options, the relevant distinction is not a simple “safe-versus-dangerous” label. Even if diesel generators are set aside in favor of a BESS, the type of BESS proposed for a given site carries real consequences — for fire risk, footprint, emergency response, and what the facility is actually capable of doing. Treating “battery storage” as a single, undifferentiated category obscures all of it.

That raises practical questions in the zoning realm. How granular should the regulation be? Should a zoning ordinance contemplating data centers dictate the type of backup power that will be used? Should it specifically address internal combustion generators or BESS installations? Should it distinguish between BESS chemistries, like lithium-ion and iron-based batteries? Should the permissible locations for a data center depend on the type of backup power it will use, and that source’s potential impact on the surrounding community? Or should battery storage be regulated generically, with chemistry left to the applicant?

The same questions run in the other direction for developers. A data center operator selecting a backup technology is making a decision with land use and permitting consequences, not only engineering ones. Defaulting to a lithium-ion BESS can address common community concerns about diesel generator noise and emissions, but it may invite more robust fire-prevention requirements, among other conditions, and stir community concern with fire danger. A data center operator that selects a BESS chemistry with a lower fire risk for back-up power could find a smoother path through local approval and fewer objections from neighbors. How granular a developer wants to be about chemistry is increasingly a question with legal and economic dimensions, not just technical ones.

None of this is an argument for or against any particular technology, or against battery storage generally. It is an argument for specificity. The GRID Standards point data center developers toward cleaner backup power, and they reflect a reasonable policy direction. But a state certification framework does not tell a municipality how to evaluate the difference between battery back-up systems, or between a battery facility and a bank of diesel generators.

A municipality that treats all backup power as interchangeable is not positioned to ask the right questions; a developer that treats the choice as a purely engineering decision is not accounting for the land use consequences that follow from it and neighbor concerns; and a landowner who lives near a proposed site has every reason to ask what, exactly, is going to be built next door. That evaluation still has to happen at the local level, and it is better for all parties if it is done before an application arrives, the hearing process begins, and everyone begins to recognize that there is too much ambiguity in the data enter land use and development framework.

If you have questions about BESS, data center zoning, or related land use matters in Pennsylvania, see our Renewable Energy, Zoning and Land Use practice page and contact Brendan A. O’Donnell at odonnellba@hh-law.com or 412-288-2226.