Battery systems store lots of potential for New York City. Here’s how they work.

In Chinatown, a six-story town­house quietly made history last year when it became the first multi-dwelling resi­den­tial building in New York City to install a battery energy storage system (BESS) for its own use. 

Installed by Brooklyn SolarWorks, the rooftop battery can charge off the solar array looming above it, reducing the amount of power the building draws (and pays for) from Con Edison’s grid. It’s big enough to power lights, appli­ances, and other essen­tial equip­ment for a few hours in the event of a blackout, Brooklyn SolarWorks founder and CEO T.R. Ludwig told Habitat maga­zine. 

That’s the good news. The bad news is that it took nearly eight years for the city to permit the battery following a marathon effort by Brooklyn SolarWorks and Briggs & Stratton, the system’s manu­fac­turer. It’s still the only resi­den­tial-scale energy storage system approved by the FDNY, according to Briggs & Stratton. And it’s quite small: About a quarter the size of the mobility battery used in a Tesla Model 3 sedan.

“The FDNY has made it next to impos­sible for the [New York City Department of Buildings] to approve anything, because they have limited what prod­ucts can even be used,” Dean Santa, exec­u­tive officer of Brooklyn-based solar installer Solanta, told Skylight in an email.

Energy storage has the poten­tial to play a large role in new infra­struc­ture as part of New York’s clean energy future. Properly-managed batteries can soak up cheap, low-emis­sions power and then discharge power when demand for elec­tricity spikes, replacing aging, expen­sive ​“peaker” plants that run on oil or natural gas.

But large-scale adop­tion is far from a fore­gone conclu­sion. Municipal red tape is one of several imped­i­ments to building out the decen­tral­ized energy storage networks in New York, which experts say will be neces­sary to meet city and state decar­boniza­tion goals. 

Adding to tensions are the social, struc­tural, and economic hurdles to over­come: Viral videos of scooters and e‑bikes bursting into flames fuel push­back from building resi­dents and neigh­bors; older build­ings may need costly retro­fits to meet venti­la­tion and fire suppres­sion codes for indoor systems or support rooftop systems’ weight; and Con Edison says parts of its elec­tric grid are already under too much stress to handle larger battery instal­la­tions without signif­i­cant, and expen­sive, upgrades.

Despite these hurdles, energy storage advo­cates say grid-tied batteries have too many bene­fits to ignore. They’re cautiously opti­mistic that New York will soon see more batteries in base­ments, rooftops, and lots around the city.

What is battery energy storage?

Today, most stationary energy storage batteries consist of lithium-ion. It’s the same basic chem­istry found in the smaller cells powering your laptop, phone, or e‑bike. 

In build­ings, batteries can be ​“stand­alone” or connected to a rooftop solar array in a ​“hybrid” config­u­ra­tion. Standalone batteries must draw power from the elec­tric grid, while hybrid batteries can charge directly off panels when the sun is shining. They’re typi­cally placed in building base­ments, garages, or on roofs.

Residential batteries store power until it’s needed, then discharge it back into the broader elec­trical grid, or for use locally within the building itself. Most instal­la­tions can discharge at full power for one to four hours before needing to charge again. Batteries used primarily for backup power may be config­ured to discharge at slower speeds.

Depending on the make and model, the energy storage capacity of a stationary battery can range from a few kilo­watt-hours (kWh) — a handful of e‑bike batteries, give or take — to well over a megawatt-hour (MWh). Large-scale instal­la­tions in rural or indus­trial areas can knit together dozens of indi­vidual batteries to reach hundreds of megawatt-hours at a single site. 

Brooklyn SolarWorks’s Chinatown instal­la­tion is petite by compar­ison at 19.6 kWh, the smallest FDNY-approved stationary battery. But larger New York resi­den­tial build­ings could in theory host megawatt-scale projects. Larger battery instal­la­tions are sprouting up at apart­ment commu­ni­ties in other major metro areas of the United States, like these two near Dallas which will serve a combined 531 housing units.

Potential benefits for buildings, the grid, and the environment

What bene­fits do on-site battery energy storage systems offer to building owners and residents?

Resilience, for one. With proper sizing and manage­ment, batteries can provide hours to days of backup power for lighting, kitchen appli­ances, and more. New York’s power grid is among the country’s most reli­able, but outages still occur and they often coin­cide with danger­ously hot or cold weather conditions.

Another poten­tial benefit: When paired with solar panels, or programmed to charge when the elec­tric grid is awash in carbon-free elec­trons from renew­able or nuclear power, batteries can help reduce host build­ings’ carbon inten­sity. (Batteries aren’t inher­ently climate-friendly, however. Charging when the local power mix is dirtier may indi­rectly increase carbon emis­sions or even over­load parts of the power grid.)

“If they all charge and discharge at the same time, that’s a chal­lenge [for the grid]. It’s no more helpful than anything else would be,” Alliance for Clean Energy New York’s exec­u­tive director Marguerite Wells told Skylight. ​“Running in series, when the grid actu­ally needs it — that is the job that we all believe batteries should be doing.”

Buildings metered on a Con Edison time-of-use rate, mean­while, can directly reduce net peak power consump­tion — and thus total energy costs — by charging batteries during cheaper off-peak periods and discharging when peak rates are in effect. 

Other customers stand to benefit, too. Powering enough energy-inten­sive appli­ances with batteries at peak demand lowers the risk of disrup­tive brownouts and black­outs, and reduces the need for high-emis­sions peaker plants. Some New Yorkers have already started to see these bene­fits: Last summer, the tech startup Every Electric part­nered with Con Edison to trial in-home battery packs to power air condi­tioners in 65 house­holds. The results were promising, where the batteries helped reduce strain on the grid, and users earned money just for using them.

Barriers to battery energy storage in NYC buildings

Many ​“commu­nity-scale” battery energy storage facil­i­ties already operate across the five boroughs and projects totaling at least 50 megawatts — enough to power tens of thou­sands of homes — are under devel­op­ment, according to Cleanview, which tracks energy devel­op­ment across the U.S. 

Community-scale energy storage is typi­cally sized between a few hundred kilo­watts and a few megawatts per site. The batteries often sit at ground level in nonres­i­den­tial areas, where fire is less likely to spread to surrounding build­ings. They’re also housed in sophis­ti­cated containers that meet FDNY’s rigorous safety stan­dards, said Paul Rogers, a retired FDNY lieu­tenant who helped develop the department’s energy storage safety codes. Advocates say higher adop­tion is the result of a thoughtful city-led plan­ning process.

“For a time, New York City was one of the hardest places in the country to get energy storage systems permitted,” said Wells of Alliance for Clean Energy New York. ​“Then, about half a dozen years ago, we got really good codes and a good [permit­ting] process. All of the sudden, it became pretty much the easiest place in the country…as long as you know what you’re doing.”

Barriers remain, however. Last fall, Con Edison proposed a new inter­con­nec­tion frame­work for larger battery systems that would require project devel­opers to pay for any grid upgrades it deemed neces­sary to avoid over­loading its infra­struc­ture. Developers and their allies said the frame­work could cost tens of millions per project and render many uneco­nomic. In March, the New York Battery and Energy Storage Technology Consortium said devel­opers had already canceled 25 projects and more than 90 others were at risk.

In a state­ment provided to Skylight, a Con Edison spokesperson said the utility ​“has been a cham­pion of battery storage” and touted its work with FDNY on the city’s safety codes. Batteries installed in the right loca­tions and ​“oper­ated during the right charging and dispatch windows” can reduce stress on the grid, they said.

But ​“because grid constraints vary across our system — from neighborhood‑level distri­b­u­tion lines to major trans­mis­sion corri­dors — the loca­tion of a battery ulti­mately deter­mines how much benefit it can deliver to the grid and to customers,” they added.

Though small-scale resi­den­tial energy storage systems may have an easier time connecting to Con Edison’s grid, code compli­ance can be costly, said Rogers, who now co-owns Energy Safety Response Group, a consulting firm that works with battery devel­opers, local offi­cials, and prop­erty owners to site and support energy storage facilities. 

To get a FDNY Certificate of Approval for an energy storage system, the manu­fac­turer needs to supply a detailed hazard miti­ga­tion analysis, emer­gency response plan, and results from ​“destruc­tive testing” by a nation­ally recog­nized lab, Rogers said. If a system is proposed to be placed in a base­ment or on a rooftop, Rogers said FDNY may add require­ments beyond what’s in the energy storage section of the city fire code, such as rein­forcing slabs for roof-mounted systems or extra sprin­kler capacity in rooms housing batteries.

It’s an expen­sive, painstaking process that’s never­the­less worth it for the large-scale battery systems used by commer­cial energy devel­opers around the city. But the benefit isn’t as clear for manu­fac­turers of the smaller batteries more likely to be used in resi­den­tial build­ings, Rogers said.

This may account for how few resi­den­tial systems have been deployed to date. Though New York City has more inhab­i­tants than most states, its resi­den­tial energy storage market may not be big enough to justify the addi­tional work, Rogers said.

“It’s not that FDNY is preventing them. It’s just that there are not a lot of prod­ucts that have gone through the process,” he said, adding that he can’t speak to indi­vidual manu­fac­turers’ thinking.

Though Rogers is an adept navi­gator of munic­ipal energy storage permit­ting — in an email, one commer­cial devel­oper called him ​“sort of the Jedi Master on [battery energy storage] issues” — he said it’s not always prac­tical to retrofit older resi­den­tial build­ings for indoor battery systems. A few years ago, concerns about whether a nearly 100-year-old host building could support the added weight derailed a Brooklyn project that would have been the first resi­den­tial rooftop battery system in the U.S. Adding new venti­la­tion shafts, sprin­kler lines and drainage can be prohib­i­tively expen­sive, too, Rogers said.

Property owners can recoup some energy storage instal­la­tion costs through New York City’s generous Solar and Electric Storage System Property Tax Abatement, which offsets 30 percent of system instal­la­tion costs up to $250,000. The city expanded the scheme in 2024 to allow owners who’d previ­ously claimed the abate­ment on solar systems to receive a sepa­rate credit for newly installed energy storage systems.

A sepa­rate state program offers a $250/​kWh incen­tive for eligible resi­den­tial energy storage systems in Con Edison’s terri­tory, which covers the five boroughs. That’s nearly $5,000 for a system the size of the one in Chinatown. 

Challenges notwith­standing, clean energy devel­opers see oppor­tu­ni­ties ahead for resi­den­tial energy storage in the city. Solanta’s Dean Santa said he’s getting homes ready for energy storage tomorrow despite a dearth of city-approved options today.

“We are circling the issue from a different direc­tion by preparing homes with all of the hard­ware to add a battery later during their solar instal­la­tion,” he said.