From Using Less to Helping the Grid: The Building Conversation at Climate Week 2026

Climate Week NYC opens on Sunday, September 20. One independent guide counted more than 950 events this year, and about fifty of them are about buildings.

For a decade the building side of this conversation has followed one script. Buildings produce about 70 percent of the city's emissions and Local Law 97 caps them, so you insulate, swap the lighting, tune the boiler, and file your numbers with the Department of Buildings every May. Use less.

This year the framing has changed. The best sessions on the buildings track are not about how little a building can use, but when it uses it, and whether it can help the electric grid rather than lean on it. The shift came from a spreadsheet at the New York Independent System Operator, not from a design trend.

The Grid Is Running Out of Headroom

Each spring NYISO, which runs the state's grid, publishes its spare capacity above the expected summer peak. In 2019 the margin was 2,227 megawatts, about 17 percent. For summer 2026 it was 417 megawatts, about 9 percent, the lowest in recent history. Since 2019 the state has added roughly 2.9 gigawatts of generation and retired 4.4.

Under a three-day 95-degree heat wave, NYISO's modeling puts that margin at negative 1,679 megawatts absent emergency measures, and Con Edison and Columbia University expect 17 such days a year by 2030, compared with four historically.

Demand is moving faster than supply. In 2022, six large-load projects, mostly data centers, were queued to connect to New York's grid, about 1,045 megawatts. By May 2026 there were 51, totaling 12,670. Most will never be built, and the state paused permits for new hyperscale data centers in July, but the city Comptroller still expects New York City's annual electricity demand to grow 25 to 30 percent by 2050.

Into that market, the city is about to send every new tall building.

Every New Building Is About to Become Electric Load

Local Law 154, the all-electric new construction law, has applied to buildings under seven stories since January 2024. The second phase arrives July 2, 2027. From then, every New Building application in the city, at any height, must be designed without on-site fossil fuel combustion, including domestic hot water. Commercial kitchens, laboratories, hospitals, and emergency generators are exempt. Boilers and gas water heaters are not.

Local Law 97 is about existing buildings, the stock we looked at in Manhattan offices that no longer work as offices. Local Law 154 is about the buildings on drafting tables now: any tower designed this fall for a 2027 filing is all-electric, and its heat, hot water, and cooking all land on Con Edison's wires. In a residential building the largest is heat, and heat happens in winter.

The Falcon Curve

In 2022, researchers at Harvard, Boston University, and the nonprofit HEET published a study in Scientific Reports on building electrification and the grid. American building energy use swings by a factor of about 1.6 over the year: low in spring and fall, a summer bump for cooling, and a much larger winter peak for heat that gas carries today. Plot the months and the graph looks like a bird in flight, wings up in January and July. They called it the Falcon Curve.

Electrify all of that heat with electric resistance, one unit of heat per unit of electricity, and the whole winter peak lands on the grid. The falcon takes off, the peak moves from summer to winter, and the state needs many times its current winter generation. Use air-source heat pumps at three or four units of heat per unit of electricity, or networked ground-source systems closer to six, and the wings flatten.

NYISO has said for years that it expects the winter peak to eventually overtake summer, and its 2026 report flagged winter as the emerging reliability problem after a January storm exposed how volatile fuel supply can be. The Building Energy Exchange and U.S. Green Building Council session at Climate Week on September 24 is titled "Buildings and the Grid: Clipping the Wing of the Falcon Curve."

New York Told Its Buildings to Stop Burning Gas. Now It Needs Them to Help Run the Grid.

The answer is not exotic: store energy inside the building so you can choose when to draw it. New York knows the principle. It is what the rooftop water tower does for water, filled when the pump is idle, drawn down when everyone showers at once.

The clearest local example is 17 years old. One Bryant Park, the Bank of America Tower, has 44 tanks in its cellar, each holding about 750 gallons of water laced with tubing. At night, when demand and prices are low, chillers freeze the tanks solid. By day the ice melts and cools the building. Same energy, spent at 3 a.m. instead of 3 p.m., the only hour the grid cares about.

The idea scales down. At the NYPD Applicant Processing Division in the landmark Sunset Park Courthouse, an overnight ice plant let the city install a smaller chiller. A heat pump water heater with a large tank does the same with hot water: heat it at 2 a.m., use it at 7. Con Edison already pays commercial buildings to shed load on peak summer afternoons, and a building with storage can say yes without anyone inside noticing.

Efficiency still comes first, which is why our principal trained as a certified Passive House architect. The cheapest megawatt is the one a tight envelope and a good heat pump never ask for. But efficiency only lowers the wings. Storage and controls move a building's weight off the peak entirely.

Why This Matters at Twelve Stories, Not Just Fifty-Five

A boutique hotel or a twelve-story residential building will not fill its cellar with ice tanks. But grid-friendliness is decided when the mechanical room is sized, in schematic design. Give the hot water system storage volume, not just heating capacity. Pick heat pumps by their output at 5 degrees, not their nameplate rating at 47. Leave room for a battery. Specify controls that can shift load, not just report it.

We wrote in June about the service core, the shafts and rooms nobody photographs that decide how a building actually functions. Same lesson applied to energy: the square footage that stores it will matter as much as the equipment that makes it.

For a long time a building's sustainability was measured inside its own walls, in energy per square foot per year. The grid is now asking a second question: what hour of what day. For once, Climate Week is not asking less of buildings. It is asking them to do something. If your project will file after July 2027, we are glad to have that conversation early.

Climate Week is not asking less of buildings. It is asking them to do something.