Methodology

New York City rooftop solar, 2002 to 2026

What the map shows

Each dot is one completed solar electric project in one of the five boroughs of New York City, drawn at its reported location. As the timeline plays, projects appear in the year their incentive application was received, so the animation traces where and when solar spread across the city.

Data source

All points come from a single public dataset: Solar Electric Programs Reported by NYSERDA: Beginning 2000, published by the New York State Energy Research and Development Authority on the NY Open Data portal (dataset id 3x8r-34rs). The data used here was pulled on July 29, 2026.

This dataset covers projects that went through NYSERDA's NY-Sun incentive program. It is the most complete public, address-level record of distributed solar in New York, but it is not a literal census of every panel ever installed: systems built entirely outside NYSERDA programs may not appear, and utility-scale projects larger than 5 megawatts (alternating current) are excluded by NYSERDA. In practice, the overwhelming majority of residential and small-commercial rooftop systems in New York City run through NY-Sun, so coverage of the rooftop segment shown here is high.

New York City does not publish a more complete address-level alternative. The city's own solar datasets are narrow (the Local Law 24 set covers only city-owned buildings). The exhaustive records sit with the utility (Con Edison interconnection) and the Department of Buildings (DOB NOW solar job filings), neither of which is released as a clean point-level public dataset.

Filters applied

Geography: county is one of Bronx, Kings (Brooklyn), New York (Manhattan), Queens or Richmond (Staten Island).
Status: project_status = "Complete". Pipeline (not-yet-built) projects are excluded.
Location: a valid latitude and longitude is present, and the point falls within a New York City bounding box (40.45 to 40.95 N, -74.30 to -73.65 W). A small number of records with missing or out-of-range coordinates are dropped.

After filtering, the map contains 59,545 completed installations totaling about 616 megawatts of nameplate direct-current capacity.

Why the line breaks after May 2025

The per-year chart shows a steep fall in 2025 and a near-empty 2026. That is not a collapse in rooftop solar. It is the incentive program this dataset tracks running out of money in New York City.

Applications fall off a cliff in a single month:

Month	NYC applications received
March 2025	599
April 2025	617
May 2025	737
June 2025	185
July 2025	227
Monthly average, July 2025 to June 2026	about 120

The date lines up with a specific administrative event. NYSERDA allocates NY-Sun incentives in capacity blocks by utility territory and sector, and when a block is fully subscribed it closes. Per NYSERDA's Con Edison dashboard, the Con Edison residential Block 10 closed on May 29, 2025, exhausting the residential megawatt-block capacity for the territory that covers most of New York City. The nonresidential block for systems up to 200 kW had closed on May 1, 2025. NYSERDA's July 2025 operating plan update replaced the closed residential block with a narrower SEEF block aimed at low- and moderate-income customers.

Because this dataset is a record of NY-Sun program participation, a project with no incentive to apply for generates no row. The composition of what survives confirms the mechanism. Comparing average monthly applications in January to May 2025 against June 2025 to June 2026:

Segment	Before	After	Change
Residential, outside a disadvantaged community	376	48	-87%
Residential, inside a disadvantaged community	169	30	-82%
Non-residential	60	43	-29%

Market-rate residential, exactly the segment whose block closed, falls hardest. Non-residential holds up best, consistent with its larger block staying open until September 2025.

The federal tax credit is not the explanation for this break. The Section 25D residential clean energy credit was repealed by Public Law 119-21, signed July 4, 2025, for expenditures made after December 31, 2025 (see the IRS guidance and the Congressional Research Service summary). That is a month after the break in this data, and it would produce the opposite shape: a rush to finish systems through late 2025, then a fall in 2026. It may well be adding to the weakness in the 2026 figures, but it cannot have caused a drop that had already happened.

A second, smaller effect: the map is filtered to completed projects, and projects take time to move from application to completion, so the most recent years are also understated by that lag. As of this pull, New York City applications received in 2025 number 3,683 complete plus 521 still in the pipeline; for 2026, 140 complete plus 346 in the pipeline. Only the completed ones are drawn.

For both reasons, the 2025 and 2026 bars are drawn in a muted color and fenced off. They should not be read as a measure of how much solar New York City installed in those years.

How each field is used

Map element	Source field
Dot position	`latitude` / `longitude` (NYSERDA-geocoded)
Year on the timeline	`date_application_received` (year)
Dot size	`totalnameplatekwdc` (larger systems read larger)
Home vs. business color	`sector` (Residential vs. Non-Residential)
Borough	`county`

Borough rates (per square mile and per resident)

The borough panel can show totals, installations per square mile of land or installations per 10,000 residents. The denominators are fixed reference values, not from the solar dataset:

Borough	Land area (sq mi)	Population (2020)
Manhattan	22.83	1,694,251
Bronx	42.10	1,472,654
Brooklyn	69.40	2,736,074
Queens	108.53	2,405,464
Staten Island	58.37	495,747

Land areas are the U.S. Census Bureau land-area figures for each county (water excluded). Population is the 2020 Decennial Census count for each county. Rates divide the cumulative installation count for the selected year by these constant denominators; the denominators do not change over the timeline, so early-year rates are indicative rather than point-in-time accurate.

Assumptions and limitations

Application date, not switch-on date. The timeline year is when the project's application was received, which can precede the date the system actually began producing power by months. It is used because it is populated for every record; a completion date is not consistently available.
"Rooftop" is an approximation. The dataset does not flag rooftop versus ground-mount directly. In New York City, distributed residential and small-commercial solar is overwhelmingly rooftop, but a small number of canopy or other mounts are included.
Counts are projects, not buildings. A single address could in principle host more than one project record.
Capacity is nameplate, not output. Megawatt figures are rated direct-current capacity, not measured generation.
Geocoding is as published. Positions are taken directly from NYSERDA and were not independently re-geocoded.
2025 and 2026 are not comparable to earlier years. See why the line breaks after May 2025.

Reproducing the numbers

The borough totals and the statewide figures can be reproduced against the live API. For example, completed New York City projects by borough:

https://data.ny.gov/resource/3x8r-34rs.json?$select=county,count(*),sum(totalnameplatekwdc)&$where=county in('Bronx','Kings','New York','Queens','Richmond') AND project_status='Complete'&$group=county

The exact pull and transformation script is in data/fetch.py in this project.