LL97 Fine Estimator - NYC Buildings Over Their Carbon Cap

Ranks NYC buildings by their estimated Local Law 97 carbon fine for 2024-2029 and 2030-2034, using each building's own LL84 benchmarking energy data, the Department of Buildings emissions limits by property type, and the $268 per tonne CO2e penalty. For retrofit contractors, ESCOs, energy consultants, lenders and brokers who want a sales or diligence list of buildings with the biggest exposure. An estimate for screening, not legal or compliance advice.

Example inputs

1. Default: top 50 buildings by estimated 2030-2034 fine

{}

2. Manhattan offices and hotels over the cap by at least $100k a year

{ "boroughs": ["Manhattan"], "propertyTypes": ["Office", "Hotel"], "minFineUsd": 100000, "maxBuildings": 200 }

3. Look up specific tax lots (also shows buildings with no fine)

{ "bbls": ["1008350041", "1013070001"], "sortBy": "fine2024" }

Input guide

Field	What it does
reportYear	LL84 year to read (2024 latest). Future years assume the same energy use.
maxBuildings, sortBy	How many to return and whether to rank on the 2024-29 or 2030-34 fine.
onlyOverLimit, minFineUsd, minGfaSqft	Filters. Covered buildings are over 25,000 sq ft.
boroughs, propertyTypes, bbls	Narrow the list; bbls overrides the over-the-cap filter.
includeSuspectData	Keep filings with implausible energy use (default off, they are usually unit errors).
finePerTonneUsd	Penalty rate, $268 in the rule.

Output

Field	Meaning
rank, propertyName, address, borough, bbl, parentProperty	Which building
primaryPropertyType, ruleCategories, gfaSqft	LL84 uses mapped to the rule's property types
emissionsTco2e2024, limitTco2e2024, fineUsd2024_2029	Estimated annual emissions, cap and fine for 2024-2029
emissionsTco2e2030, limitTco2e2030, fineUsd2030_2034	Same for 2030-2034 (electricity factor drops to 0.000145)
ll84TotalGhgTco2e, siteEuiKbtuSqft, energyStarScore	Cross-checks
confidence, notes	high / medium / low and why

Sample row (trimmed): {"rank":2,"propertyName":"Co-Op City","borough":"Bronx","gfaSqft":22042704,"emissionsTco2e2030":132327.6,"limitTco2e2030":67748.8,"fineUsd2030_2034":17307108,"confidence":"medium"}

Model and assumptions

• Emissions = LL84 energy use of the report year x LL97 coefficients: electricity 0.000288962 tCO2e/kWh (2024-29) and 0.000145 (2030-34); natural gas 0.00005311 per kBtu; fuel oil No. 2 0.00007421, No. 4 0.00007529; district steam 0.00004493 then 0.0000432; other fuels from 1 RCNY 103-14. Fuel oil No. 5/6 is billed at the No. 4 factor (the rule lists none).
• Limit = sum of floor area x the per-property-type emissions factor in 1 RCNY 103-14 (60 ESPM types, 2024-29 and 2030-34 tables, transcribed from the DOB rule PDF).
• Fine = max(0, emissions - limit) x $268, per year. Energy use is held constant through each period.
• Not modelled: RECs and offsets, time-of-use electricity option, good-faith / mitigated penalties, rent-regulated housing (35%+ units) which follows a prescriptive path with no fine, the 2024-25 option to use the older occupancy-group limits, deductions, and anything after 2034. Houses of worship are exempt and shown with a zero fine. Filings with energy use above 600 kBtu/sq ft (1,500 for labs and data centers) are treated as data errors and excluded by default.

FAQ

Source? NYC Open Data, "NYC Building Energy and Water Data Disclosure for Local Law 84", DOB. Self-reported by owners, so errors exist. Why do some buildings have medium or low confidence? A use type is mapped to the nearest rule category, or part of the floor area has no rule category. Is the real fine this number? The real bill depends on the owner's actual filed emissions, the property types the owner's design professional selects, and deductions. Use this to rank and prioritise, not to quote.

Limits

LL84 data lags a year. No energy data in LL84 for non-reporters (skipped). Estimates only.

Price

building-scored $0.003 per building returned. Example: the default 50 buildings = $0.15; a 500-building list = $1.50.