Local Law 97 — Climate Mobilization Act emissions limits

Local Law 97 of 2019 — the centerpiece of the Climate Mobilization Act — sets greenhouse-gas emissions limits for large NYC buildings and charges a civil penalty on emissions over the limit. The first compliance period covers 2024 – 2029, with a sharply lower limit for 2030 – 2034, and further reductions beyond (NYC Admin Code § 28-320).

Unlike LL84 (data reporting only) or LL87 (audits every ten years), LL97 is a performance law — a building that emits more than its allowed tonnage of CO2e pays a penalty per ton over the limit.

This guide explains who is covered, how the annual reporting works, and what the penalty structure looks like. Educational only — not legal advice or a decarbonization plan.

What this means

LL97 assigns each covered building a CO2e emissions limit based on its property type(s) and gross square footage, for each compliance period.

• Coverage. Buildings of 25,000 gross square feet or more. Campus configurations, coops / condos, and rent-regulated buildings have specific rules and overlays (NYC Admin Code § 28-320).
• Compliance periods. 2024–2029 is the first period; 2030–2034 is the second, with materially lower limits. The law anticipates further reductions in 2035, 2040, and toward 2050.
• Emissions. Emissions are calculated from 12 months of whole-building energy use (electricity, natural gas, steam, fuel oil, etc.) using CO2e coefficients published by DOB.
• Annual report. Beginning May 1, 2025 (for the 2024 reporting year), covered buildings file an annual emissions report prepared and certified by a Registered Design Professional (RDP).
• Penalty. $268 per metric ton of CO2e over the limit, per year (NYC Admin Code § 28-320.6).

The 2030 limit is where the pressure is. Most covered buildings comply comfortably with the 2024–2029 limits with modest operational measures. The 2030 limit is much tighter and requires capital planning — envelope upgrades, electrification, heat-pump conversion — with multi-year lead times. Planning now is the point.

Common causes

• Emissions over the applicable compliance-period limit
• Missing the annual May 1 reporting deadline
• Submitting a report not prepared by a Registered Design Professional
• Using outdated emissions coefficients in the calculation
• Failing to track planned building improvements that would qualify as compliance credits

Timeline

• First report. May 1, 2025 — covers the 2024 reporting year. Annual thereafter.
• Compliance periods.
  • 2024 – 2029: first period; most buildings can meet limits with operational measures.
  • 2030 – 2034: substantially lower limits; many buildings require capital upgrades.
  • 2035+: further reductions on DOB's published schedule.
• Over the limit? The $268 / ton penalty applies per year the building exceeds its limit.

Penalties

LL97 penalties are direct and formula-based.

• $268 per metric ton of CO2e over the applicable limit, per year (NYC Admin Code § 28-320.6).
• Late or missing report: separately penalized, and the building may be deemed out of compliance.
• False certification. A filing prepared or certified by someone without the required RDP credentials, or containing false information, carries separate penalties and professional exposure for the RDP.
• Rent-regulated buildings and coops / condos have specific adjustment frameworks; consult counsel or a specialized consultant for those cases.

How it typically gets resolved

1. Identify coverage and limit. Use DOB's LL97 calculator or a consultant to determine the building's property type(s), the applicable 2024–2029 limit, and the 2030–2034 limit.
2. Collect energy data. 12 months of whole-building data across all fuels, using ConEd / National Grid utility aggregation where available.
3. Calculate current emissions. Apply DOB's CO2e coefficients. Compare to the limit.
4. Retain an RDP. The annual emissions report must be certified by a Registered Design Professional.
5. File by May 1. Use DOB's LL97 reporting portal.
6. Plan for 2030. If the 2030 limit is not achievable with operational measures alone, scope a capital decarbonization plan — envelope, heating plant, controls — with an energy consultant or MEP firm.
7. Evaluate credits and deductions. Renewable energy credits (RECs), onsite clean distributed generation, and certain deductions are available; the rules are specific.

When to hire a pro

• Registered Design Professional (RDP) — required to prepare and file the annual report.
• Energy consultant / MEP firm — for decarbonization planning, especially for the 2030 period.
• Expediter — for the DOB filing mechanics, especially if combined with other filings.
• Attorney — for rent-regulated buildings, coops / condos, or any contested penalty; LL97 has non-trivial legal complexity.

Related guides

• Local Law 84 — energy + water benchmarking
• Local Law 87 — energy audits + retro-commissioning
• DOB Class 2 — major

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