Local Law 97

Local Law 97 Overview

Local Law 97 (LL97) was enacted by the New York City (NYC) Council in April 2019 as the centerpiece of the Climate Mobilization Act to reduce the city’s emissions and achieve carbon neutrality by 2050. NYC buildings account for approximately two-thirds of GHG emissions in the area.

The following are key timeline periods required by the law: 

• Covered buildings are to take steps to meet new GHG emissions limits beginning in 2024.
• All covered buildings will be required to report their 2024 compliance by May 1, 2025, and by May 1 of every year thereafter.
• The limits implemented in 2024 will be the same for each year from 2024 through 2029.
• This process will repeat with stricter annual limits for each five-year period thereafter – 2030 through 2034, 2035 through 2039 – until 2040.
• From 2040 through 2049, the law may require the strictest annual limits to achieve the required goal in 2050.

The goal is to reduce emissions produced by the city’s largest buildings by 40% by 2030 and 80% by 2050.

Read more on Local Law 97

Regulation Requirements

In One New York: The Plan for a Strong and Just City (OneNYC), released in April 2015, NYC committed to its 80x50 plan, a vision for reducing GHG by 80% by 2050. The resulting Climate Mobilization Act (CMA), passed in 2019, included LL97, the centerpiece legislation requiring incremental reduction of GHG emissions starting in 2024 and ending with the achievement of the climate goal in 2050.

GHG Emissions

GHG emissions are calculated based on the amount of consumed energy and a coefficient associated with the type of fuel used. Emissions are expressed as tons of carbon dioxide (CO₂) per 1,000 Btu of energy produced (tCO₂e /kBtu), including:

• Natural gas has a GHG coefficient of 0.00005311 tCO₂e per kBtu
  • The coefficient for natural gas will not change because it represents the amount of CO₂ emitted from the combustion of each unit of gas. Improvements to the efficiency of gas systems will reduce the units of combusted gas but do not reduce the CO₂ emitted per unit.
• Utility electricity has a GHG coefficient of 0.000288962 tCO₂e per kBtu
  • The coefficient for electricity is expected to decrease over time as the production of “grid” electricity continues to become “cleaner”, with an increasing share generated via renewable sources such as solar or wind. The plan is to reduce the CO₂ emitted per unit of electricity over time targeting zero with a “clean” electricity grid.

Building Emission Limits

Building emissions intensity is defined as the emissions per square foot of gross floor area (tCO₂e/sf).

• The allowable limits on emissions intensity vary based on the occupancy type and compliance year.
• The limits are based on the requirements of the law to convert “categories of uses under the United States Environmental Protection Agency Portfolio Manager tool to the equivalent uses and occupancy groups set forth in” LL97.
• The first set of limits for 2024 through 2029 are based on the 75th percentile of each category of buildings in NYC using the 2017 benchmarking data, effectively requiring all covered buildings in NYC to meet the performance of those levels in the 2024 through 2029 period.
• The limits in the following periods are goals the city has determined to be reasonable requirements of building improvements and greenhouse gas intensity (GHGI) reduction. The city apparently envisions the GHGI reduction to be attainable primarily through electrification by building owners and reduction of emissions from the electrical grid.
• The Multifamily Housing R-2 occupancy group, for example, has an annual building emissions intensity limit of 0.00675 tCO₂e /sf from 2024 through 2029, and the limit drops to 0.00334664 tCO₂e/sf in the next period of 2030 through 2034. This requires approximately a 50% reduction in 2024 allowable GHG emissions before 2030.

Penalties

Buildings that exceed their emissions intensity limit are subject to a penalty of $268 for each tCO₂e per year over the limit. Therefore, if a building exceeds its emissions allowance by 100 tCO₂e in a given year, it will incur a penalty of $26,800.

How We Can Help

Thornton Tomasetti takes climate action seriously and has assisted clients for decades on all types of structures throughout NYC. We have established an excellent working relationship with the NYCDOB and can help you in auditing existing building systems, reviewing energy usage and emissions levels and preparing the required annual building emissions report, along with any required follow-on work, such as preparing contract documents, assisting with bidding and negotiation, and performing site visits and construction administration services.

How do we do this? Our specialized teams are already helping clients work toward the ambitious LL97 goals in a variety of ways:

• Our Renewal practice makes it easier to reuse existing buildings through renovation, rehabilitation and retrofit of the structure and building envelope.
• Our Sustainability & Resilience practice can help you properly account for and reduce both operational and embodied carbon via life-cycle assessments and energy modeling.
• Our Façade Engineering practice champions a sustainable design approach, integrating innovative materials and technologies to optimize energy efficiency, reduce carbon emissions and enhance the overall building performance, all while delivering the utmost design aesthetics.
• Our Structural Engineering practice remains at the forefront of building design and decarbonization by incorporating GWP thresholds into product specifications and through the use of innovative tools like Beacon, a Revit plug-in that helps engineers track and manage embodied carbon throughout all stages of design.

Contact Us Today

Contact us with any immediate questions or to request any Local Law 97 guidance or services, please complete the form below and one of our experts will contact you directly.