Opinion: Why occupant density and better data should be included into NYC’s Local Law 97

In 2019, the New York City Council passed Local Law 97 to regulate the amount of carbon that buildings can emit, and they emit a lot. It is estimated that buildings are responsible for nearly 70% of carbon emissions in the city. According to the Urban Green Building Council, Local Law 97 is “the most ambitious building emissions legislation enacted by any city in the world.” It  is indeed ambitious, and well-intentioned, but it is also flawed.

The problem is how the law calculates a building’s carbon performance and subsequent caps on emissions. Caps are calculated based only on building size, without any consideration for occupant density. More granular data from buildings, when coupled with demands on the electric grid, can better capture real-time building performance, including a building’s energy efficiency and its ability to respond dynamically to grid conditions, weather and occupant needs. 

A team of engineers and data analysts from engineering firm JB&B, researchers from the Jacobs Urban Tech Hub at Cornell Tech and leading New York City building owners have joined forces on an initiative called Benchmark 8760. While carefully preserving occupants' privacy, this yearlong study explored how to securely collect hourly data and how this data can be used to improve the precision and fairness of building performance assessment tools. 

Currently Local Law 97 does not consider hourly data, weather or occupant density in its carbon accounting, despite the availability of the data. While the New York City Department of Buildings did propose an opt-in option for time-of-use accounting this past October, their calculation methodology is overly complex and likely to discourage building owners from using it.  

This is problematic because “load shifting” – understanding when the energy from the grid is greener and cleaner – will be crucially important as we move toward decarbonizing the electricity grid. The state has ambitious renewable energy goals. It is planned that 80% of the state's electric grid will come from renewables by 2050. 

As we transition to a greener grid that is less dependent on fossil fuels and more dependent on renewable solar and wind power, our time-of-day power usage becomes more important to the resiliency of the grid and overall carbon management. This problem will only get greater as we transition towards total building electrification. In the all-electric future that many predict, we will need buildings that work more closely with the grid, taking into account a more precise look at when energy is being used.

In addition, Local Law 97 does not consider occupant density in its calculations at all. Building density today varies widely as work from home has taken hold for nearly half of all office workers in the city. Without a means of tracking and recording hourly people counts, building systems are not typically adjusted to match what building occupants actually need. This issue was evident during the pandemic, where we saw that many buildings, while empty, still used nearly as much energy as if they were fully occupied. This speaks to how far we have to go to improve building system management in order to meet the new demands of a low-carbon built environment.

We need to get smarter about and more sensitive to how and when we use energy. We recommend that the industry improve existing benchmarking platforms and building performance standards to integrate hourly data into emissions calculations before Local Law 97 goes into effect in 2024. Simply put, building performance assessment tools like Local Law 97 should have the capability of integrating occupancy, time of day and weather data. 

Ultimately, when we use more granular hourly data to evaluate building performance, we can get much more predictive regarding energy usage. This insight will be crucial for a greener grid powered largely by renewables. Our initiative has shown how new technologies can enable the safe and secure collection and reporting of hourly data. 

To help amplify this opportunity to use building performance data more intelligently, this platform was built as an open source project. We are sharing our insights and resources with the industry in order to spur action to rethink Local Law 97 before it fully goes into effect in 2024. 

We need more platforms like Benchmark 8760 that provide accessible, open source urban tech products for stakeholders to enable a more affordable, cleaner and less carbon-dependent future.