NYC to make fossil fuel consumption ancient history
In the third in our series of blogs discussing carbon reduction targets, senior cities consultant Alexan Stulc examines the impact of Mayor de Blasio’s mandated fossil fuel caps
In September 2017, Mayor de Blasio announced that New York City was to become the first city to mandate that existing buildings must take measures to dramatically cut their greenhouse gas (GHG) emissions. Two months later, New York City Council Member, Costa G. Constantinides, followed the Mayor’s pledge with a bill to ‘establish limitations on onsite fossil fuel consumption and energy usage for certain buildings’.
Crafted to support New York’s ambitious goals for reducing GHG emissions 80% by 2050 and limiting global warming impacts to 1.5°C, there is no doubt that this bill will have a tremendous effect on the City’s buildings and the way they consume energy. What remains unclear is exactly what its impact will be, and who will be most deeply affected.
Why implement a mandate on existing buildings?
Buildings produce about 66% of GHG emissions in New York City, some 60% of which are attributed to fossil fuels. Based on reporting by building owners, the most significant driver of fossil fuel use is the combustion of natural gas or fuel oil to provide heating and hot water. Given this evidence, it follows that regulating fossil fuel use in buildings is the most direct means to reducing citywide GHG emissions.
The proposed mandate creates occupancy-based targets for onsite fossil fuel use in private buildings with an area greater than 25,000sf, and City-owned buildings greater than 10,000sf. It states that building owners have until 2030 to perform the work necessary to meet these targets, and thereafter report fossil fuel use on an annual basis to ensure continued compliance.
How fossil fuel consumption is measured
The most commonly used metric to measure a building’s energy use is known as ‘energy use intensity’, or EUI, which describes the energy used (kBtu) per square foot (sf) per calendar year (yr).
EUI is often separated into ‘site’ and ‘source’ values. Site EUI reflects the amount of energy consumed by the building itself, whereas source EUI represents the total amount of raw fuel used – taking into account losses incurred from production, transmission and delivery.
The targets set out in New York City’s mandate focus on site EUI, as the losses associated with fossil fuel delivery are relatively insignificant. According to the bill, buildings covered by the mandate will be required to achieve these targets based on ‘adjusted fossil fuel use’ – defined as the total amount of fossil fuel consumed by the building in a year, less exemptions and exceptions for green energy, cogeneration systems, emergency generators in critical facilities, and biofuels.
In many cases, process loads – energy consumed for manufacturing, industrial or commercial processes – are also exempt from fossil fuel use calculations. This is to ensure that the mandate does not negatively impact business operations or building resiliency across the city.
Understanding the targets
Notwithstanding exemptions for affordable and rent-regulated residential units, the proposed fossil fuel use targets range from 35 to 100 kBtu/sf/yr depending on occupancy type.
To gain a more accurate understanding of how the proposed mandate will affect New York City buildings, we looked at two distinct building uses – ‘office’ and ‘multifamily housing’ – and estimated the current median fossil fuel EUI for each based on an analysis of 2015 New York City benchmarking data. Table 1 shows the estimated mean fossil fuel EUI compared to the proposed target for each.
Current benchmarks and proposed targets for offices and multifamily housing
|Self-Reported Property Type||Buildings Evaluated||Median Site FF EUI (kBtu/sf/yr)||Target Site FF EUI (kBtu/sf/yr)||Median-Target Difference (%)|
Offices covered by the mandate – currently some 1,300 buildings, representing 380 million sf – must meet a target of 35/kBtu/yr. Benchmarking data shows us that, on average, fossil fuels consumed by office buildings in the City account for approximately 40% of total energy use, or 31 kBtu/sf/yr. In this case, more than half of existing office buildings covered by the mandate would already meet the specified target for commercial properties.
Figure 2: Distribution of office building site fossil fuel EUI
Multifamily housing covered by the mandate – currently representing an astounding 1.16 billion sf of the City’s built environment – will be required to achieve a fossil fuel use target of 50 kBtu/sf/yr. Buildings containing one or more affordable units will receive an additional 5 kBtu/sf/yr of leeway.
Unlike commercial offices, however, in multifamily houses fossil fuels can account for over half of total energy use – or 66 kBtu/sf/yr. Because of this, nearly 60% of multifamily buildings would need to pursue retrofits to achieve the mandated targets.
Figure 3: Distribution of multifamily housing site fossil fuel EUI
What happens if these targets aren’t met?
At the moment, there are is no legislation in place that establishes the measures that should be taken if targets aren’t met. To address this, the bill states that administering agencies must bring together working groups of industry professionals, businesses, tenants, tenant organisations, and other relevant stakeholders who, over the next three years, are tasked with developing recommendations for penalties, as well as additional requirements for whole-building energy use and targets for rent-regulated buildings. These will then be considered, and ultimately established by rule.
The future of fossil fuel use in New York City
Over the last few years, BuroHappold Engineering has been working closely with New York City to develop its Roadmap to 80 x 50 and the recently-released 1.5°C: Aligning New York City with the Paris Climate Agreement. These initiatives are themselves indicative of the City’s commitment to reduce GHG emissions, and the mandate and bill of 2017 represent the next bold step in making these plans a reality.
As the targets currently stand, the bill will have a far greater impact on some areas of the built environment than others – which may be something that needs to be addressed as discussions unfold over the next three years. What is clear, however, is that New York City is leading the charge against climate change, and setting a high standard for other major cities to follow.