Introduction - Problem
definition
\label{introduction---problem-definition}
New York City in the plan called “80 x 50” has taken the challenge of
reducing 80% of its carbon emissions, based on 2005 levels, by 2050.
Since about two thirds of the city’s emissions come from energy used in
buildings, it is fundamental for New York City and the Mayor Office of
Sustainability (MOS) to evaluate and understand the energy consumption
of the buildings in the city. As preliminary steps taken to assess the
problem, the city passed two laws aimed at collecting granular and
detailed data about the energy usage in some of its most significant
emission sources: large buildings. These two laws are Local Law 84 and
Local Law 87. [1]
Local Law 84 (LL84) requires that owners of buildings with a gross floor
area larger than 50,000 ft2 report their energy and
water consumption every year. The objective of reporting this
information is to provide the city a better understanding of energy
consumption patterns and of what drives the differences in energy usage
among the different buildings. This practice of collecting information
and comparing the energy performance of buildings is often referred to
as benchmarking and has been adopted in similar ways for several other
cities such as Chicago, Philadelphia, Seattle, San Francisco,
Washington, DC.[1] Benchmarking, which is related to the concepts of
efficiency and productivity analysis, is a way to achieve improvement
through comparison with others who are the best within the area. In
general, the concept is based on recognizing one’s shortcomings,
acknowledging that others are doing better, and learning from them to
implement in one’s case afterwards. [2]
To fully understand buildings’ energy consumption patterns, the city has
also passed Local Law 87 (LL87) in 2009, which requires an audit of
every building covered by the LL84 every decade. The audits began in
2013 and since then, every year about one-tenth of those buildings are
audited. During the LL87 audits, the auditor also makes a list of
retro-commissioning actions, which have the purpose of ensuring that the
systems in place are operating as efficiently as they were designed to
be.[1]
This project contributes to the final goal of reducing the carbon
emissions that come from buildings in designing of a metric - similar to
Energy Star Score - that can capture the particular characteristics of
New York City buildings. This developed metric takes into account
features of different building typologies and offers insights about the
reasons behind the performance of each building, in addition to possible
actions to improve that performance. This new calculated metric will be
part of an Energy Scorecard along with several Energy consumption
statistics. This Scorecard will be sent to each building owner (or
manager) complying with LL84 as a way for the MOS to give something back
to them in exchange for all the information they now have to provide to
comply with LL84. Eventually also made available online.
The underlying motivation behind this project is that simply by better
informing the building owners compliant to LL84 it is possible (and
expected) that there will be some behavioral change towards a more
efficient use of energy. That alone, i.e. sending a clear and
informative Energy Scorecard to each of the building owners, may be
found in the future to be an effective policy to significantly
contribute for a more energy efficient and less carbon intensive NYC.
Despite being an outcome that depends on many factors that are not in
our control, that is the ultimate goal of building these models and
developing this analysis.