Urbint Interactive Map for Energy Consumption and Greenhouse Gas Emission of NYC

Contributors: Xin Xie and Kevin Han

Executive Summary

In this blog we present the Urbint Interactive Map for visualizing New York City energy consumption and greenhouse gas emission. The Urbint Interactive Map provides flexible controls for visualizing data in multiple ways so that one can quickly obtain various information regarding NYC energy efficiency.

This is a publicly available online tool through which we hope to increase public awareness of energy consumption issues, particularly in the building and design of new modern luxury condominiums.

Introduction

Energy efficiency of buildings is a big concern not only for city residents, but for the builders, owners, and urban infrastructure planners as well. Urban operators are interested in reducing maintenance costs and making the infrastructure as resilient as possible. Urban residents might complain about energy inefficiency of their buildings when they get a huge bill in the winter for keeping their living space warm. Finally, the builders and owners of high-end condominiums and cooperatives might be criticized for making buildings more and more luxurious at the expense of “greenliness”.

To help address these growing concerns, NYC has issued a NYC Benchmarking Law, requiring owners of large buildings to annually measure their standardized energy and water usage. Consequently, since 2011, datasets of energy consumption and greenhouse gas emission of large buildings have been made publicly available by the NYC Mayor’s Office of Sustainability.

Using this data, the Mayor’s Office of Sustainability and New York University’s Center for Urban Science and Progress have made a comprehensive “New York City Energy and Water Performance Map”. However, it only extends to the reporting year of 2015.

Here we look at the updated 2016 energy consumption data, as well as the 2017 Department of Finance annual building value data. We particularly want to take a closer look at the energy consumption of condos and cooperatives with high value assessments.

Interactive Visualization Platform for Urban Data

We have developed a generic and interactive data visualization platform for urban data using Mapbox GL. Our design was inspired by the “Manhattan Population Explorer” made by Justin Fung. The interface of the NYC energy consumption visualization is shown below:

Figure 1. 2016 NYC energy consumption visualization (URL: https://urbint.github.io/visualization_nyc).

The interactive visualization can be controlled in three ways:

1) Control panel that can be seen in the the upper-left corner in the above figure. Its options include building type, building built year, borough location, and data source for display. Three data sources are provided for display: weather normalized source energy use intensity (EUI), EUI change from previous year, and the total GH gas emission.

2) Zoom and viewing angle control for intuitive zooming and 3D rotation control using a keyboard and mouse. The 3D rotation can be controlled by holding control/command key and click-dragging your mouse.

3) Pop-up tips of a building can be displayed by clicking on the base area of the 3D bar of the corresponding building as shown below:

Data Visualization and Analysis

The weather normalized source EUI (Energy Use Intensity) value for each building is shown as a 3D bar, where the height represents the EUI value. For easy visualization, the EUI value is also color coded — red is for high values and green is for low values. Total black means the value is zero.

A few observations can be made by playing around with the visualization tool:

Condominium consume more energy. Energy consumption for six combinations of building types and built years in Manhattan are shown in the following figure:

Figure 2. Comparison of weather normalized EUIs of pre-war, post-war, and modern condos and cooperatives in Manhattan.

One clear trend that can be seen in Figure 2 is that the condominium buildings consume more energy than cooperative buildings as they display a higher percentage of red bars. This is particularly true for modern condos. A similar trend is also observed for the other 4 boroughs.

Figure 3. Weather normalized EUIs of all buildings in Brooklyn (BK), Queens (QN), the Bronx (BX) and Staten Island (SI).

To get a more quantitative measure for this trend, we look at the mean value of the EUI for different types of buildings and built years. For condos, Manhattan has the highest EUI of 156.6 kBtu/ft2. For cooperatives, Queens has the the highest at 123 kBtu/ft2.

Modern condominiums consume the most energy. Energy consumption can be broken down into more granular categories. The results are shown in Table 2.

Looking at the same areas, the cooperative buildings have significantly lower mean EUI values. This is shown in Table 3.

NYC greenhouse (GH) gas emissions can be visualized in a similar way. The following pictures show the GH gas emission by different types of buildings and built years.

Figure 4. Total greenhouse gas emission intensities of pre-war, post-war, and modern condos and cooperatives in Manhattan.
Figure 5. Total greenhouse gas emission intensities of all condo and cooperative buildings in Brooklyn, Queens, the Bronx, and Staten Island.

Condominiums have significantly higher GH gas emissions. The following tables show the breakdown of GH gas emissions by building years and types for all 5 boroughs.

There is great diversity in energy efficiency. Energy efficiency of high-end luxury condos is quite diverse and there are a few extreme cases. For example, 157 WEST 57 STREET (built in 2009), 15 CENTRAL PARK WEST (built in 2005), and 20 WEST 53 STREET (built in 2012) are three modern luxury buildings that had energy consumption of 287.2 kBtu/ft2, 222.2 kBtu/ft2, and 386.0 kBtu/ft2, respectively. This is much higher than the average of 156 kBtu/ft2 for condos in Manhattan.

However, the wide range of energy consumption in modern condos implies that luxuriousness is not the sole determining factor of energy consumption. Other factors can include thickness and the material of the building walls, as this highly affects insulation. For example, the thick walls that exist predominantly in pre-war buildings trap heat inside, thereby reducing the need for huge amounts of energy for heating. On the other hand, the glass exteriors of most modern buildings create a greenhouse effect that heats up the interior during the summer, increasing energy consumption of air conditioners used to cool down the building.

Since the thickness and the material of the building walls, as well as general building structure, are correlated with the year in which a building was built, it is tempting to conclude that built year is a significant factor in determining building energy usage. While the thick walls in pre-war buildings do have their advantages, pre-war buildings also often have window air conditioners installed for each individual unit as opposed to the highly efficient central air conditioning systems used in modern buildings. Furthermore, modern buildings are also more likely to adopt energy-saving technologies in their architectural design, implementing heating, ventilation, and air conditioning (HVAC), solar panels, green rooftops, etc.

Leadership in Energy and Environmental Design (LEED) is a green building certificate program that makes efforts to develop environmentally friendly buildings. We have highlighted the LEED buildings in the visualization in cyan color. Out of the six LEED condos and cooperatives in Manhattan, four are very energy efficient. The other two luxury buildings, 450 WEST 42 STREET and 151 EAST 58 STREET, are shown in red. This goes to show that even LEED certificates won’t tell us the whole story. It is hard to tell that either modern luxury buildings or old buildings consume more energy by looking at only a few cases. Therefore, in addition to providing a visualization tool, we show some analysis in the next section to help us understand what is likely to correlate to energy consumption.

We end this section with a look at how energy consumption and greenhouse gas emission relate to each other. The following plot reveals a very strong positive correlation (0.91) between them, indicating that the condos and cooperatives with high energy consumption tend to release large amounts of greenhouse gas. Note that the total greenhouse gas emission includes both direct and indirect parts. However, even with just indirect emission, the correlation coefficient reaches 0.73. An ideal building design would have greenhouse gas emission and energy use compensating each other. This potentially presents a good opportunity for urban infrastructure operators and building owners to improve their operations.

Figure 6. Scatter plot of Building Total Greenhouse Gas Emission (Direct and Indirect) vs. Weather Normalized Source EUI.

Energy Consumption Model

To gain a deeper understanding of the factors that might impact energy consumption, we constructed an energy consumption model using various building features. We chose a Gradient Boosted Model (GBM) and show the feature importance below. The feature importance ranking can be roughly interpreted as the impact of each building factor on energy consumption.

Figure 7. Feature Importance for the Energy Consumption Prediction.

Both the assessed value per square foot and built year are identified as top features. This is consistent with the visualization, as well as the recent article “High-end condos are eating up energy”. The residential unit count also plays an important role as it is possible that with more units additional common utilities need to be provided.

We also plot the model performance for the test data. The predictions show a fair correlation of 0.53 with true values. The unresolved variance can be further reduced by introducing more specific features such as building infrastructure information, energy saving characteristics, specific architecture design, resident behaviors, weather data, etc.

Figure 8. Scatter plot of Predicted EUI versus the Actual EUI for the test data.

Conclusion

We have presented here a 3D energy consumption visualization tool that can be used to look into energy efficiency of NYC buildings. Using this visualization, we observe that modern condos consume more energy on average than other buildings. Some of the high-end luxury condos are the worst in terms of energy consumption. Furthermore, energy efficiency of high-end condos is quite diverse. Some high-end condos are much “greener” than the worst cases. This indicates that in the last several decades, introduction of luxury features for condos and cooperatives that increase energy consumption eat away at some of the advances made in building technologies that save energy.

At Urbint, we leverage urban data to provide business and scientific insights to urban operators. We often incorporate building features in our predictive models as they play a crucial role in modeling urban problems.

Acknowledgements

We thank Anna Vasilyeva, Jiabo Li, and Sofia Song for providing good suggestions and helping with the writing of this blog.

Reference

Green Buildings & Energy Efficiency, http://www.nyc.gov/html/gbee/html/plan/ll84_scores.shtml

Manhattan Population Explorer, https://github.com/citrusvanilla/manhattanpopulationexplorer

High-end condos are eating up energy, http://www.crainsnewyork.com/article/20180514/FEATURES/305149999/high-end-condos-are-eating-up-energy

Luxury Buildings Help Drive Climate Change, Says New Study, https://www.6sqft.com/luxury-buildings-help-drive-climate-change-says-new-study