Chicago Cuts Emissions 7 Percent, Buildings Lead the Way

The City of Chicago has cut citywide emissions by 7 percent from 2010-2015, led by significant energy savings in the buildings sector.
Figure 1. Chicago Emissions Infographic 2015
Credit: City of Chicago

The City of Chicago has cut citywide emissions by 7 percent from 2010-2015, according to the greenhouse gas inventory released last week. The reduction is dually impressive because it was achieved during a period when the City experienced 1 percent population growth and 12 percent growth in the local economy.

The analysis, performed by AECOM, showed that the built environment contributes about 70 percent of citywide GHG emissions, but over the course of five years, this sector saw a 10 percent drop in carbon emissions—led by energy savings in buildings. The residential building sector reduced emissions by 11 percent, commercial buildings by 10 percent and institutional buildings (like universities and libraries) by 8 percent. Over 80 percent of Chicago’s total emissions reductions came from energy savings in buildings.

One strategy that Chicago has implemented to encourage energy savings is an energy benchmarking and transparency law for existing buildings, and its recent report, shows that the ordinance is proving to be effective. First adopted in 2013, Chicago’s law has been phasing in over the past few years and 2016 was the first year that the energy benchmarking ordinance went into full effect. In 2016, Chicago had nearly 2,700 buildings track and report energy use—eleven times more buildings than initially reported in 2014. These properties represent about 733 million square feet of space, 23 percent of citywide energy use, and about $2 billion in energy bills.

The benchmarking report shows that regular tracking and reporting is helping to reduce energy use and emissions.  Properties that have reported consistently are demonstrating annual energy reductions of 2 percent year-over-year. Combined, these energy reductions are saving the properties $17.6 million per year.

Chicago continues to see that its buildings are performing slightly above the national average, with a median ENERGY STAR score of 59 across all property types. Figure 2 shows the distribution of energy use intensity (EUI)—or how much energy a building uses per square foot—for each of the property types the city analyzes. Sectors with smaller boxes, have less variability between buildings, and the ones with bigger boxes and lines have a big range, with some buildings using 10-30 times more energy than others with the same use type. If all of the buildings at or above the median energy use intensity for their sector were to achieve a lower EUI, energy savings could reach 25 percent and yield $214 million in reduced energy bills.

Figure 2. Range of Site Energy Use Intensity (EUI) by Building Sector
Credit: City of Chicago Energy Benchmarking Report 2016

Another interesting finding shows that older buildings often have higher ENERGY STAR scores than newer properties, which is consistent with findings from several other cities.  Often, people assume that older buildings are less efficient because they may seem drafty or have older equipment. However, analysis continues to show that they perform just as well as, or better than, buildings constructed in the 70s, 80s, and 90s (see Figure 3). But, when we think about Chicago’s rich architectural history, this should make sense. Older buildings were designed to make use of the limited resources they had at the time. So, buildings may have access to daylight through orientation, skylights, or lightwells and they’re constructed with masonry materials that keep the cold out in the winter and the heat out in the summer. These legacy design decisions mean that buildings can use fewer mechanical services and electric lighting, saving energy even in a modern setting.

Figure 3. Property Floor Area and Median ENERGY STAR Scores by Decade of Construction
Credit: City of Chicago Energy Benchmarking Report 2016

But, no matter the building type or age there is still room to improve energy performance. Investment in energy efficiency and conservation in buildings brings lower energy costs, cleaner air, improved infrastructure, and new jobs for the people of Chicago. With buildings representing 70 percent of Chicago’s greenhouse gas emissions, their climate impact and contribution to the City’s carbon footprint are too big to ignore. Thankfully, Chicago is paying attention, and through strategies like the energy benchmarking ordinance and the Retrofit Chicago Energy Challenge, the City is helping all of its buildings achieve real and impactful results.

And that impact is felt beyond the shorelines of the Windy City. Through its participation in the City Energy Project, the City of Chicago has consistently been a leader among its peers, providing mentorship and idea exchange with other cities about how they, too, can drive energy savings in the building sector. 

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