Commercial Buildings Energy Consumption Survey (CBECS) and the road to carbon neutrality.
Have you ever asked how much energy the average commercial building in the United States consumes in a year? How about where the energy comes from or how the energy consumption varies by region or building type? Look no further. This data along with a wealth of other commercial energy consumption data is available in the Commercial Buildings Energy Consumption Survey (CBECS). For years CBECS has been an invaluable tool to energy analysts and researchers. The survey is based on millions of buildings across the country and includes extensive data on building characteristics such as year of construction, geographic region, fuel sources, and building function to name a few.
The CBECS data has just been released for the survey conducted in 2012. Prior to the release of this data, the most recent CBECS data available was from a survey conducted in 2003. As such the relevance of the data from the 2003 survey was beginning to wane. Now that the data from the 2012 survey has been released let’s examine a few details regarding the performance of the 2012 existing building stock relative to that of 2003 to see how building energy performance has improved.
In 2003 the average Energy Use Intensity (EUI) of all buildings in the U.S. was 91.0 kBtu/ft2*yr. In 2012 that value fell to 80.0 kBtu/ft2*yr which represents a 12% decrease in energy consumption per commercial building floor area over a 9 yr period (Figure 1). While that percent decrease is substantial, is it enough to reach net zero by 2030? It is not when looking at the data from commercial building energy consumption data alone.
Figure 1
The CBECS data also breaks the energy consumption down by fuel source. When looking at this data, it is apparent that electricity consumption relative to building area did not change substantially over this time period, 49.7 kBtu/ft2*yr in 2003 vs. 48.7 kBtu/ft2*yr in 2012. The energy consumption reduction per building area between 2003 and 2012 is accounted for by a reduction in natural gas, fuel oil, and district heat. Electricity was also the single largest fuel source for commercial buildings in 2003 and 2012.
How much of the electricity was generated by renewable means during each of these surveys? This data is not included as part of the CBECS data but is relevant to achieving net zero carbon emissions. This data can be acquired from the U.S. Energy Information Administration (EIA) Monthly Energy Review (Figure 2). In 2003 all renewable electricity production accounted for 9.1% of the total electricity produced. In 2012 all renewable electricity production accounted for 12.2% of the total electricity produced. Although the percentage of the total electricity produced increased only 3.1%, it represented a 39.2% increase in renewable electricity production. This happened because the total electricity production from 2003 to 2012 increased by 4.2%. Electricity produced by natural gas increased by 88.6% while electricity produced by coal fell by 23.3%. Nuclear energy production remained relatively constant with a growth of only 0.7%.
Figure 2
Using the data from electricity production the EUIs can be broken out into renewable vs. nonrenewable for each respective year. If the renewable energy is removed from the EUI (assuming it is carbon neutral) the resulting EUI for 2003 is 82.8 kBtu/ft2*yr and the EUI for 2012 is 70.2 kBtu/ft2*yr or a reduction of 15.2% (Figure 3). While this shows a greater shift towards carbon neutrality, it is most likely not on track to reach net zero by 2030. This overly simplistic analysis makes the assumption that both of these shifts will remain constant and follow a linear curve over time. Regardless, it demonstrates more progress must be made in reducing energy consumption and increasing our focus on renewable energy sources.
Figure 3