Building-specific quantification of fossil fuel CO2 emissions in an urban domain: the case of Indianapolis, US

Quantification of fossil fuel CO₂ emissions from the bottom-up perspective is a critical element in interpreting atmospheric CO₂ measurements in addition to providing critical emissions mitigation information. Recent research and decision-support has placed emphasis on quantification of emissions for urban domes with sector specificity. Here we present results of the Hestia Project, an effort aimed at quantifying fossil fuel CO₂ emissions at the building and road segment scale for the city of Indianapolis as part of the INFLUX experiment. To calculate CO₂ emissions for buildings, we use a combination of county-level estimation from the Vulcan Project and distribute those emissions via an allocation method that utilizes a building energy simulation tool - eQuest (DOE). eQUEST is based on a series of building typologies and has a large number of input variables in order to quantify energy consumption. The simulation process uses default values when the actual data are inaccessible or non-existent. Our method is based on the construction of 22 commercial, 18 industrial, and 8 residential building types. This classification requires specification of building vintages and sizes. To calculate the total floor area of buildings from building heights, remote sensing data are used. The DOEs regional energy surveys, CBECS, RECS and MECS data for the East North Central Census Division, are used to calibrate hourly profiles for different building types. Previous published results for Indianapolis have been substantially updated by using additional data on natural gas pipelines. A more accurate, statistically-based building height assessment has been made using improved lidar data. The reclassification procedure converting Assessor's parcel types into Hestia prototypes, has been revised and improved. More accurate statistics have been calculated and corresponding diagrams and thematic maps have been prepared. Development of a powerful user-friendly information system for decision-makers is in process. That system will allow city environmental managers and regional planning agencies to make analyses of CO₂ emissions for inquired sector and period. Of the townships in Indianapolis, Central Township has the largest emissions through the whole year while Wayne is the largest Industrial emitter. The commercial sector building emissions peak during at 7:30 am and 5 pm while the residential sector has peaks at 6 am and 6 pm. The Industrial sector has one peak at 1:30 pm. The relative proportions of those peaks vary with seasons of year. In contrast, their positions in monthly and diurnal profiles appear stable.