Twin Cities Energy Mapping Tool
Jenny Edwards, Emmy Waldhart
A building’s core characteristics, primarily its era of construction and size, can help determine which measures are cost-effective priorities for energy efficiency. For example, only 25 percent of pre-war homes in the Twin Cities currently have wall insulation, compared to nearly all homes built to codes introduced after the energy crisis. Similarly, commercial construction style has evolved dramatically over the last century, from smaller masonry buildings to larger steel frames. At the regional scale, these construction eras created patterns of dominant building styles.
These patterns are increasingly important for planning community-scale energy programs. By enhancing the building stock data with population averages of the efficiency potential for buildings of different eras, one can estimate the savings from different efficiency strategies across the region. As an example, the image below illustrates patterns of commercial buildings by four size classes.
CEE researchers have developed a GIS-based tool that can visualize, measure, and compare efficiency programs at the community scale for the Twin Cities metro area. The tool’s building database compiles the most complete and up-to-date information from a variety of sources. Individual building information was extracted from tax records found in the 2009 Metropolitan Council Regional Parcel Dataset and in reports generated by Anoka County, Dakota County, Ramsey County, Scott County, Minneapolis, Minnetonka, Eden Prairie, Brooklyn Park, Edina, Plymouth, St. Louis Park, Bloomington, and Maple Grove.
To fill in the data gaps in the tax records, project staff used building footprint files created from Light Detection and Ranging Data (LIDAR). When LIDAR detected a building but the tax records did not include square footage information, the project team calculated square footage from the building footprint. While not a perfect means of estimation, it helped account for square footage in cases when it was not recorded for tax purposes. In the example below, staff used both tax parcel information (green text) and LIDAR calculations (blue text) to populate the square footage of the Mall of America.
Energy scenario assumptions were developed from industry best practices about the efficiency potential of Minnesota’s building stock. Current scenarios focus on residential and commercial energy efficiency, but can be expanded to include additional sectors and clean energy measures, including renewables.
CEE is currently applying the tool to evaluate different climate and energy options for the City of Minneapolis, and for internal market potential studies. It is intended to help cities in the metro area meet their clean energy goals, assist regional planning professionals, and conduct community-scale market potential studies. For example, researchers used calculations created from CEE’s building science expertise to determine which areas of the metro could save the most energy by installing attic insulation in single family residential homes:
CEE would like to thank Maple Grove, Minneapolis, Minnetonka, Ramsey County, and St. Louis Park for providing free data for this project.