Decarbonization Planning Guide

Energy and GHG Emissions Benchmarking

You can’t manage what you don’t measure. Start your building on the path to improvement.

Benchmarking GHG Emissions

Benchmarking GHG emissions is an additional step after benchmarking a building’s energy use. Although Illinois jurisdictions currently don’t require buildings to report emissions, GHG benchmarking is a useful tool for meeting other sustainability goals or internally driven emissions reporting. GHG benchmarking is a crucial component in a carbon audit for a building and provides a baseline to track the impact of future improvements. 

GHG emissions benchmarking from energy alone does not paint a complete picture of a building’s emissions because it does not account for emissions from other sources such as refrigerant leakages , embodied carbon in the building materials, or emissions from purchased commodities while operating the building. However, energy consumption accounts for most of an existing building’s total emissions, so extending energy benchmarking to calculate a GHG emissions benchmark captures a large majority of a building’s GHG impact. The next figure shows how much different end uses contribute to a typical building’s emissions.

Who could do this work? 

Benchmarking involves several tasks, including: collecting descriptive data on a building, collecting energy use/utility data, entering data into the benchmarking tool, and interpreting and reporting results. In some organizations all the work might be done by a single person, the benchmarking lead; in others the work might be divided among a benchmarking team or between departments. In many cases, the benchmarking lead will have to communicate with others to secure necessary data. For example, they might have to work with accounting staff to obtain utility bills or with the facility engineer to collect building data such as size or operational parameters. 

In cases where an third- party service provider is hired to complete benchmarking for the building, their scope of work might involve a few discrete tasks or be a full turnkey solution, including reporting for compliance. Benchmarking could be written into the scope of work of an Emissions Reduction Audit (see section 2C). A list of service providers is available here.

To benchmark GHG emissions from energy, multiply the amount of each type of energy (electricity, natural gas, fuel oil) consumed by a building by an emissions factor for that type. The emissions factor represents the amount of GHG emitted for every unit of energy consumed. Several sources have useful emissions factor data: 

• EPA GHG Emission Factors Hub: This page has PDF files with emissions factors for fuel combustion and links to some other data sources such as eGRID. 
• Emissions & Generation Resource Integrated Database (eGRID): eGRID is a database which provides emissions factors for electricity use. Since different parts of the country use power generation sources such as solar, wind, coal, nuclear, or natural gas in different amounts, eGRID gives a geographic breakdown of the emissions factors for different regions. The Summary Data and Power Profiler sections are quick ways to find an appropriate emissions factor for electricity consumption. 
• Cambium: Cambium is a dataset created from a model which forecasts future emissions from the electrical grid as renewable sources gradually account for a larger share of generation. This data is useful for predicting the emissions impact of building energy improvements into future years. Cambium’s current projections go to 2050. 

The next figure shows the expected emissions factors for the Illinois electrical grid through 2050; this information is derived from NREL’s Cambium tool Mid-case Long Run Marginal Emission Rates. These factors can be used to help estimate future emissions under possible plan scenarios. 

The Illinois grid is composed of two regions, MISO Central and PJM West. To find out which region your building is in, refer to this map.