Note: This page was created in August 2022 with the static manufacturing Carbon Sankey diagrams. Static energy Sankey diagrams for 2018 and previous iterations are also available.

The U.S. Manufacturing Static Carbon Sankey diagrams illustrate the flow of greenhouse gas emissions by U.S. manufacturing plants, based on EIA MECS data for 2018 and the EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks (1990-2019).

Preview of the 2018 Carbon Sankey diagram, which shows the flow of greenhouse gas emissions in key U.S. manufacturing sectors.

The Carbon Sankey diagrams show the greenhouse gas (GHG) emissions generated from the consumption of fuel, steam, and electricity entering U.S. manufacturing plants from offsite sources. Offsite energy is used directly for onsite energy generation, production (process energy), or supporting functions (non-process energy). Both combustion and process emissions associated with the direct use of offsite energy supply are shown. Emissions are estimated by applying emission factors from EPA’s Mandatory Greenhouse Gas Reporting Rule to the components of offsite energy consumption. Emissions are reported in carbon dioxide equivalents (CO2e). For more information on GHG analysis, please see Understanding the 2018 Manufacturing Energy and Carbon Footprints and 2018 Carbon Footprint Analysis Definitions and Assumptions.

These diagrams visually complement the 2018 MECS Manufacturing Energy and Carbon Footprint analysis. Definitions of terms used in this Sankey diagram are at the bottom of this page.


Static Carbon Sankey diagrams are available for six manufacturing sectors and U.S. manufacturing as a whole. Each of the Sankey diagrams are accessible through the links below.


Carbon dioxide equivalent (CO2e) – A measure used to compare the emissions of various greenhouse gases, such as CH4 and N2O, based upon their global warming potential (GWP).  The functionally equivalent amount or concentration of CO2 serves as the reference. CO2e is derived by multiplying the mass of the gas by its associated GWP, with units commonly expressed as million metric tons of carbon dioxide equivalent (MMT CO2e).

Greenhouse gas (GHG) combustion emissions – For this analysis, the emissions considered from the fuel use of energy include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as these are the greenhouse gases released during the combustion of fuel. Over 99% of the emissions from combustion are CO2. While CH4 and N2O contribute only a small amount to total emissions, they were included in this analysis to best adhere to the EPA reporting rule.

Nonprocess Energy: Energy used for purposes other than converting raw material into manufactured product. MECS-specified categories of nonprocess energy include facility heating, ventilation, and air conditioning (HVAC), facility lighting, onsite transportation, other facility support (e.g., cooking, water heating, office equipment), and other nonprocess use.

Offsite Electricity Generation (net): The sum of purchased electricity and electricity transfers into the plant boundary (including electricity generated onsite from non-combustion renewable resources to align with MECS Table 5.2 values), less quantities sold and transferred out. This value does not include onsite generation from combustible fuels or onsite cogeneration which are all accounted for by the “other electricity generation” and “CHP/cogeneration” values.

Offsite Fuel: The sum of purchased fuel, fuel transferred into the plant boundary, and byproduct fuel (from externally sourced feedstocks or nonenergy inputs) produced and consumed onsite.

Offsite GHG combustion emissions – The emissions released by the fuel use of energy (i.e., combustion) outside an industrial facility, but associated with energy later consumed by the facility. For example, a power plant generates electricity by burning coal as fuel. An industrial facility then purchases this electricity and consumes it at its facility. The offsite emissions associated with this electricity use are those that were released during the combustion of coal at the power plant while generating that electricity. Similarly, emissions are released during the generation of steam offsite. The offsite GHG combustion emissions in the footprints diagrams account for the sectors scope 2 emissions.

Offsite Steam Generation (net): The sum of steam transfers and purchased steam from the local utility or other sources, less quantities sold and transferred out.

Onsite GHG combustion emissions – The emissions released by the fuel use of energy (i.e., combustion) within the industrial plant boundary. This fuel is used “indirectly,” to generate steam and electricity for later use, and “directly,” to power processes and supporting equipment. In the footprint diagram, the emissions from indirect end uses, namely onsite steam and power generation, are not distributed to the direct end uses of that energy. For example, process heating onsite emissions do not include the emissions released during onsite generation of steam used for process heating. GHG combustion emissions generated from onsite generation, process energy, and nonprocess energy contribute to the sector’s scope 1 emissions.

Emissions from the combustion of blast furnace gas, coke, and coke oven gas are considered process emissions and are thus not considered combustion emissions, in accordance with EPA and Intergovernmental Panel on Climate Change (IPCC) guidelines. Also excluded are CO2 emissions from biomass use.

Onsite Generation: The generation of steam or electricity within the plant boundaries using fuel or electricity. Onsite generation includes three categories: “conventional boilers” (to produce steam), “CHP/cogeneration” (to produce steam and electricity), and “other electricity generation” (consisting of onsite electricity obtained from generators running on combustible energy sources including natural gas, fuel oils, and coal).

Process Energy: Energy used in industry-specific processes, such as chemical reactors, steel furnaces, glass melters, casting, concentrators, distillation columns, etc. MECS-specified categories of process energy include process heating (e.g., kilns, ovens, furnaces, strip heaters), process cooling and refrigeration, machine drive (e.g., motors, pumps associated with process equipment), electro-chemical processes (e.g., reduction process), and other direct process uses.

Process Emissions – The emissions generated and emitted as byproducts of various non-energy-related industrial processes and not directly a result of energy consumed during the process. For example, raw materials can be chemically or physically transformed from one state to another. This transformation can result in the release of GHGs and would be consider a process emission. Process emissions data was sourced from EPA’s Inventory of U.S. Greenhouse Gas Emissions and Sinks, Chapter 4: Industrial Processes and Product Use Emissions.  Process emissions generated from process energy contribute to the sector’s scope 1 emissions.


  1. The data source for this Sankey Diagram is the 2018 MECS Manufacturing Energy and Carbon Footprint. The footprint analysis utilizes 2018 EIA Manufacturing Energy Consumption Survey (MECS) data, with adjustments, to quantify steam generation, electricity generation, and incoming fuel; onsite steam and electricity generation; and end use of electricity and fuel. Steam end use is not provided by MECS but rather is dependent on analysis alone.
  2. Fuel-specific emission factors are sourced from EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks.
  3. Offsite electricity emission factor is sourced from EPA eGRID.
  4. Emissions values represent aggregate sector-wide data for 2018 in CO2e, rounded to the nearest tenth.
  5. Excludes feedstock energy (byproduct fuels from feedstock are included).
  6. Arrow and box heights are proportional to flow size except for small flows for visual convenience.