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Per-capita greenhouse gas (GHG) emissions decreased in 2020.

 

There was an approximately 21 percent decrease in per capita GHG emissions from 2018 (the last data reported by the Council) to 2020 (the most recent available data). GHG emissions in 2020 were calculated at 9.1 metric tons per capita, which was less than the calculated goal of 11.2 metric tons per capita.³

 

The largest decrease in GHG emissions generated in Connecticut* from 2018 to 2020 was in the transportation sector (16 percent). The effect of the pandemic on transportation is also evident in the amount of transportation fuel sold in the state in 2020 and the calculated daily vehicles miles traveled. The biggest monthly decline in motor fuel sales in Connecticut occurred in April 2020, which was approximately 40 percent less than the gallons of transportation fuel sold in April 2019.⁴

_{Goal: Prior to 2022, state law set three goals for greenhouse gas emissions: reduce statewide emissions to 10 percent below 1990 levels by 2020, 45 percent below 2001 levels by 2030 and 80 percent below 2001 levels by 2050. Public Act 22-5 established a new goal for the state to reduceGHG emissions to a level of zero percent from electricity supplied to electric customers in the state by 2040.} 

_{Technical Note: *Connecticut’s GHG emissions are now calculated by the Department of Energy and Environmental Protection (DEEP) using the consumption of electricity, not the generation of electricity in the state. According to DEEP’s report, Connecticut Greenhouse Gas Emissions Inventory 1990-2021, “in 2019, 2020, and 2021, in-state electric generation emitted 9.5, 10.2, and 11.0 MMTCO2e respectively. For the three years, consumption of electricity in Connecticut resulted in 5.7, 3.2, and 3.0 MMTCO2e in GHG emissions.” MMTCO2e = million metric tons of carbon dioxide equivalents. The x-axis on the chart is not to scale. The goals on the chart above have been adjusted to account for growth in population that is projected for 2030 and 2050. Values from previous reports have been updated based on more current data. **The vertical axis on the chart starts at 1.4 million rather than zero.}

 

While there was a significant decline in GHG emissions in the transportation sector from 2018 to 2020, the transportation sector still accounted for the most GHG emissions in 2020 at 40 percent, while the residential, commercial, and electric power sectors accounted for 20 percent, 12 percent, and 10 percent, respectively, based on the electric consumption model.⁵

Using the electric generation model, transportation still accounted for the most GHG emissions in 2020 at 33 percent, but the electric power sector was the second largest contributor at approximately 26 percent. (The dashed line in the chart, which represents the GHG emissions from the electric power sector using the generation model, is for illustrative purposes only.)

Greenhouse Gas Emissions from Stationary Sources Increased in 2021

Facility-level data from the Environmental Protection Agency (EPA) indicates that GHG emissions from large reporting facilities in the state increased approximately 25 percent in the last ten years. GHG emissions from reporting facilities in the “power plant” sector increased over 35 percent from 2011 to 2021. *** This is consistent with the Council’s analysis of the electricity generation data that indicates an increase in fossil fuel electricity generation.

In order to meet the GHG emissions reduction goal for 2050, significant reductions of GHG emissions in the transportation, electric power, and residential sectors, which combined made up more than 70 percent of all GHG emissions in 2020, will be needed. The needle in the chart depicts the average annual reduction (0.15 metric tons per capita) of GHG emissions for 1990-2020, using the electric consumption model. The annual per capita reduction needed to achieve the 2050 goal, based on the projected population, is approximately 0.22 metric tons.

_{Technical Note: ***The “power plant” sector made up approximately 81 percent of GHG emissions from large “reporting” facilities in Connecticut in 2021. Emissions are reported in terms of carbon dioxide equivalents (CO2e, i.e., CO2 and other gasses with equivalent climate warming impact), also referred to as greenhouse gases (GHG). While carbon dioxide is the primary GHG, emissions of other GHGs are expressed on the basis of their potential to contribute to global warming, relative to carbon dioxide’s potential.} 

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³ _{DEEP, Connecticut Greenhouse Gas Emissions Inventory 1990-2021; portal.ct.gov/-/media/DEEP/climatechange/1990-2021-GHG-Inventory/DEEP_GHG_Report_90-21_Final.pdf. DEEP, Bureau of Energy and Technology Policy, personal communication from M. Malmrose, April 24, 2023.}
⁴  _{United States Department of Transportation (US DOT), Federal Highway Administration, Office of Highway Policy Information, Motor Fuel & Highway Trust Fund; www.fhwa.dot.gov/policyinformation/motorfuelhwy_trustfund.cfm.}
⁵  _{DEEP, Connecticut Greenhouse Gas Emissions Inventory 1990-2021; portal.ct.gov/-/media/DEEP/climatechange/1990-2021-GHG-Inventory/DEEP_GHG_Report_90-21_Final.pdf. DEEP, Bureau of Energy and Technology Policy, personal communication from M. Malmrose, April 24, 2023.}
⁶  _{EPA, Facility Level Information on Greenhouse Gases Tool; ghgdata.epa.gov/ghgp/main.do Includes power plants, petroleum and natural gas systems, chemicals, waste, metals, pulp and paper, and other emissions.}