Analyzing variability and decomposing electricity emission factors for three U.S. states

Abstract

Electricity generation emission factors (EGEF) quantify the relationship between an emitted pollutant and the amount of electricity generated. Quantifying the variability among calculated EGEF is important when EGEFs are used to inform decision-making for environmental sustainability.First, variabilities in EGEF due to variability in the amount of coal, natural gas, and petroleum emissions within the fuel mix are quantified for California, Texas, and New York in 2017. The results show a higher coefficient of variation for SO2 and NOx compared to CO2 EGEF.Next, changes in the EGEF over time are studied using decomposition analysis for California, Texas, and New York from 1990 to 2017. The results show that the main factor in reducing EGEF in California is the improvement in the generation efficiency of power plants; in Texas, it is the increase in the ratio of renewable to non-renewable electricity generation; and in New York, it is the change in the mix of fossil fuels that are consumed for electricity generation.Finally, the effect of variability of EGEF on environmental impact categories is analyzed. Eutrophication of air, eutrophication of water, and smog formation are subject to high uncertainty because SO2 and NOx EGEFs are used to quantify these impacts, whereas global warming potential has less uncertainty because it only uses CO2 EGEF.

Sizing Optimization of District Energy Systems Considering Meteorological, Demand, and Electricity Emission Factor Uncertainties

“…First, uncertainties associated with CO 2 EGEF values due to variability in fossil fuel sources' emissions to generate electricity are considered. An uncertainty analysis method is used from a previous paper submitted for publication by the authors [22] to consider uncertainties due to variability in emissions of fossil fuel sources to generate electricity. In this method, Utah's EGEF is quantified using a weighted sum of the fossil fuel emissions for Utah's fuel mix.…”