Intermittency in Wind Energy and Emissions from the Electricity Sector: Evidence from 13 Years of Data

Dilek Uz,Callista Chim

doi:10.3390/su14042242

Abstract

Renewable subsidies and mandates currently play a central role in the environmental and energy policy in the United States, one of the world’s top greenhouse gas emitters. Therefore, accurately estimating the environmental benefits from wind energy is key to evaluating the existing policies and setting future directions and has been studied within a growing body of the literature. However, most of the existing studies do not take the intermittency into account, and the small number of studies that do only study a relatively short time period limiting the extent to which they can be informative within different ranges of wind generation capacity. In this paper, we present the first estimates of the environmental benefits of wind energy generation using a dataset that spans well over a decade. Specifically, we use 13 years of hourly and sub-hourly data to estimate the causal effect of wind generation and its intermittency on CO2, NOx, and SO2 emissions from the electricity sector in Texas. Additionally, we compared the full sample results to those from sub-samples where the dataset is divided into subgroups based on wind output level. We found that while wind generation clearly has a statistically significant negative marginal effect on all pollutants we studied, the marginal effect of intermittency varies across different wind output levels in a highly irregular way. Our findings suggest that conducting pooled analyses has the potential to mask the irregularity in the variation of the effect of intermittency in wind generation across different wind output levels.

Highlights

Wind generation capacity in the United States has grown rapidly in the past two decades due to the precipitous decline in costs as well as financial incentives and state level mandates for renewable energy playing a central role in US environmental policy [1,2].Consistently, annual electricity generation from wind energy increased from 6 billion kWh (0.1% of total) in 2000 to 338 billion kWh (8.4% of total) in 2020 in the US [3]
Since the environmental benefits are cited as the main justification for allocating public funds to incentivize renewable energy sources, accurately measuring these environmental benefits is key for evaluating existing policies as well as setting future policy directions
This paper extends the literature by significantly expanding the time period and the scope of wind generation capacities within which this subject is studied and by using more flexible functional forms in the estimation models allowing for an additional source of heterogeneity in the estimated effect

Summary

Introduction

Wind generation capacity in the United States has grown rapidly in the past two decades due to the precipitous decline in costs as well as financial incentives and state level mandates for renewable energy playing a central role in US environmental policy [1,2]. The prevailing insight from this group of studies is that while an increased level of renewable integration would reduce emissions, the magnitude of the effect depends on the existing fuel mix and technical characteristics of the system While this method is more accurate compared to using the average emissions, performing a full dynamic optimization analysis would require often hard-to-access grid dispatch models and proprietary data on transmission lines and individual generating units. Our study uses a dataset that ranges from January 2007 to December 2019, which makes it the first paper that econometrically estimates the causal effect of wind and its intermittency using sub-hourly data that spans well over a decade Throughout this period, we see a seven-fold increase in the installed wind capacity

Data and Econometric Strategy

Econometric Strategy

Results and Discussion

Conclusions