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PNNL Uses Granular Load Data To Shed More Light On COVID-19 Impacts

A new study by researchers at the Pacific Northwest National Laboratory (PNNL) uses a more granular examination of usage data to analyze the impact of COVID-19 on electricity use to shed light on the driving factors behind those changes.

A lot of research on electricity use focuses on either the micro or macro level. The PNNL paper, Multiscale effects masked the impact of the COVID-19 pandemic on electricity demand in the United States, used three data sets: two from the Energy Information Administration (EIA) – EIA-930 that looks at hourly load profiles at the balancing authority level, and EIA-861M that looks at state level monthly electricity sales – and anonymized electricity usage data available from Commonwealth Edison for a fee that provides usage data by zip code and 15 different customer classes.

“We found a gap in research where people hadn’t gotten data at the right scales to understand the underlying drivers,” Nathalie Voisin, a PNNL earth scientist and co-author of the study, said in an article on PNNL’s website by Beth Mundy, a PNNL communications professional.

The resulting analysis showed that the effects of the COVID-19 pandemic first appeared in the spring of 2020 and persisted at least through the fall of 2020.

More specifically, the researchers found that the impact of COVID-19 was dampened across all three data sets because changes in residential loads and non-residential loads had a similar magnitude but moved in opposite directions.

Weekday residential load profiles in April 2020 resembled weekend residential load profiles in April 2018 and 2019, a transition to “perpetual weekend” that was also observed in the New York Independent System Operator, the researchers said.

“Before the COVID-19 shutdown,” the paper noted, “weekday residential evening ramps were commonly greater than +1,000 MW in a 3-hour period in February 2020. After 16-March weekday residential load profiles had ramps that were half as steep. Total April 2020 weekday electricity consumption for non-residential customers was 16% lower than in April 2019 while consumption for residential customers was 12% higher.”

“This may be due in part to year-to-year changes in weather, but the changes in the shape of the load profiles are more consistent with impacts of the shelter-in-place order,” the researchers said.

The researchers also found that demand for electricity during the summer of 2020 “became more strongly dependent on diurnal temperature variations and less dependent on inhabitance schedules,” which acted to reduce the impact of more people staying home during the day. That pattern was “clearly evident in the spring and then re-emerged in the fall of 2020,” the researchers said in the paper.

The “COVID-19 signal” was also masked at the balancing authority level by the phased reopening and spatial variability in reopening during the summer of 2020, the researchers said. “Breaking the data down into smaller zones within the balancing authority showed that the impact of COVID-19 persisted through the summer and into the fall of 2020,” they said.

Some of the trends identified in the paper would not have shown up as clearly if only aggregated total load data were used, the researchers said. The use of a longer record of granular electricity consumption data helped to isolate changes attributable to natural year-to-year changes driven by weather variability from changes due solely to the pandemic, they said.

Use of more granular data would also allow analysis of how the pandemic response in different regions resulted in changes to electricity consumption, they said.

And while more granular load forecasting models are emerging, “more widespread analyses of the type presented here are needed to inform system operators and utilities for long-term resource planning,” the authors said in the paper.

The trends noted in the paper could persist if a higher proportion of people continue to telecommute indefinitely, “although the magnitude is dependent on factors that are highly uncertain,” the researchers said.

In terms of implications, a shift toward a higher residential portion of total load could make residential rooftop solar “slightly more favorable,” the researchers said, adding that a midday increase in residential loads could increase the rates of self-consumption of solar power rather than exporting it to the grid, reducing challenges in integrating residential solar power.