Do Texans Kickstart the Weekend at 4pm on Fridays?
By: Eric Agar
Tags: Society, Energy, Texas, Friday, Electricity

Covid-19 has been a terrible disease worldwide. From the incredible illness and death toll to the economic fallout from widespread lockdowns, it would be quite difficult to find someone whose life has not been affected by the novel Coronavirus. With the lockdowns, on the other hand, there are quite a few stories about how nature has changed due to the great disruption in normal human activity. From clean air in India to wildlife thriving in the absence of humans, there have been some fascinating changes on Earth when humans worldwide have had to adjust their daily activity by great amounts.

I wrote previously about the significant decrease in U.S. air travel since the lockdowns in Spring 2020. Another area that I am fascinated about is electricity usage. When I was younger, I was a fanatic about saving energy. It felt so good to change out old incandescent light bulbs to the cutting-edge (at the time) compact fluorescent (CFL) light bulbs (today CFLs seem antiquated compared to LED lighting). I even spearheaded a campaign at my university to encourage people to use the stairs instead of elevators to save electricity (and also become healthier!).

As I have grown older, I am no longer the fanatic about saving energy as I was younger, although I am still a tree-hugger at heart. Nonetheless, the topic of energy usage is intriguing to me, especially in this Covid-19 lockdown world. Many articles have been written regarding changing patterns regarding electricity consumption throughout the world. The International Energy Agency’s (IEA) portal about the topic is great for an international summary, while the Energy Information Administration (EIA) has quite a few interesting charts focusing on American electricity patterns.

I wanted to research this topic more fully and fortunately for me, there is an unbelievable amount of public data about electricity usage on the Internet, at least for the United States. I was so pleasantly surprised at the treasure trove of data sets that actually I had trouble concentrating on what I wanted to investigate for this blog post. Yet during that euphoria, I discovered something quite interesting about electricity usage in Texas.

An Electrifying Trove of Data

I will be exploring Covid-19 electricity usage in upcoming blog posts, however as part of that research, I looked at pre-lockdown electricity usage, specifically the year 2019. The Electricity Reliability Council of Texas (ERCOT) has incredibly rich data on their website, including daily electricity demand for all of 2019. As ERCOT states they provide about 90% of Texas’ electricity usage, their data is great for looking at Texans’ electricity habits.

Using this data, I made a very simple chart in which I averaged each hour of the day’s electricity usage for the 365 days in the year 2019. The results were quite interesting to me. The first thing I noticed was that there was a clear behaviour change between the weekdays (Monday-Friday) and weekends (Saturday-Sunday) during the morning hours. The divergence starts around 4am, with weekday electricity usage increasing sharply starting around 5am-6am. Weekend electricity usage doesn’t really pick up until after 8am. Of course this makes sense; people have to get up for work on the weekdays while on the weekends they can sleep in. Yet having it so clear on the graph is quite exciting to me.

Yet it was the afternoon chart pattern that I did not expect at first glance. Starting around 2pm, Friday starts to diverge from the rest of the weekdays (Monday-Thursday) with Friday having slightly less energy usage than the other weekdays. By 4pm, there is a clear difference that Texans are using less energy usage on Fridays compared to Monday-Thursday, with the largest decrease occurring around 8pm.

This brings up observations. First, that there is a clear difference in usage patterns between Friday and the other weekdays shows that there is something different about Friday afternoons. This is especially true since Friday mornings are identical in pattern to the other weekday mornings. Second, Friday afternoons visually look more akin to Saturdays and Sundays than to the other weekends. Clearly there must be some widespread phenomenon occurring here.

Leaving Work Early on Fridays is Actually a Thing

Occam’s Razor says that in general, the simplest explanation is the better explanation. While that can be debated, for the sake of simplicity, I will assume it is true. Thus, the simplest answer for the divergence in electricity usage on Friday afternoons is that people leave work early on Fridays. Anecdotally, I am sure we all know stories of people leaving work early on Friday. Perhaps it is due to business being slow or going out of town that weekend. Whatever the reason, we can point to examples where it has occurred to people we know or to ourselves. We also can point to the many social events that occur Friday nights, such as parties, concerts, or simply having dinner in a restaurant compared to at home.

More formally, there is data that suggest this is true. A 2017 study analysing energy usage patterns in the United Kingdom theorized that Fridays were associated with more social events due to four factors:

Study respondents reported they spent the least amount of time preparing food Friday evenings compared to other weekday evenings

Respondents reported they used computers the least amount of time on Friday evenings compared to other weekdays

Study respondents also stated they watched TV the least amount of time on Friday evenings compared to other weekday evenings

On the contrary, respondents noted they spent more time washing/bathing Friday evenings than other weekdays

The study’s authors opine that this is due to the “greater volume of social events” that occur on Friday evenings. People spend less time preparing food as they are eating out. No need to watch TV or use the computer as people are socializing outside the home. Finally, people want to look sharp for their night on the town; hence, the increase in washing/bathing Friday evenings.

Furthermore, the EIA writes that U.S. electricity consumption decreases on the weekends as “many commercial offices are closed and less electricity is required for lighting and computer equipment.” As I noted previously in this article, the electricity consumption curve on Friday afternoons and evenings is more akin to weekends than the other weekdays. In fact, looking at the chart even further in detail, I note that the curve for Friday evenings is more similar to Saturday evenings, while Sunday evening’s curve is more similar to Monday-Thursday. This again makes intuitive sense: Sunday-Thursday people have to get ready for work and school the next day, while Friday and Saturday evenings they can relax.

Conclusion

Something happens Friday evenings that does not occur during Monday through Thursday evenings. Either way, the data set is robust both in number of data points — 365 days in 2019 — and size — around 90% of the electrical usage in Texas, the second largest state population-wise in the United States — to show that people behave different Friday evenings than they do Monday-Thursday.

While all of this does not prove that the drop in electricity usage is due to commercial offices being closed (correlation does not mean causation), we can postulate that the two phenomena — workers going home early and the decrease in electrical consumption — are at some level tied together. This is especially true since Friday’s electrical demand starts to diverge from Monday-Thursday around 2pm and is really noticeable by around 4pm. As this is still during “normal business hours,” I believe that there is a connection between the decreased electrical consumption on Friday afternoons and evenings and workers leaving work early.

Source

Chart data sourced from electrical load data from the Electricity Reliability Council of Texas (ERCOT): http://www.ercot.com/gridinfo/load/load_hist