The U.S. has a dynamic electricity mix, with a range of energy sources generating electricity at different times of the day.
At all times, the amount of electricity generated must match demand in order to keep the power grid in balance, which leads to cyclical patterns in daily and weekly electricity generation.
The graphic below, via Visual Capitalist's Govind Bhutada and Sabrina Lam, tracks hourly changes in U.S. electricity generation over one week, based on data from the U.S. Energy Information Administration (EIA).
Before diving in, it’s important to distinguish between the three main types of power plants in the U.S. electricity mix:
With that context, the table below provides an overview of average hourly electricity generation by source for the week of March 7–March 14, 2023, in the Eastern Time Zone.
It’s worth noting that while this is representative of a typical week of electricity generation, these patterns can change with seasons. For example, in the month of June, electricity demand usually peaks around 5 PM, when solar generation is still high, unlike in March.
Natural gas is the country’s largest source of electricity, with gas-fired plants generating an average of 176,000 MWh of electricity per hour throughout the week outlined above. The dispatchable nature of natural gas is evident in the chart, with gas-fired generation falling in the wee hours and rising during business hours.
Meanwhile, nuclear electricity generation remains steady throughout the given days and week, ranging between 80,000–85,000 MWh per hour. Nuclear plants are designed to operate for long durations (1.5 to 2 years) before refueling and require less maintenance, allowing them to provide reliable baseload energy.
On the other hand, wind and solar generation tend to see large fluctuations throughout the week. For example, during the week of March 07–14, wind generation ranged between 26,875 MWh and 77,185 MWh per hour, based on wind speeds. Solar generation had stronger extremes, often reaching zero or net-negative at night and rising to over 40,000 MWh in the afternoon.
Because wind and solar are often variable and location-specific, integrating them into the grid can pose challenges for grid operators, who rely on forecasts to keep electricity supply and demand in balance. So, what are some ways to solve these problems?
As more renewable capacity is deployed, here are three ways to make the transition smoother.