The Southwest Power Pool (SPP), the regional transmission organization that operates the electric grid for most of the central United States, has set records for the highest proportion of electricity demand supplied by wind power in both a single-hour period (72%) and a full day (62%).
In 2019, wind power supplied 29 percent of SPP’s demand for electricity. The share of total demand for wind power in 2019 ranged from a high of 37 percent in October to a low of 18 percent in August on a monthly basis. However, on a daily or hourly basis, due to variations in wind production and overall electricity generation, the proportion of wind may be greater.
System operators like SPP are responsible for balancing the supply and demand for electricity in real time. SPP primarily uses its own energy generating services to meet demand in order to preserve this balance, and participates in small energy exchange with neighboring network operators for economic or reliability purposes.
In 2019, net electricity exchange (electricity imports or exports from the region) for SPP averaged around 2 percent of generation.
Wind penetration records are frequently broken in the spring due to seasonal patterns in both electricity demand and wind power output. In the SPP region, wind generation in the spring months is often the strongest.
Spring is also a time of year when the demand for energy is fairly low, because mild temperatures mean less power is used for heating or cooling homes. Electricity demand on weekends is also comparatively smaller, when wind set its latest record share in SPP.
Wind generation follows daily patterns in addition to the seasonal patterns. The generation of land-based wind is greatest overnight, when there are typically stronger winds. Consequently, wind power records appear to be set in the early morning hours.
SPP has invested heavily in developing new wind capacity to leverage desirable wind energy.
According to data from the U.S. Energy Information Administration (EIA) utility-scale power plant inventory, as of March 2020, SPP had 21 gigawatts of nameplate wind generating capacity, representing 24 percent of total SPP generating capacity and 20 percent of total utility-scale wind generating capacity in the United States.
Those wind reports are based on data from the EIA’s Hourly Electric Grid Monitor, which offers up-to-the-hour information on the demand for and exchange of power across the U.S. grid.
While EIA has no data on hours or days that could have had a higher share of wind generation before 2018 when EIA began collecting data for the Hourly Electric Grid Monitor, wind capacity growth over the past few years makes it unlikely that a higher share has been generated in earlier years.