Garland Power & Light Presentation Highlights 7/21 K.Agee

The featured speaker for WGNA’s 3^rd quarterly meeting was held 7/22/21, featuring David Koliba of GP&L.

David heads up Commercial Accounts Administration for Garland Power & Light (“GP&L”) and gave a us a very insightful presentation, including a detailed account of the 3-1/2 day period starting in Feb 14^th that included loss of power for many residents, here and across the state of Texas. Following are some highlights:

Garland Power & Light is one of 72 municipally-owned utilities within the State of Texas, and is the 4^th largest, behind San Antonio, Austin, & Lubbock. GP&L is capable of generating up to 450 Megawatt hours of power and has four generators at their Olinger Electric Plant near the south end of Lake Lavon. There are 99 “main feeder lines” running across the city, each with the ability of being cut out of the network. However, some lines are considered too critical to interrupt without a lot of pre-planning.

David pointed out that GP&L would have probably been able to supply enough power to support its customers during the critical period between Feb 14^th and Feb 18^th (including two rounds of sleet & snow and -2F degree low temps). Since GP&L (and other municipal utilities) are governed by ERCOT (“Electric Reliability Council of Texas” which manages the entire Texas electrical grid), they had to comply with ERCOT’s rules, and that’s when the problems started.

Around midnight on the 14^th, ERCOT issues their first mandate to shed some electrical loads from the grid. This EA1 (“Energy Alert level 1”) was issued once the grid’s total capacity fell below 2,300 megawatts above the demand. Under normal conditions there is about 3,000 megawatts of cushion between capacity and needs.

Several minutes after the EA1 warning, they issued EA2. That is issued whenever capacity is less than 1,750 megawatts above the needs. Then – only about 15 minutes later – they moved to the rarely used EA3 level alert. This means a crash of the grid is imminent unless more load is shed quickly! David said that ERCOT was able to avoid a collapse with only about 4 minutes to spare! Garland had some difficulties getting some of their outdoor cabinets open due to a coating of sleet, but were able to pull fuses from as many feeder-lines as needed. The specific down-time for a given neighborhood depended on which feeder-line they were connected to, or if they were lucky enough to live near one of the “protected feeders” that were never shut off (ex. near a hospital).

There were several reasons for the power grid failure, despite usage not being as high as our normal summertime usage. For starters, winter is a common time for providers to do maintenance on their generators, and reassembling them takes time. These days the Texas grid gets about 31% of its energy from wind & solar – but that’s only on a good day. The storm brought with it several cold cloudy days, with two periods of sleet & snow. The windmills in Texas typically don’t have the same de-icing features as the ones up north, so they couldn’t contribute much power, and even once the sleet & snow was cleared from the solar panels, it was either cloudy or it was dark for quite a bit of the event. Meanwhile, some of the natural gas generators failed, typically because the lines either froze or the loss of electricity made their pumps stop working.

David mentioned that the large subsidies given to renewable generation systems have made it unprofitable for new fossil fuel systems to be added to the grid. So until battery technology or other storage systems become practical, the grid will still be somewhat vulnerable to the forces of nature.