Maths could've saved Texas's power grid in 2021

DEEP MATHEMATICS

- ADRIENNE BERNHARD

TO KEEP THE STATE'S GRID RUNNING, operators at the Electric Reliability Council of Texas (ERCOT) must supply up to 75 000 megawatts of power to meet demand. But a cascade of events on 14 February 2021-rare plummeting temperatures, up to 28 cm of snowfall, thousands of people turning up their thermostats simultaneously, and power plants spontaneously going offline - meant an extended loss of power for millions of people.

Functions often fail at the edge of their range of validity, leading to so-called edge cases: a situation that occurs only at an extreme operating parameter. An edge case can be expected or unexpected. A stereo speaker might distort audio when played at maximum volume, or a website designed to handle 10 000 users might crash when 50 000 people try to log on at the same time. Quantitatively different behaviour happens at a system's boundaries, and a failure to plan for these anomalies can have devastating consequences.

‘Our all-time peak demand record is about 75 000 megawatts,’ says Joshua D Rhodes, PhD, who works in the Webber Energy Group at the University of Texas at Austin. ‘In order to keep the lights on in Texas, we would have had to push the system up to 76 000 megawatts, further than we’ve ever pushed it before.’ Professor Rhodes’s research focuses on the bulk electricity system, and the grid optimisation models he builds frequently result in edge cases. ‘I push the grid to extremes – or what I thought were extremes.’