When a late July heat wave knocked two supposedly reliable baseload coal stations out of service in Alberta, it added another hit of reality to counter the argument that power grids need at least some big, always-on generating stations—implicitly fossil stations—to deliver consistent service, the Pembina Institute reports.
Over the course of Wednesday, July 26, as temperatures soared and air conditioners were switched on across the province, the province’s power demand spiked to 10,000 megawatts. But high ambient temperatures can affect thermal power plants’ cooling systems. “At 2 p.m., the Keephills 2 coal plant tripped offline,” Pembina recalls, and a second plant tripped at 3:45 p.m. “All told, by 4 p.m., roughly 2000 MW of coal was offline—almost a third of the installed coal capacity in the province.”
Alberta’s system operator got through the crisis by issuing emergency calls for large consumers to voluntarily reduce their power use. But as Pembina notes, the outsize impact of two plant failures highlights the fallacy in the assertion that big, central fossil generation is necessary to supply baseload reliability.
“What happened [on July 26] is a stark reminder that baseload isn’t synonymous with reliability,” write clean energy specialist Sarah Hastings-Simon and electricity program director Binnu Jeyakumar in a Pembina blog post. “It’s a lot more complicated than that.”
The blog debunks more than a dozen widely circulated myths often deployed to defend big fossil-fired generating stations. Most leverage the underlying belief that “variability means renewables are unreliable.” In fact, as the analysis shows, “renewable variability is predictable and can contribute to reliability.”
“If Alberta had significant solar [photovoltaic] generation installed,” Hastings-Simon and Jeyakumar write, “this emergency could have been avoided completely. Instead of depending on the coal plants that tripped offline, the same amount of solar capacity in Alberta would have generated enough electricity to avoid any emergency alert and the threat of blackout, while keeping prices under control. For similar energy emergencies caused by high temperatures, solar—which generates most when the sun is shining brightly—is a reliable source of power.”
Pembina’s analysis adds to the evidence suggesting that the day of big power utility assets is drawing to a close. As we reported recently on The Mix, utilities betting on capital-intensive, long-term investments are battling rising costs, delivery delays, and public resistance.