HONG KONG—China is struggling with widespread power shortfalls, dealing a blow to the recovery of the second-largest economy and risking disruption to global supply chains and heightened inflationary pressure around the world.

The power crunch, on a scale unseen in more than a decade, highlights how some of Beijing’s changing policy priorities, including its effort to limit carbon emissions, can ripple through a global economy that has been reshaped by the pandemic.