How Variable Frequency Drives Unlock Hidden Grid Power

This article was originally published by Canary Media.

America’s energy supply crunch is driving a surge of federal and private investment in new electricity generation — from polluting gas turbines to cleaner developments like solar farms and geothermal plants. But gigawatts of power are already available for the taking across the U.S. economy in the form of wasted energy from an unexpected source: motors.

Some 50 million electric motors drive the fans, pumps, and compressors found in virtually every factory and building. Together, they gobble enough electricity to equal nearly a third of total U.S. power demand. Often, the motors use far more energy than they actually need to keep America’s machines humming.

Companies can install devices known as variable frequency drives, or VFDs, to make motors run super efficiently. Yet adoption remains relatively low, in part because of the perceived hassle of retrofitting equipment and because they’re typically not required. On average, only 16 percent of motor systems at industrial facilities and 4 percent of commercial-sector motors use VFDs, according to a 2021 market report by Lawrence Berkeley National Laboratory.

However, there are now more reasons than ever to equip the nation’s motors with power-saving devices, energy experts and device manufacturers say. They’re urging federal agencies, utilities, and deep-pocked tech giants to spur a wider rollout of VFDs through financial incentives and efficiency standards.

For one, slashing motors’ power use would free up grid capacity for large electricity users like data centers and electric vehicles, they argue. It would help curb costs for factories that are switching from fossil-fueled heating systems to electrified, motor-based solutions like heat pumps — all at a time when industrial power prices are climbing fast. Plus, VFD technology has become far more sophisticated and less expensive to install than earlier iterations.

“This is low-hanging fruit that gives a lot [of energy] back and is reasonably simple,” Nik Sawe, a senior policy analyst at the nonpartisan think tank Energy Innovation, says of the technology.

What are variable frequency drives?

Energy-wise, the main problem with electric motors is that they’re always running at full capacity. Consider an office building, which empties out in the evening. The heating, ventilation, and air-conditioning system can wind down in those hours, with dampers and valves restricting the flow of cold or hot air. But the motors and fans that drive the whole setup are still working in the background, wasting energy.

VFD technology, such as the Danfoss iC7 series has gained some momentum in recent years among factories and buildings trying to combat rising electricity costs. Danfoss Drives

VFDs are electronic controllers with temperature sensors that continually adjust the speed of motors, automatically ramping up or down to match demand. The technology, which is also called adjustable…