As the US scrambles to add power generation, efficiency experts say variable frequency drives on electric motors could cut demand sharply and ease grid constraints.
The race to add new power plants in the United States is accelerating, propelled by worries about electricity shortages and by soaring demand from electrification and data-hungry technologies. Federal programs and private capital are flowing to a wide range of generation projects, from natural-gas turbines to lower-carbon options such as solar and geothermal. But energy analysts say a substantial tranche of capacity could be unlocked without building a single new plant—by cutting waste from one of the grid’s most common workhorses: electric motors.
Roughly 50 million motors power the fans, pumps, and compressors embedded in factories, commercial buildings, and industrial sites across the country. Collectively, they consume nearly one-third of U.S. electricity demand. The problem, efficiency experts argue, is not that motors are inherently inefficient, but that many are operated in blunt, all-or-nothing ways. Systems often run at full speed even when the work being done—moving air, circulating fluids, compressing gases—requires far less output for long stretches of the day.
A prime example is a typical office building after hours. Occupancy drops, and heating, ventilation, and air-conditioning loads fall. Buildings frequently reduce airflow using dampers and valves, yet the motors and fans behind the scenes may continue spinning near maximum speed, burning electricity while delivering throttled performance. That mismatch is widespread in industry as well, where process needs vary by shift, season, or production line.
A technology known as a variable frequency drive (VFD)—also called an adjustable speed drive—targets this exact inefficiency. VFDs are electronic controllers, typically equipped with sensors such as temperature monitoring, that continuously tune a motor’s speed to match real-time demand. By letting motors ramp up and down instead of operating at a constant full tilt, the devices can dramatically reduce energy use. Neal Elliott, director emeritus at the American Council for an Energy-Efficient Economy, estimates VFDs can cut a motor’s electricity consumption by about 40% to 60%, depending on the application.
Despite the potential, VFDs remain underused. A 2021 market assessment from Lawrence Berkeley National Laboratory found that only about 16% of motor systems in industrial facilities employ VFDs, and the share is even smaller—around 4%—for motors in the commercial sector. Industry observers attribute the slow uptake to the perceived inconvenience of retrofitting existing equipment and the fact that VFDs are often not mandated by codes or standards.
Now, proponents say, the case for broader adoption is getting stronger. Reducing motor demand would effectively “free up” capacity on constrained grids for fast-growing loads like data centers and electric vehicles. It could also lower operating costs for manufacturers that are replacing fossil-fueled heating with electric technologies—such as heat pumps—that rely heavily on motors, at a moment when industrial electricity prices are rising quickly. Meanwhile, VFDs themselves have advanced, becoming more capable and less costly to deploy than earlier generations. “This is low-hanging fruit that gives a lot [of energy] back and is reasonably simple,” said Nik Sawe, a senior policy analyst at the think tank Energy Innovation.
Real-world economics can be compelling. Toyota, for instance, outfitted more than 200 motors in the HVAC system at its Georgetown, Kentucky auto plant with VFDs as part of a 700,000 and has continued using the approach at other U.S. facilities.
Elliott argues the concept is hardly new—engineers have long recognized that matching motor speed to the task can deliver major efficiency gains. What may be changing is the urgency, as grid constraints and electrification pressures turn a once-niche retrofit into a broader opportunity for policymakers, utilities, and large electricity users.
Why it matters
If widely deployed, VFDs could reduce electricity bills for businesses while easing strain on regional grids—potentially delaying or shrinking the need for new power plants. The main beneficiaries would be industrial sites and commercial buildings with variable loads, as well as communities facing capacity bottlenecks. Watch next for new utility incentive programs and federal efficiency standards that could push adoption beyond today’s low penetration rates.