Erasing Millions of Carbon Footprints

Distinguished University Professor of Electrical Engineering B. Jayant “Jay” Baliga is leaving a huge mark on the world through the tiniest of footprints. His energy-saving inventions have left him with what many consider to be the world’s smallest carbon footprint—the amount of carbon dioxide and other greenhouse gases emitted by a person’s activity each year.

The energy savings from Dr. Jay Baliga’s inventions offsets the carbon dioxide emissions of about 31.8 million Americans each year.

Baliga launched a revolution in efficient energy use in 1980 with the invention of the insulated-gate bipolar transistor (IGBT), a semiconductor that controls the flow of power in consumer, industrial, and transportation applications. Reducing energy losses by incorporating high-speed switching, the IGBT improves energy efficiency by more than 40 percent in products from cars to appliances to light bulbs and heat pumps. The savings each year through the use of IGBTs in electric motors and compact fluorescent light bulbs alone equals more than 500 billion kilowatt-hours, which amounts to cutting annual carbon dioxide emissions by more than 1 trillion pounds.

More recently, Baliga invented power semiconductors for use in cell phone towers and laptop computers. Like the IGBT, the more efficient devices save tremendous amounts of power and further cut carbon dioxide emissions. Considering that the average American has a footprint of 44,000 pounds of carbon dioxide annually, the energy savings from Baliga’s work offsets the impact of about 31.8 million Americans—more than 10 percent of the nation—every year. Saving all those kilowatt-hours also means utilities and their customers don’t have to spend $2 billion for each coal-fired power plant required to meet higher demand for electricity. “I don’t like the term ‘smallest carbon footprint’ because it suggests I have one,” he says with a laugh. “I think of it as an enormous negative footprint.”

Baliga’s carbon offset number could soon increase again as another of his inventions, a silicon carbide semiconductor that is hundreds of times more efficient than the IGBT, is beginning to appear in consumer products. Intellectual curiosity prompted him to predict decades ago that such devices would eventually improve upon silicon transistors. But he says he was often derided as “Chicken Little” because no one saw the need to improve electrical efficiency. “It’s satisfying that the world has finally come around to appreciate the benefits of decreased greenhouse gas emissions and increased efficiency,” he says.

The next generation of improvements will come from silicon carbide and gallium nitride devices, known as wide bandgap semiconductors, Baliga says. In theory, these devices can handle high-power applications like hybrid cars and the electrical grid with a reduction in power loss of up to 100 times that of silicon IGBTs. “People around the world are not going to stop turning on the light or using a clothes dryer to save energy,” he says. “By continually improving efficiency, we can engineer sustainable solutions.”


Dr. B. Jayant “Jay” Baliga owns 120 patents on devices that improve the efficiency of electrical and electronic products, from motors and appliances to computers and cell phones.

The insulated-gate bipolar transistors that comprise the semiconductor wafer below were Baliga’s first breakthrough in conserving electricity.