The energy sector is transforming rapidly.
Renewable, distributed energy sources like solar, wind, battery storage and small nuclear reactors will continue to change how energy enters the grid. Massive data centers are spiking demand. The electrification of transportation and industry promise to keep demand high in the coming years. By 2030, it’s estimated that electricity demand in the United States will increase 25% over 2025 levels and 78% by 2050.
While the energy industry, regulators and researchers mobilize to meet this demand, there is one literally gigantic bottleneck: the electricity grid itself.
In its current form, the grid is a massive network of generating stations, hundreds of thousands of miles of transmission lines, countless converters and local distribution systems that deliver electricity to our outlets. Despite its size and reach, the grid just isn’t capable of efficiently and cost-effectively absorbing all the new energy expected to come online in the near future.
“You hear from scientists and engineers that our grid infrastructure is old. If we want to put in more power sources for data centers or support new populations or do whatever we want to do, we need energy—and that energy will be transmitted through the grid and grid technologies,” says Mahima Gupta, the Thomas A. Lipo Assistant Professor in electrical and computer engineering at the University of Wisconsin-Madison.
Gupta studies power electronics and energy conversion technologies. She’s the principal investigator on a new U.S. Department of Energy Advanced Research Projects Agency-Energy (ARPA-E)-sponsored project aimed at more than doubling grid capacity. “We need to catch up to the current century,” she says. “We have all these new energy technologies we’re working on—but what’s the point if you can’t transmit energy efficiently?”
There are many ways to upgrade the grid, but one key solution is adding strategically placed high-voltage direct current transmission lines around the country.
Most electricity in the United States is AC, or alternating current. That’s because AC, in which the direction of the current reverses several times per second, is relatively easy to convert to higher or lower voltages—meaning high-voltage electricity in transmission lines can be stepped down for use in residential and commercial outlets. Direct current (DC), on the other hand, moves in one direction. It’s more difficult to convert—or at least it was when the grid was initially built more than 100 years ago.
DC power, however, does have advantages over AC. First, it can travel much longer distances with less electricity loss. DC transmission infrastructure requires a smaller footprint and less right of way. It’s cheaper to build than AC infrastructure and it’s better able to absorb the energy of different frequencies—for instance, energy from solar and wind installations and other grid systems.
Those qualities make DC ideal for the emerging energy economy, in which energy can be transmitted hundreds of miles—for example, from desert solar installations to distant cities. DC would also allow the eastern, western, Texas and Quebec energy grids, which currently work independently, to seamlessly connect with one another, enabling greater energy sharing. That’s especially important during widespread severe weather events like the 2021 Texas power crisis, when freezing weather led to a widespread, long-term and deadly power outage.
Industry and governments are, for the most part, on board with deploying high-voltage DC across the continent; in fact, several isolated high-voltage DC lines already exist in the United States and Canada. Still, DC voltage conversion requires expensive, bulky equipment, and using current technologies to expand the high-voltage DC grid would be prohibitively expensive.
“If the main motivation is to push the voltage levels so that you can move more power across long distances with the least losses, high-voltage DC is the natural choice,” says Gupta. “But we need to make leaps in technology so it’s ready to do that inexpensively.”
One initiative to make high-voltage DC a near-term reality is ARPA-E’s Disruptive DC Converters for Grid Resilient Infrastructure to Deliver Secure energy (DC-GRIDS) program. Its goal is to investigate new ways to bring down the initial costs of multi-terminal high-voltage direct current substations and make the technology cost-competitive with AC systems. The agency estimates a full rollout of high-voltage DC upgrades could boost grid capacity by a whopping 250%. In March 2026, DC-GRIDS announced the selection of 12 projects from across the country that will receive a total $35 million for high-voltage DC transmission research.
Gupta is the principal investigator on one of these new projects: “Multi-port iso-MMC: A converter station architecture for multi-directional power routing electric grid superhighway,” which is receiving $2.9 million from DC-GRIDS. The project also involves UW-Madison colleagues Dominic Gross, an associate professor of electrical and computer engineering; Giri Venkataramanan, the Keith and Jane Morgan Nosbusch Professor in ECE; Gregory Nellis, the William A. and Irene Ouweneel-Bascom Professor in mechanical engineering; and Allison Mahvi, the Duane and Dorothy Bluemke Assistant Professor in mechanical engineering. The project also includes collaborators from six other organizations, including researchers from Arizona State University and industry partners Siemens Energy, SNC Manufacturing, Ideal Power, Inc., Electric Power Research Institute, and Grid United. Their goal is a top-to-bottom design of a compact, super-efficient DC converter substation, including Gupta’s advanced power converter circuits, which are small, efficient and integrate new magnetics designs, control and protection systems, thermal cooling management systems and control and protection algorithms.
“You can imagine this doesn’t just involve electrical engineering, which is my expertise,” say Gupta. “We have experts from control systems, system integration, thermal management and magnetics. We are working with equipment suppliers, transmission line project developers, and experts who can help us inform future standards, because these systems don’t exist yet.”
At the conclusion of the project, in about three years, Gupta says she hopes to have an open-source, lab-validated design that could be used to produce a full-scale high-voltage DC conversion station prototype at a much lower cost.
She is also rooting for the dozen other projects funded by DC-GRIDS, not to mention other grid-modernization projects conducted by industry and other research programs throughout the world. Her hope is that this widespread, simultaneous effort will make it out of the lab and have a major real-world impact over the next two decades as an advanced high-voltage DC grid begins to take shape. “We are doing all this work, which starts from modeling and simulation to lab scale and then a full-scale prototype development so that ultimately, this technology can see the light of day and enable widespread electrification to accommodate the surging power demand,” she says.
Top image caption: Mahima Gupta is leading an ARPA-E funded project to make the electricity grid ready for high-voltage direct current transmission lines. Photo by Joel Hallberg.