PITTSBURGH — The challenges of climate policy and disruptive technologies that cloud the grid’s future look like opportunities to some of the engineering students who hope to manage that future.
A power industry conference last month at the University of Pittsburgh’s Swanson School of Engineering was a platform for students to describe research projects on renewable power generation, semiconductor electronics, direct-current power lines, battery storage and electric vehicle charging.
U.S. EPA’s Clean Power Plan and the climate change threat it addresses have caused deep political divisions around the country. But the agendas of these students, their professors and the companies that support their work amount to a big bet on the inevitable transformation of power grids, however the immediate politics work out.
Stephanie Cortes, a Swanson senior from Florida, is working on bidirectional power control systems to automate when electric vehicle owners recharge their cars, and when they return excess power to the grid. The goal, she said, is "to reduce grid impacts, increase confidence in the system and facilitate integration of EVs" into power networks.
Alvaro Cardoza, a graduate student from the Pittsburgh area, is aiming at technologies that will manage more variable wind and solar power without stressing grid reliability. "I think there will be definitely an increase in renewable generation, as well as a more distributed nature of the generation. In 10 years’ time, if we were to use the same technologies we’re using now, it would lead to a lot of instability in the grid," Cardoza said. "It would basically shut down the grid."
Another graduate student, Joseph Kozak, from the Philadelphia area, partners with Cardoza and his team to develop next-generation, wide-bandgap semiconductors from gallium nitride rather than silicon, enabling grid electronic devices to run at much higher voltages and temperatures than today’s devices.
The potential uses of this "game changing" technology include applications for grid transformers and plug-in electric vehicles. "I am focused on how to make these kinds of power devices a lot smaller, a lot lighter, hopefully cheaper, and more resilient in different ways," Kozak said.
Ansel Barchowsky, a doctoral candidate from New Hampshire, is seeking to reduce the size and cost, and increase the efficiency, of devices that step up the voltages of direct-current flows. "A lot of research is going into making semiconductor devices that produce higher and higher voltages. What we’re working on is building modular converters" by stacking gallium nitride devices into a column, he said. "So instead of having one big voltage step, we have many little chunks of voltage that can build up to form our output."
"We’re trying to achieve converter outputs that are two to three times [current levels]," he said. "And you can hold them in the palm of your hand." With such advances, homes can have DC circuits, connecting rooftop solar units to basement batteries, to charge home electronics. "In 10 years, 15 years, there are going to be power conversion systems everywhere," Barchowsky said.
A new ‘Battle of the Currents’
The featured speaker at the university’s 10th annual Electric Power Industry Conference was historian Jill Jonnes, who gave a reprise of her book "Empires of Light," an account of the "Battle of the Currents" at the end of the 1800s.
This was the pitched fight to decide whether the United States would be wired for direct current — Thomas Edison’s choice — or alternating current, backed by Nikola Tesla and Pittsburgh magnate George Westinghouse. Edison tarnished his reputation with a below-the-belt attack on AC’s dangers, she recounted. But AC prevailed. Transformers could step AC voltages up, enabling long-distance transmission. And Tesla provided a practical, durable electric motor that could run on AC.
A new future for direct current is a primary goal for the Swanson School’s faculty and students, who have the opportunity that Edison never saw to use semiconductor electronics to make DC act like AC.
"It’s interesting why Edison happened to lose that particular battle — because he didn’t have a transformer. He didn’t have anything to be able change voltages," Barchowsky said. The inability to transmit direct current beyond short distances forced Edison into a strategy of "distributed" power plants throughout a city. "It’s funny that we’re trending back toward that world" with microgrids, Bachowsky said.
The Swanson School’s interest in DC owes much to the support of key businesses and foundations in the city, and a desire to leverage DC technology leadership into a stronger economic foundation for the city, says Gregory Reed, director of the Swanson School’s Center for Energy.
Eaton Corp., Mitsubishi Electric, Universal Electric Corp., Pitt Ohio and Duquesne Light are five of those companies that support the engineering program with research contracts on DC applications, and in some cases with internships for students, Reed said.
Their involvement in turn has led Pittsburgh’s Henry L. Hillman Foundation to invest nearly $3 million in the Swanson DC development program.
"They see it as a great opportunity for the Pittsburgh region to take technology leadership in this area and help to create economic development and job growth," Reed said. "The more we can do in the lab, and with demonstrations, partnering with industry, and the more we can help develop technologies and commercialize them, the more local companies can look at these technologies and grow their portfolios and continue to accelerate what we’re doing here. That helps make Pittsburgh a leading place for all of this."
Betting on DC’s future
Hitching a new engineering career to the future of direct current in the United States looks like a gamble, particularly for high-profile transmission projects that would upset the competitive status quo in energy markets. Houston-based Clean Line Energy Partners has spent five years trying to win state regulatory approval for its proposed Grain Belt Express, a high-voltage DC line that would deliver 4,000 megawatts of wind power from western Kansas to Missouri, Illinois, Indiana and other states. Illinois said yes last month, but Missouri said no in July. The line’s developers now hope for a 2020 or 2021 completion (EnergyWire, Nov. 15).
The pioneering Tres Amigas "superstation" HVDC project in New Mexico, proposed in 2009 to connect the Eastern and Western Interconnection grids with the Texas’ grid, only recently won approval for one leg, from New Mexico to California. However, its proposed partner linking to the Eastern grid dropped out this fall. "We took too long," a Tres Amigas official explained, according to news reports (EnergyWire, March 24).
Reed said the DC program is not risky for the students. "What they’re learning here isn’t solely about DC. They are learning the entirety of electric power technology," he added.
He acknowledged, "There is a lot of resistance to change from the long-standing AC world, just like there is from the long-standing fossil fuel world. Despite all that, technology can overcome those roadblocks," he added.
"If you look at the growth potential of DC, it’s there. It might be where solar was 10 years ago. It was slow. It had its critics. It was having a trouble getting its foothold." But solar power’s costs kept falling, Reed added. "You get to a point where the benefits begin to outweigh all of the barriers, and you see the exponential growth. It’s already beginning to happen" for direct current, he said.
"We do need to have better cooperation," he said, mentioning the need for consensus on technical standards for DC applications. "Standards in today’s world can take as long as 10 years to get put into place. That’s not an acceptable solution."
Kozak said he accepts the uncertainties in his research. "Right now, I think there is a lot that is in transition, and we don’t know what will really come out," he said. Advances in gallium nitride applications continue, and the technology could reach a turning point in a few years. Time will tell, Kozak said.
Barshowsky said the power sector he studies "is not the most agile of industries." And that’s understandable, he added: "You have a breaker from the 1950s that will still work perfectly. Why change it when it works?"
But DC devices are expanding everywhere, and they can be better solutions to help bring electricity to the developing world, he added. "We’re going to need to find more efficient ways to do some of the things that we know will work," Barchowsky said.
Cardoza said that while technology pushes change on its own, policy needs to change, too. "I think climate emissions should be addressed," he said. "We should be focused on that, and that should be one of the reasons these technologies become distributed throughout the system, because if we don’t, we’re going to be in a lot of trouble."