Despite the recent efforts for energy independence, modern energy needs are growing steadily. Viable options moving forward are reduced consumption and and more efficient means of delivering energy. In light of this, the University has taken a leading role in researching how to balance an increased energy demand with a more efficient means of delivery through so-called “smart” grids.
The smart grid is a recent development in electrical engineering, which increases current distribution efficiency compared to traditional electric grids. However, with new technology comes the need for new material. Jay Narayan, John C. Fan Distinguished Chair Professor of Material Science Engineering, has led a team of researchers for the past decade to into the process of developing a way to “integrate” gallium nitride (GaN) onto silicon chips for the use of smart grids and other technologies. GaN is a substance that can handle high voltage and current.
“This is an exciting material, which is needed for these high power devices directly,” Dr. Narayan said. “So you can make these smart grids, which are electric grids married with a computer chip. So you can transmit power more efficiently. If there is trouble, you can sense and manipulate it, since it is on a chip. The smartness means there is something you can sense, manipulate, and respond.”
Smart grids are remarkable for being able to detect levels of demand for generated current and adjust distribution accordingly, according to Narayan.
“For example, suppose parts of the region are not using or expending much energy. This grid will automatically divert energy to places where it’s needed the most,” Narayan said. “This is extremely valuable to sources of energy that can’t be stored well, like solar. If you have a solar farm, you can’t store that energy for very long. Batteries have limited capacity. So in a smart grid, this energy can be used at the point of generation—immediately.”
Although storage capacity is limited, there is a large response on the industry’s side to confront the problem. ABB, a multinational power technology company, has been looking into ways to improve storage technology. Despite being the leading company in the world for power technology, ABB has set up an outpost on Centennial Campus to research and enhance the present grid.
“You need the storage in order to charge up batteries when you can produce the energy, so you can use the stored energy when it’s not sunny, if you’re using solar energy as an example,” Le Tang, the Vice President and Head of the U.S. Corporate Research Center for ABB, said. “We are working on the interface of the renewable sources with the power grid. They don’t naturally go together.”
Narayan’s goal is to be able to apply his new discoveries to the industry, especially for the “smart grid.” He has been working closely with technology companies like ABB, CREE, and Kopin Corporation to develop the connections necessary to make an impact with his new discoveries. Nevertheless, Narayan’s focus is not limited to smart grids. He is first and foremost a materials scientist, so his main concern was to figure out a way to “marry” GaN to silicon. Considering applications for this techniques came later.
Narayan employed the help of former PhD student and now current assistant professor of materials engineering Tom Rawdanowicz to progress the research process back in 2000.
“Narayan is a visionary and when he sees his students working on something, he has a knack to see something much farther down the road more often than the student does,” Rawdanowicz said.
Their research consisted of achieving a “marriage” of GaN on silicon similar to prior existing integrations of GaN on sapphire chips.
“Right now, for GaN, they are using sapphire in two-inch and three-inch wafers,” Narayan said. “If you could increase that to twelve inches, on silicon, that would be like an increase in a factor of 14. More efficient basically.”
Moreover, not only is integrate-GaN on silicon more energy efficient, it is as cheap as dirt, or sand rather.
“Silicon is just sand,” Narayan laughed. “The manufacturing prices are a fraction of that of sapphire.”
However, GaN does not exist in a vacuum.
“It’s interesting working in the field with real world applications, especially with GaN,” Rawdanowicz said.
Besides its use in smart grids, GaN can be used in various sorts of electronics, including LED lighting and high frequency communications for the military.
“The power savings, especially with regards to the environment, can save this country,” Rawdanowicz said. LED lights that use this technology require less energy, last longer, and are brighter, according to Rawdanowicz.
The potential for savings is so great that the government has invested a plethora of resources into the research. Narayan has received much of his funding from the National Science Foundation (NSF), which has been an important contributor to smart grid research. The NSF has poured an additional $18.5 million into the FREEDM Center on Centennial Campus, which is the center for the university’s smart grid research. Moreover, Narayan stressed the importance of this new technology to the nation’s economy.
“This is also an issue of money,” Narayan said. “We get federal grants. This building here was built and maintained by the taxpayers of North Carolina. They need to see the benefits.”
Many businesses have already expressed interest in utilizing GaN to various electronic needs. However, the GaN discoveries have been slow to catch on to the corporate sector, due to its novelty as well as a healthy dose of skepticism on the industry’s part.
“ABB is very involved with the research and development of the smart grid, but the use for Narayan’s new invention, we don’t know yet,” Tang said. “What I understood from him is that this is a new possibility to produce a relatively high performance sensor combination with computing power. However, we didn’t get beyond that level, so we probably need to discuss more how this can be used in the smart grid.”
Before Narayan could even consider marketing integrate-GaN to the power tech industry, he had to pass through the arduous process of acquiring a patent.
“The Internet has completely changed the landscape of the industry,” Narayan said. “As soon as you put out any knowledge, it’s all over the world. You must innovate, protect, and once you have the rights to the technology, you then can contract and make negotiations.”
Nevertheless, GaN and its applications were not easy to sell. Since the completion of the majority of the research in 2005, Narayan fought consistently in the face of rejection for the patent he just earned.
“Some things can be so ahead of themselves that they are perhaps ahead of the people that review them,” Rawdanowicz said. “He wanted to inform the reviewers that it really merited the patent. It had been so long I actually had doubts about the patent. It takes a lot of tenacity. He has that gift and I have to hand it to him.”
In addition to the patent for GaN, Narayan recently won the 2011 Acta Materialia Inc. Gold Medal Award for his research in the field. Despite these exciting new developments regarding GaN and smart grids, there is a lot of work ahead in the future.
“This will not transform overnight,” Tang remarked. “It will be a gradual process that will take 20 more years to integrate this technology into our society.”
However, the future of the smart grid and its components not only depends on experts doing their research but also on getting students integrated into the workforce.
“It’s important that the students have curiosity about this field. We’re trying to build more relations with N.C. State.” Tang makes an important statement, since the average age in the power technology’s workforce is about 50 years. With their office on Centennial Campus, ABB is trying to recruit and initiate student interest.
