Dr. Majid Pahlevani and his team at the Queen’s ePower lab are developing the technologies that will pave the way for a greener, more sustainable future of power generation.
“We don’t want to just harvest solar energy and inject it into the grid, we want to remove the grid and have a self-sufficient system in a house,” he said.
As an assistant professor in the Department of Electrical and Computer Engineering, Pahlevani’s research incorporates the principles of materials and electrical engineering, bridging the gap between two fields. “I saw an opportunity to combine electronics and materials science to create new energy devices that perform better,” he said.
According to Pahlevani, one of the main issues with our current power generation infrastructure is its inefficiency. “You generate power using remote generators that are very far from the cities, and then you use transmission lines to take that power to the end users in the cities,” he said. “You lose a lot of power during transmission, it’s not very reliable, it costs billions of dollars for the infrastructure, and it needs a lot of maintenance.”
A possible solution to these problems is energy that is locally generated, locally stored, and locally consumed. That’s the guiding principle behind one of his main research focuses: micro- and nanogrids. In contrast to typical power grids which could span entire cities, nano- and microgrids are self-sustaining power generation and storage systems that may be as small as a single-family dwelling.
To be sure, there are problems with this kind of distributed system as well, and Pahlevani and his team are hard at work trying to formulate the solutions.
“Let's say you have a rooftop solar panel. You generate electricity and you consume it at your house. The reliability of the system is very important. When it gets cloudy, you don’t want to lose power,” he said. “Nanogrid research is focused on how to create a small-scale grid which can control the power flow between different components in a reliable manner.” To achieve this, Pahlevani and his team are experimenting with using artificial intelligence to control the systems. “You can use AI algorithms to learn about the sun generation profile in your area at different times of the year, the energy load profile, and the energy storage to determine how to manage the power flow in the system,” he said.
Machine learning algorithms feature heavily in Dr. Pahlevani’s current research, including a new smart-LED lighting system that could revolutionize food production, especially in cold climates. First, a sensor within the LED identifies the type of plant, be it a cucumber or tomato, and then uses that information to determine the best lighting regiment to optimize photosynthesis. After that, the system continues to monitor the plants as they grow, adjusting their lighting program in real-time. “Based on the thermal image, and the color of the leaves, it determines how much light the plant needs in terms of intensity and spectrum,” he said.
By tailoring lighting programs to individual plants, the system could drastically improve the efficiency of vertical farms. Pahlevani says the technology, which is currently being tested by researchers at the University of Guelph, could have massive implications for Canada. “The pandemic has made it very clear that being self-sufficient is really important for Canada,” he said. “With this you don’t need any transportation of food, or refrigeration. You can do it organically. It has a lot of advantages.”
A recurring theme in Dr. Pahlevani’s work is the transition from centralized to distributed systems, which he says are “much more powerful and efficient.” To illustrate, he points to the early days of computing when several operators would have to be connected to a single mainframe. “Now we each have a computer in our hands, and this is much more powerful,” he said.
For Dr. Pahlevani, decentralization is more than just an abstract concept. He comes to Queen’s with an impressive breadth of industrial experience, and a proven track record as an inventor and innovator. He currently holds approximately 70 pending or issued patents in the United States.
While completing his PhD at Queen’s, he oversaw a team that, working in conjunction with American and European corporate partners, successfully designed power converters for a small, purely-electric urban vehicle. Afterwards, he spent six years at a company that specialized in rooftop solar microinverters. It was during this time when he realized that solar energy could be an effective countermeasure to the inefficiency of fossil fuels. “These fossils, they store energy from the sun for millions of years, and we are burning that in a matter of days,” he said. “It’s a very inefficient way of doing things, and it’s not environmentally friendly, so getting electricity directly from the sun was a no-brainer to me.”
One of Pahlevani’s most ambitious current projects aims to lessen our dependence on wall outlets to power our appliances. Using printable arrays that are specially tuned to the wavelength of indoor lights, he hopes to see the homes of the future filled with devices that can charge themselves. Before we can get there, however, he says some work needs to be done to boost efficiency. “The efficiency of silicon-based solar cells, commercial ones, is around 20%, and ours are operating at 6-7%, so this is ongoing research,” he said.
The projects listed here are just the tip of the iceberg in terms of Pahlevani’s ongoing research at the ePower lab. He currently has over 25 graduate students and postdoctoral fellows working with him on a variety of projects, including quantum dot LEDs which produce incredibly pure light for different industrial applications, and supercapacitors that could allow the next generation of electric vehicles to be fully charged as quickly as you could fill a tank with gas. Dr. Pahlevani seems encouraged by the enthusiasm and resourcefulness of the younger generation of engineers.
"In recent years, the use of machine learning and AI techniques has expanded beyond information science and signal processing to encompass many more areas of electrical engineering, including power systems, as Prof. Pahlevani's work shows,” said Carlos Saavedra, department head of Electrical and Computer Engineering.
“Younger generations, they are definitely more environmentally conscious and that’s a good thing,” he said. “With climate change, there’s just no future if we continue the way that we are going now, and the first step is to change electricity generation.”