McMaster Spotlight: How is McMaster Boosting the Power of Renewables?
Thanks to the development of better power converters and more efficient devices, researchers at McMaster University are making a powerful impact in the fight against climate change.
Dr. Mehdi Narimani, a professor at McMaster University. Original image can be found here.
Dr. Mehdi Narimani believes that more efficient power converters are required in order to meet the growing energy demand in a sustainable way [1]. Power converters are devices that convert the electricity that is outputted by a source, like a solar panel or a wind turbine, into an electrical signal that can be fed directly into the power grid (To learn more about power grids, make sure to check out this article). Power converters are key components of renewable energy systems because the electricity generated by a power source is usually a different kind of signal than the electricity that comes out of your outlets. In order to feed this electricity into the grid, the signal needs to be converted into a different signal with the right properties, such as voltage and frequency [2].
Unfortunately, when the signal is travelling through the power converter and being transformed, it loses some energy due to heat and other losses. The highest quality power converters on the market today have efficiencies of about 90-95%, but more affordable converters are around 75-85% efficient [3]. This means that about 5-25% of the generated electricity is lost just from the power conversion process alone. To put this into perspective, 5-25% of electricity generated by the Sarnia Photovoltaic Power Plant, which is a large solar farm in Ontario, is enough to power 600-3000 homes! In order to recapture this useful electricity, Dr. Narimani is looking into ways to minimize losses in the power conversion process and take renewable energy generation to the next level. His research involves experimenting with new designs for the power converters, as well as using computer simulations to identify which designs will perform the most efficiently. Alongside Rockwell Automation, Dr. Narimani is currently looking at how he can design more reliable power converters that can be used in the heavy industry, which could play a part in renewable energy systems like wind turbines in the future [1].
Mehdi Narimani is not the only researcher at McMaster that is putting their talents towards a sustainable future. Dr. Rafael Kleiman of the Engineering Physics department is also helping to boost the power of renewable energy by creating ultra-high efficiency solar panels. Functionally, solar cells are able to absorb certain wavelengths of light from the sun in order to generate an electric current. However, the efficiency of the cell, or the amount of sunlight the cell is able to convert to electricity, is limited because no single cell is able to capture all wavelengths of light, so the efficiency is usually capped at around 30% [4]. For a more in-depth look at solar cells, check out this article. You can think of the cell as a kind of sunlight-catching net; just like how different objects will be caught in the net if the mesh is woven more tightly, different wavelengths of light can be “caught” by the solar cell depending on a property of the material called the bandgap. Researchers have found that stacking different materials with different band gaps is equivalent to stacking finer and finer nets on top of each other: with every layer, different wavelengths of sunlight can be caught, which allows us to raise that efficiency cap. These stacked-material solar cells are called multijunction solar cells, and they have been found to reach efficiencies of over 45% [5]. Dr. Kleiman and his research team are looking into how to make multijunction solar cells that are not only much more efficient, but also affordable for everyone.
The development of more efficient energy systems, whether it be through the creation of high-performing power converters or by fine-tuning the bandgaps of multijunction solar cells, is an integral part of the global transition to sustainable energy. For more information, you can visit Dr. Mehdi’s research page or Dr. Kleiman’s website and view recent updates on this exciting research.
References
[1] K. Arnott. “Electrical & Computer Engineering professor seeks solutions to energy challenges.” Faculty of Engineering. https://www.eng.mcmaster.ca/news/electrical-computer-engineering-professor-seeks-solutions-energy-challenges (Accessed Jan. 31, 2021)
[2] M. Islam, Y. Guo, J. Zhu, “Power converters for wind turbines: Current and future development,” in Materials and Processes for Energy: Communicating Current Research and Technological Developments, pp. 559–571, Aug. 2013. Accessed: January 31, 2021. [Online]. Available: https://www.researchgate.net/publication/262974138_Power_converters_for_wind_turbines_Current_and_future_development
[3] “Efficiency of Inverters.” Utility Solar Power and Concentration. https://www.e-education.psu.edu/eme812/node/738#:~:text=where%20PAC%20is%20AC,efficient%20%2D%2075%2D85%25 . (Accessed Jan. 31, 2021)
[4] “Professor Rafael Kleiman”. Faculty of Engineering. https://www.eng.mcmaster.ca/people/faculty/rafael-kleiman#overview (Accessed Jan. 31, 2021)
[5] “Multijunction III-V Photovoltaics Research” Office of Energy Efficiency & Renewable Energy. https://www.energy.gov/eere/solar/multijunction-iii-v-photovoltaics-research (Accessed Jan. 31, 2021)