(From left) Dr Lee Chi-kwan, Professor Tan Siew-chong and Professor Ron Hui Shu-yuen believed renewables are solutions to energy crisis, and smart grid is the key to assure this.
Smart Grid is an electrical grid system related to the control of energy production, conditioning and distribution of electricity. Developed by the three Musketeers from the Department of Electrical and Electronic Engineering (EEE), Professor Ron Hui Shu-yuen, Professor Tan Siew-chong, and Dr Lee Chi-kwan, Smart Grid allows renewable energy to become more applicable by improving the sustainability of the energy supply.
Renewable energy is the common solution to energy crisis and global warming problems. However, to Professor Hui’s research team, renewable energy might be practicable and usable only when smart grid is applied to assure sustainability of power supply. At the first quarter of this year, their research leads to two breakthrough inventions, (i) electric springs and (ii) resonator-embedded insulators with energy-harvesting and wireless-power-transfer functions. These two visionary inventions are expected to play significant roles in real sustainable power supply in the future.
True solution to energy crisis
“The capacity of renewable energy is growing while the supply is unstable. The smart grid should serve to overcome this, or otherwise we can never abandon coal burning and solve the energy crisis,” said Professor Hui, Professor at the Department of Electronic and Electrical Engineering, HKU.
According to a latest United Nations (UN) report, global energy demand is increasing with the world population, and is expected to reach 10 billion in 2050[1]. Energy resources, such as oil, will be running out in 40 to 60 years, whilst coal is also foreseen to be over-consumed in no more than two centuries. Together with the challenges of global warming, renewable energy like solar energy and wind energy is definitely the alternative that will be widely used. Statistics unveiled by International Renewable Energy Agency (IRENA) also shows that the renewables capacity is growing, which leads the share of renewables in total capacity raised by 33% in 2018[2].
Smart grid is an electrical grid system that relates to the control of energy production, conditioning and distribution of the electricity. It has been widely studied in the past decades on various aspects, such as smart meter, smart appliances, so as to explore solutions to energy crisis.
Professor Hui and his research team take the challenge to focus on the research of sustainability of power supply. Although smart meter could be a great tool to monitor the usage of electricity and manage the output efficiency, it’s not necessarily associated with renewables. Professor Hui remarked, “Hong Kong’s usage of renewable energy is less than 1%. Even though the power company launched projects on smart grid or smart meter, it doesn’t mean that we are switching to renewables.” This is also one of the reasons why the team partnered with China Southern Power Grid to design electric-spring devices to stablise the power grid with large penetration of intermittent renewable sources. By using electric springs in a distributed manner over the power grid, the invention will be able to reach a larger area and benefit more people. One of the research partners, Dr Lee said, “making the renewable energy practicable and usable is the true value of smart grid.”
From wireless mobile charging to emergency power backup
Regardless of the fact that using renewables is the growing global trend, there are still challenges dragging down the growth. Statistics from IRENA pinpointed the non-renewable capacity is also expanding, especially in Asia. But why are some regions still using non-renewable energy, and even seeking for other non-renewable alternatives such as nuclear? One of the reasons, as Dr Lee commented, is the stability of supply. “Solar and wind energy are expected to come from different power plants, the supply is easily affected by various factors like weather condition. Therefore, challenges such as how to manage different resources and distribution actually still exist.”
Professor Hui added, “we believe renewables is the solution to energy crisis, and smart grid is the key to assure this. When the growth of renewables reach to a certain level, problems associated with the stability will also be amplified.” Professor Tan said, “among all these considerations, our research is more focused on power stability, quality, and efficiency of the conversion processes of electric energy, and the balance between supply and demand of power within the smart grid system.” He further elaborated with an example, “most of our household appliances only require direct current flow (DC), while the power supply is transmitting alternating current flow (AC) to the buildings. By applying smart grid and advanced power electronic technologies, this kind of conversion can be avoided, which can help to ensure reliable and stable supply of power in a more efficient and cost effective manner. This will be a win-win scenario for both power supply companies and consumers.”
Their second new invention, resonator-embedded insulator with energy-harvesting and wireless-power-transfer functions is also demonstrating how a smart grid can benefit in maintaining renewables supply.
Dr Lee explained, “printed resonators will be embedded in the insulators of high voltage transmission towers, to harvest energy wirelessly from the current flow surrounding the tower, thus ensuring the stability of power supply for the monitoring devices on top of the towers. In serious incidents, such as the 2008 snowstorm in China, the solar-energy powered batteries for the online monitoring sensors of the electric tower ran out of power due to prolonged poor weather, leading to communication breakdown between the transmission towers, power plants and the control centres. It took extra effort for the control centres to figure out the location of the failure in the power network. However, with the resonator-embedded insulator, it will provide continuous and stable power supply for the sensors and thus lead to quicker response and give signals to the control centre continuously and reliably regardless of the weather conditions.”
The insulator with energy-harvesting and wireless- power-transfer functions are planned to be installed in Southern China cities, as part of HKU’s coordinated project with China Southern Power Grid, Tan put this as a future blueprint of smart grid application, “in rural areas or outlying islands, renewables can be even less stable due to the distance of power supply and weather conditions. Also, technical support might be delayed with the transportation arrangement. The micro-grid system assures a self-sufficient power supply in a close area. This is a very encouraging results of our research!”
The team partnered with China Southern Power Grid to design a resonator-embedded insulator for high voltage transmission towers.
[1] “World population projected to reach 9.8 billion in 2050, and 11.2 billion in 2100 – says UN ” https://www.un.org/en/development/desa/population/events/pdf/other/21/21June_FINAL%20PRESS%20RELEASE_WPP17.pdf
[2] Renewable capacity highlights by International Renewable Energy Agency
https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2019/Mar/RE_capacity_highlights_2019.pdf?la=en&hash=BA9D38354390B001DC0CC9BE03EEE559C280013F&hash=BA9D38354390B001DC0CC9BE03EEE559C280013F