Now, the energy derived from movement or “people power” is about to become the next step towards a greener future, thanks to Dr. Ishara Dharmasena and a group of scientists at the University of Surrey and Loughborough University looking to harness the motion around us, such as human motion, wind, waves, vehicles, and machines, and convert it into electricity, allowing the possibility of powering smartphones, sensors, watches, LEDs, and other low-power electronic devices. Dr. Dharmasena is a native of Sri Lanka, having lived in Piliyandala and schooled at Ananda College, Colombo. He had then gone on to complete his undergraduate studies at the Faculty of Engineering of the University of Moratuwa, which was followed by his PhD at the University of Surrey, UK in 2015. The 30-year-old doctor has since completed his PhD in 2019, worked as a Research Scientist at the Sri Lanka Institute of Nanotechnology (SLINTEC), and is currently a visiting senior lecturer at the University of Moratuwa. He is currently working as the Doctoral Prize Fellow at the Wolfson School of Mechanical, Electrical, and Manufacturing Engineering at Loughborough University, UK, where they collaborate with the University of Surrey on this project. TENGs In an interview with The Sunday Morning Business, Dr. Dharmasena stated that the entire team consists of eight people, with him leading the project from Loughborough University’s side. Other supporting members include Prof. Jeremy Coupland and Prof. Stephanos Theodossiades. He stated that Prof. Ravi Silva, another Sri Lankan native, is leading the project along with Dr. Bhaskar Dudem from the University of Surrey. Dr. Dharmasena explained that his interest in renewable energy and smart textiles materialised since when he was doing his BSc, and that interest prompted him to investigate methods of capturing energy in our surroundings in order to turn it into electricity. “I started this project based on one of my blue-sky research ideas at the beginning of my PhD. Therefore, I introduced this area to the University of Surrey; I am among one of the first researchers to work on this technology in the UK.” The technology he is working on – termed Triboelectric Nanogenerators (TENGs) – was first introduced in 2012 by Prof. Zhong Lin Wang at Georgia Tech University in the US. However, with his work, Dr. Dharmasena has managed to present a whole new avenue into the research field, which has led to a better understanding of technology and the development of highly efficient, practical energy-generating devices. “We have all experienced a balloon rubbed on our hair sticking to walls and attracting small pieces of paper, our clothes sticking to our skin on dry days, and the most common of all, lightning. All these happen due to static charging, or the triboelectric effect, where two objects in contact have their surfaces statically charged. TENGs use this triboelectric effect to produce electricity.” He explained that a TENG can be constructed by simply putting two plastic sheets together and coating the opposite sides of the two surfaces in contact with a conductive material like metal. The contact or sliding action of the plastic sheets result in the plastic surfaces being triboelectrically charged, after which these charged triboelectric surfaces are moved relative to each other and electricity is produced via a process known as electrostatic induction. This electric current can be obtained by connecting two wires to the metal layers. “TENGs can be developed using various materials such as plastics (nylon, polyester, polythene, etc.), metals (aluminum, copper), semiconductors (silicon etc.), or a mixture of these materials. They can also be made in different colours, including transparent, and differ when it comes to thickness and shapes,” said Dr. Dharmasena. He stated that these TENGs can be small enough to fit inside a bracelet or a shoe insole, while larger TENGs can be designed to fit on to a pavement or smart floor. In order to capture energy from a person walking, he stated that a TENG of a few square centimetres would be enough, while a much larger device of around a few square metres would be required to harvest energy from ocean waves, vibrations of machines, the movement of vehicles, or wind energy. “These TENGs have the advantage of being extremely lightweight, flexible, stretchable, highly efficient, and durable. Some research groups have shown the capability of TENGs in being developed to mimic some of the functions of human skin (artificial skin or secondary skin), or TENGs that can be implanted into human/animal bodies.” Apart from capturing energy, Dr. Dharmasena stated that TENGs can also act as self-powered sensors (sensors that can power themselves) to detect pressure, speed, environmental conditions, etc., which can be extremely useful in medical applications. He stated they can design and construct smart apparel using fabric-type materials which can be used as a power unit to convert movement into electricity, store it in a battery, or capture and distribute. Alternatively, they can attach TENG modules close to electronic devices, and wear them, such as a smartwatch and health sensor, where TENGs can extract motion energy from walking, running, and arm and leg movements. “Since TENGs can be made using cheap materials and technologies, they can be very cheap. Researchers in the past have calculated the cost of TENGs using optimistic estimations, which amounts to around 2.681 US cents per kWh. However, the actual cost for these devices have still not been evaluated, especially when it comes to large-scale manufacturing,” said Dr. Dharmasena. Progress so far Having been first invented in 2012, Dr. Dharmasena stated that many scientists from around the world have been working on this technology, looking at its different areas of application, such as integrating it to vehicles, pavements, machines, wind turbines, and clothes. These attempts have mainly been to construct prototype devices which can produce high-power outputs and high efficiencies. He went on to state that these prototypes had issues in their technology, stemming from a lack of understanding on how they operate and how they could make the best TENG devices for a given application, which prevented them from being developed into commercial applications. Despite this, in 2017, he went on to develop the first-ever theoretical model to fully explain how these devices work and how they can construct the best and most efficient TENGs. This development later went on to be published in the world’s leading research journals and be widely used by major researchers from around the world. “Our work also resulted in the first-ever direct current-generating TENG, and some of the world’s leading textile-based energy generators, putting us among one of the leading research groups in the world in this scientific field.” He explained that with these developments and the contributions from many other research groups, the area is expanding rapidly and is currently considered as one of the most popular energy-related research areas. This technology is also expected to have commercial applications available in the near future. Dr. Dharmasena stated that the motion energy sources around people – such as human motion, wind, wave energy, machine vibrations, and vehicle movement – can produce significant amounts of mechanical energy and power. Taking human motion as an example, he explained that an average person travelling at walking speed can produce up to 60 W of power. In comparison to this, most of the smart electronic devices that are used today, such as tablets and smartphones, need only a few Watts to operate, while modern health sensors, activity bands, etc. only use a fraction of that energy. “Our recent calculations show that the mechanical energy generated by an elite basketball player during a single game might be roughly enough to power a typical UK household for 10 minutes. Similarly, other energy forms can generate considerable amounts of energy. Therefore, it is critically important to develop green, renewable, sustainable, and efficient technologies to capture this energy and convert it into electricity, such as TENG technology.” Industry interest As the technology stands now, the main focus of TENGs is to convert movement to power relatively low-power small-scale electronic devices. These include mobile electronic devices such as smartphones, tablets, smartwatches, LEDs, small LCD displays, smart clothing, health sensors, devices such as motion sensors, pressure sensors, and pacemakers, Internet of Things (IoT) and 5G technology-related devices, environmental sensors, small-scale wireless communication units, etc. According to Dr. Dharmasena, TENGs can be constructed using conventional textile materials such as polyester, nylon, cotton, wool, etc. in forms of fabrics. Therefore, they can be integrated in almost any type of clothing or footwear. He stated that since TENGs can be constructed using materials like plastics and metals as well, they can also be easily connected to machines, vehicles, etc. to capture available vibrations or movements. “This technology can be engineered to suit different surfaces, so it is not limited to textiles, but can be adapted to floors, tiles, metal surfaces such as machines and vehicles, etc. TENG designs can be particularly effective when they are developed with nanomaterial-based modifications, which give them high power-generation capabilities.” He stated that this has garnered TENGs a great deal of interest from the textile and apparel industry, with global companies such as MAS Holdings and Brandix Group expressing their interest in the initial developments. He went on to state that other research and development-based companies such as DZP Technologies (UK) have also supported their project in the previous years, while more recently, world-leading companies such as Jaguar and Land Rover, Sony, and, leading security companies in the UK have also expressed their support. Sri Lankan talent Speaking in terms of Sri Lanka, Dr. Dharmasena stated that he believes TENG-related products can be readily adapted to the Sri Lankan market as soon as they are available in the international market, which is likely to be within the next four to six years. “TENG technology is a relatively feasible technology to develop even within Sri Lanka, given the correct vision and guidance. Considering we have a very strong textile and clothing industry, and due to the fact that TENGs can be manufactured using conventional textile materials and processes, it would strengthen the existing industry via product diversification and value addition.” He explained that the global wearable electronics market is predicted to reach $ 75 billion by 2025, and the innovations such as TENG technology will provide the country an opportunity to exploit this niche market, thanks to Sri Lanka already having most of the required infrastructure in place. With this in mind, Dr. Dharmasena stated that he is already engaged in research activities at the Department of Textile and Clothing Technology of the University of Moratuwa, alongside Dr. Nandula Wanasekara, and hopes to bring this technology to Sri Lanka. He has already developed some impressive textile-based TENG devices recently. “In my opinion, there are excellent Sri Lankan scientists not only in Sri Lanka, but all around the world. Even within the UK, some of the best-performing scientists are Sri Lankans. In my view, the primary and secondary educations systems as well as engineering and science-related courses through the university system produce extraordinarily talented graduates, with excellent knowledge and research skills. “However, there is ample opportunity in the Sri Lankan system to further develop our research vision, infrastructure, support, funding, and research culture. Over the past few years, I have seen this changing gradually, and an excellent example is countries that have already developed in such a manner, like China and South Korea, especially in engineering and science-related disciplines. I believe the talent is already there; we just need a clear vision, support, and the correct approach to nurture that talent and inspire them in achieving their goals.” The main investment for this project has been through the Engineering and Physical Sciences Research Council (UK), at close to £ 800,000, awarded to the University of Surrey. Apart from this investment, the University of Surrey and Loughborough University have further invested a total of around £ 200,000 through scholarships and fellowships. Dr. Dharmasena stated that they are currently applying for different research grants from various funding agencies and industries to further develop this research area. This unique technology that harnesses “people power” is coming at a time when the need for renewable energy is at its highest. Set to be the greenest energy the world has ever seen, Dr. Dharmasena stated that the first commercial TENG devices are likely to be in the market within the next four to six years. • A future where ‘human energy’ powers industries