This article explores how lightning strikes occur and the potential to harness their electrical energy, and whether developing new materials that can store it could help solve future power shortages.
“Whoosh!!!” As a child, we all have memories of hiding under the covers in fear, or getting excited when lightning and thunder struck. But have you ever wondered about the flash of lightning and the rumble of thunder? More importantly, have you ever thought about the electrical energy generated by lightning? If we had the technology to store electrical energy with instantaneous voltages of hundreds of millions of volts and currents of 20,000 amps, could we solve the recent power shortages?
Materials that can store this kind of energy are what we call new materials. The dictionary definition of a new material is a material that can be combined with raw materials to create new performance and uses that have never existed before. We’re going to talk about materials engineering, which is the process of developing new materials that can capture the energy of lightning, as well as materials for many other applications.
Technologies that can store electricity have long been the subject of research, starting with the Leyden jar in 1745. In the early days of research, a glass jar was filled with water and corked, and a wire or nail was driven through the cork to touch the water in the jar. To charge the jar, the exposed end of the wire was touched to a device that generated friction electricity. When the wire was held in the hand after the contact was broken, an electric shock was felt, proving that electricity was stored. These devices were further refined and eventually led to the modern capacitor.
The capacitor, which evolved from Leyden’s bottle, is a device that collects charge in an electrical circuit. You may be wondering what this has to do with materials. Lightning generates enormous voltages and currents for a short period of time. To store this electrical energy, we need a capacitor that can store a lot of energy for a short period of time. Developing the materials used in these capacitors is what materials science is all about.
However, the concept of storing energy may not make sense if you don’t know how lightning comes to have so much energy. So let’s talk about how lightning is created and the electrical energy it contains. The process of a lightning strike can be divided into two main steps. The first is the electrification of water and ice in the clouds, and the second is the electrostatic attraction between the clouds and the ground.
In storm clouds, wind causes water droplets and small ice crystals to rub against each other. This friction causes the particles in the cloud to become electrically charged. The ice takes electrons away from the water, giving it a (+) charge, and the water droplets, which have relatively more electrons, have a (-) charge.
Before it starts to rain, the heavier water droplets in the clouds collect at the bottom of the cloud, making the bottom of the cloud negatively charged because it has more electrons, and the top of the cloud positively charged because it has less electrons. When enough negative charge collects at the bottom of the cloud, lightning appears as a bright ball of light at the bottom of the cloud. This is actually a collection of negatively charged electrons in the clouds. Now, when these electrons fall to the ground, lightning strikes. But why do the electrons in the clouds fall to the ground?
The ground is charged, too, and the biggest factor that can affect the formation of charges on the ground is the placement of charges in the clouds. The strong negative charges that form at the bottom of the clouds exert a pull on the electrons on the ground, pushing them away, leaving the ground relatively positively charged.
This creates an electrical attraction between the positively charged atoms on the ground and the negative charges at the bottom of the cloud, causing the electrons to fall from the cloud to the ground, and electricity begins to flow. The streaking across the sky, which we call the flash of lightning, is the path the electrons take as they collide with atoms in the air. As they do so, the atoms in the air that collide with the lightning emit heat and light, making the lightning even brighter. In other words, the light of lightning is the light from electrons colliding with air on their way down to the ground.
In other words, lightning is the process of countless droplets of water in a cloud becoming electrified and falling to the ground. The voltage and current generated at that moment can be hundreds of millions of volts and 20,000 amps. What is needed to store this electrical energy is a new material. The materials for the metal plates used in storage batteries are one example of what the Department of Materials Science and Engineering is researching.
Based on the research to date, research using batteries is particularly active in Japan. However, lightning strikes occur infrequently and are not uniformly located, which poses a major challenge to research. For this reason, it may not seem like there is much merit in this research from an economic perspective. However, if we take advantage of the rain and lightning that often occurs in the summer, lightning could help solve the severe power shortages that we experience not only in the summer, but in all seasons.
To recap, lightning generates a tremendous amount of energy when it is created. Lightning comes with a voltage of 100 million volts, and if we can store this energy, we can solve our energy problems. In materials science, we are developing materials that have many real-life applications, such as fibers, semiconductors, and new materials. It is still difficult to develop a technology to store explosive energy instantaneously, but with more time and research, it is expected that we will be able to develop materials that can store the energy of lightning.
