Excellent Energy Transformation Processes

The energy sector is advancing rapidly in becoming the sector of our age, and work in this field continues without pause. On one hand, we continue to generate energy through methods and technologies applicable in energy production and use it in various sectors, while on the other hand, as the value of energy is better understood, public offerings and share values in investment sectors for such systems are steadily increasing. Have you ever thought about why the energy sector is so popular right now, or where you think this process will go? Because from long-standing experience we know that a developed product, method, or technology—whatever we call it—eventually faces depletion after some time, or a different side effect emerges, and after a painful process, new searches begin and we move on to something else. We can say that this process is an ongoing adventure of producing and consuming. Actually, underlying the current popularity of the energy sector are searches for a return to natural energy sources, while on the other hand there is the damage done to nature and increasingly rising costs resulting from the use of petroleum derivatives. For precisely these reasons, the search for new applications in energy technologies continues relentlessly. The fact that energy obtained from natural energy sources does not face the kind of difficulty in obtaining it that petroleum derivatives do, provided there is no problem with the natural energy source itself, is certainly a factor. For example, energy obtained from natural sources such as the sun or wind carries quite low risk in terms of these sources. Beyond this, when we consider the damage petroleum derivatives have done to nature, the concept we call carbon footprint comes into play, and the damage to the environment is very significant. For precisely these reasons, we have turned toward natural sources. The process actually began in a sense with electric vehicles emerging as an alternative to vehicles that use petroleum and diesel as fuel. In the early stages, when the brake was applied, the pressure generated from the pushing force was stored as electrical energy and used in the advancement phase. Actually, for low speeds this technology is quite a good one. If you imagine being in heavy traffic, it consists of constant movement; stop and go, stop and go. Based on the force applied by the driver pressing the brake during stops, we can base the use of energy generated from that force. This reminds us of gym stationary bikes that light up when you pedal them. Of course this technology can be readily used at low speeds, that is, in road conditions that frequently require stopping. You will recall that in the first electric vehicles to come out, use with electricity was possible only up to a certain km/h speed. However, nowadays vehicles can reach whatever maximum speed they normally can and can be used for longer periods. This is a very large transformation and a process requiring and containing very large technological searches and innovations. The only reason behind energy being usable from 50 km/h speeds to, for example, 180 km/h speeds has to do with chemistry. Because there is serious energy conversion, a serious energy storage system in the background. Among the systems used, especially lithium-based and nickel-based batteries are heavily preferred. These batteries have certain differences in their usage. For example, lithium batteries are lighter and have higher capacity, while nickel-based batteries charge faster and display balanced performance. For this reason, the places where they are preferred can vary. Well, today, from waste, which has become one of the biggest problems, especially plastic waste, cannot we obtain energy? If we solved this problem through scientific means, and offered an efficient alternative to the current energy sector, do you think this would be possible? Of course, why not, although serious work would need to be done on it, it is not an impossible situation. For example, there are luminescent bacteria, energy storage systems we produce and store every day in the human body. While plants produce nutrients for themselves using sunlight and obtain energy from these nutrients, why should we not convert these types of energy into electrical energy? Come on, let us see what types of energy systems are used in our bodies and what forms we can use them in. In the human body, substances stored as energy reserves are fundamentally fats, carbohydrates, and proteins, the metabolite type turned to last. Their most important common characteristic is that they are composed of carbon compounds. The variation in their preference depending on usage areas in the body accounts for their diversity. However, another common point is this chemical: Acetyl CoA. Acetyl CoA is oxidized for energy production and is the first component of the krebs cycle, the cycle that enables energy production. At the same time, by carrying carbon atoms into this cycle, it enables the energy released from their breakdown to be used by metabolism. Now let us look at the type of energy released here. The chemicals you see inside the reaction circle shown beside are NADH and FADH2, chemicals that exit the cycle for energy production. As a result of these chemicals being converted through enzymes, ATP energy is obtained. Approximately 7-12 kilocalories of energy are produced from the breakdown of 1 mol of ATP. This produced energy is consumed in daily activities. For example, cycling for half an hour means approximately 300-400 calories. If we also take into account that you produced electrical energy by pedaling for half an hour on this bicycle, then electrical energy can be produced using biological bodies with the help of molecules that are energy reserves. Where can we use this type of energy? That is, if we think about where metabolic energy type can be used in daily life, remember we mentioned waste earlier. When we categorize those waste streams, each contains serious carbon bonds. If by breaking the bonds between these carbons we can reach Acetyl CoA, the first molecule of the cycle given in the figure above. Now as a result of the cycle in which Acetyl CoA will participate, we will have reached ATP energy, what we call biological energy reserves. Using the bond energies in the structure of this biological energy reserve ATP, when the energy produced calorically is converted into electrical energy, we may have achieved energy production that will light our homes and power our cars. If we think of obtaining all these processes through a cycle via bacteria, it could be a perfect energy engineering plan in terms of energy production. We can think of it this way; while there are even fungi in nature that break down plastics and produce nutrients for themselves from them, actually the foundation of energy, its production and storage processes—the greatest architects are natural resources and the chemical diversity in natural organisms. References • Doğan, U., Erfidan, T., & Bilgin, M. Z. (2016). Energy Storage of Useful Braking Energy in Electric Vehicles. Journal of Advanced Technology Sciences, 5(2). • Winjobi, O., Kelly, J. C., & Dai, Q. (2022). Life-cycle analysis, by global region, of automotive lithium-ion nickel manganese cobalt batteries of varying nickel content. Sustainable Materials and Technologies, 32, e00415. • Alabduladhem, T. O., & Bordoni, B. (2022). Physiology, krebs cycle. In StatPearls [Internet]. StatPearls Publishing. Dr. Ceren Türkcan Faculty Member Biomedical Engineering Faculty of Engineering and Architecture İstanbul Arel University