In this blog post, we will explore how energy storage technology is advancing for a sustainable future, examining its importance and potential applications.
Energy signifies the capacity to do work and is utilized in various forms in our daily lives. Examples include electrical energy to power smartphones, chemical energy to move vehicles, and thermal energy to generate electricity. Energy is an essential element in human life and an indispensable resource in modern society. The energy we use not only makes our lives more convenient but also directly impacts the economy, industry, and the environment. Therefore, using energy efficiently has a significant impact not only on individual lives but also on the future of nations and the entire planet.
However, since resources for energy production are finite, we must conserve and use energy efficiently. Energy conservation should be approached not merely as a cost-saving measure, but as a means to protect resources and preserve the environment. Furthermore, due to the nature of energy generation facilities, once operational, they supply a fixed amount of energy until the end of their lifespan, potentially creating imbalances between supply and demand. For instance, energy shortages occur during daytime peak usage hours, while surplus energy accumulates at night. To resolve this, energy storage technology is essential—functioning much like banking, where excess energy is stored during surpluses and borrowed during shortages. Such technology plays a crucial role in designing a more sustainable future.
Energy storage methods can be categorized by principle into mechanical storage, electrical storage, thermal storage, biological storage, and chemical storage. Each storage method can be compared based on energy conversion efficiency and energy density. Energy conversion efficiency indicates how much of the stored energy can actually be utilized, while energy density represents the amount of energy produced per unit weight or volume. These two factors are crucial criteria for evaluating the efficiency of energy storage methods. For example, a storage method with high energy conversion efficiency can minimize energy loss, while high energy density allows more energy to be stored in less space.
Mechanical storage methods convert surplus energy into mechanical energy for storage. Pumped storage dams and compressed air storage are prime examples. Pumped storage dams store energy during periods of low energy consumption by releasing excess water from hydroelectric dams. They pump this released water back up to a higher elevation and store it, using it for power generation during periods of high demand. While this method has low energy density, it is a practical way to store large amounts of energy and is already widely used. Compressed air storage involves compressing gas to reduce its volume for storage. When needed, the stored gas is released through a narrow passage, using the pressure to drive turbines for power generation. Simply put, it’s like inflating a balloon to store energy when it’s abundant and then using the compressed air when needed. This method primarily involves creating underground cavities to store air, requiring technology to maintain airtight integrity. A drawback is that the cavity creation process emits significant pollutants.
Thermal storage involves using surplus energy to heat an object and then reusing the stored thermal energy when needed. For example, installing thermal storage walls for winter heating allows the storage medium to absorb surplus solar thermal energy during daylight hours. After sunset, when temperatures drop, heat is released from the storage medium to provide heating. Similarly, using water tank walls allows water, which has high specific heat capacity, to store solar thermal energy during the day and use it for heating at night. A disadvantage of thermal storage is the difficulty in converting stored heat into other forms of energy. That is, energy stored via thermal storage cannot be converted into electrical energy for use; it can only be utilized in its thermal form. However, thermal storage significantly improves the heating and cooling efficiency of buildings, playing a crucial role in sustainable architectural design.
Electrical storage methods involve charging surplus electrical energy into batteries such as lead-acid or lithium batteries for later use when needed. This method is most commonly used for small-scale power supply rather than large-scale power supply. A prime example is the battery in portable electronic devices. The drawbacks of this method include easy discharge and the difficulty of storing large amounts of electricity. Nevertheless, electrical storage methods are gradually increasing in efficiency through continuous technological development and innovation. They are also expected to enable more applications through integration with renewable energy sources. The largest operational electrical storage system currently in use is located in Fairbanks, Alaska, USA. This system can supply 26 MW of electricity for 15 minutes and 40 MW for 7 minutes, providing backup during emergencies like power outages.
Biological storage is an energy storage method utilizing plants, essentially involving growing them. Plants store solar energy through photosynthesis, and this stored energy can be used when needed. The method of drying and burning cultivated plants to obtain energy is called biomass, while using sugars stored in plant bodies as fossil fuel substitutes through chemical processes is called biofuel. While these biological storage methods receive significant attention for their environmental friendliness, they have the drawback of being difficult to artificially regulate energy quantities in the short term. Furthermore, the resources, time, and environmental impacts required in the production processes of biomass and biofuels must be considered. To ensure true sustainability, more research and improvements are necessary.
The most well-known chemical storage method is hydrogen. This involves generating and storing hydrogen during periods of excess energy through methods like water electrolysis or thermal decomposition, then using it later. The hydrogen produced here is widely used as an energy source for fuel cells. However, compared to natural gas (methane), which is currently widely used, hydrogen has a lower energy density, meaning larger quantities are required. Furthermore, hydrogen’s low energy density necessitates significant technological development for its storage and transportation. Nevertheless, hydrogen holds great potential as an eco-friendly energy source to play a crucial role in future energy systems, and related research and investment continue.
We have now examined various energy storage methods. Humanity must use energy to survive, and since the energy we obtain comes from limited resources, it must be used wisely. However, producing large-scale energy on demand is difficult to achieve instantly. Therefore, energy storage technology is absolutely necessary, enabling us to balance energy demand and supply. Furthermore, various energy storage technologies are being developed and researched, and as these technologies advance, we will be able to build a more sustainable energy system. Research and investment in energy storage technology must continue in the future, as this will be a crucial task for our future.
