[Science World] The Best Way to Create a Clean World: Energy Harvesting

How does humanity obtain energy? In the early days, people simply ignited natural resources such as wood or animal fat to produce light and heat. Then, they learned how to create steam engines that boiled water using fossil fuels to generate power, which became the catalyst for the Industrial Revolution. With the discovery of how to generate electricity, human civilization rapidly advanced. The problem is that we still obtain energy from underground resources, and this method is a cause of global warming. So, is there no way to solve this problem? While it is difficult to call it a perfect solution, there is an optimal approach. Instead of "mining" energy, we should "harvest" it. This concept is called "Energy Harvesting."

Energy does not disappear; it only changes its form. Solar energy becomes wind, and the energy from coal transforms to power trains. In other words, if we can harvest energy that was previously considered unusable and discarded, we can greatly reduce our energy concerns.

The earliest form of energy harvesting by humanity was probably windmills or water wheels. They harvested the power of wind or water to perform tasks such as threshing. On the other hand, the latest energy harvesting technologies mainly focus on producing "electricity." By attaching thermoelectric devices that convert temperature differences into electricity where hot heat is generated, electricity can be continuously obtained from those places. Using the same principle, photovoltaic cells can generate electricity from sunlight. The "turbine" method, which generates electricity by turning propellers with the flow of fluids (water or wind), is also frequently used. This method is widely applied in tidal, wave, and wind power generation. The "piezoelectric device" technology is also commonly used; it is a special material that converts pressure into electricity.

There are three main types of energy that can be obtained through energy harvesting. The first is natural energy, commonly called "renewable energy." This includes wind power, solar power, solar heat, tidal power, wave power, geothermal, and hydropower.

The second is energy wasted at large production facilities such as factories or power plants. An example is supplying warm water (waste heat water) discarded from power plants for local heating, agriculture, or aquaculture. Factories and power plants generate a lot of waste heat, and thermoelectric devices installed in such places can generate additional electricity. For instance, the Korea Ceramic Technology Institute is jointly constructing a hydrogen power plant facility with SK Eco Plant in the Busan Eco Delta Smart City national pilot city (scheduled for completion in 2025), where an industrial waste heat recovery demonstration system using new thermoelectric materials is being established. Even Internet Data Centers (IDCs) are increasingly required to install such systems, making waste heat recycling systems in current industrial systems no longer optional but essential.

Lastly, energy wasted in daily life can also be harvested. For example, one can consider creating "power-generating roads" by widely installing piezoelectric devices on roads that produce electricity simply when cars pass by. Other ideas include toilets that generate electricity when flushed or devices that convert body heat into electricity to charge smartphones. Depending on creativity, there are countless ways to harvest wasted energy.

Energy has a thousand faces because its form can be freely changed. Depending on the choices we make, its face can take any shape. Creating an energy system that benefits humanity and preserves the environment depends on our efforts.

Jeon Seung-min, Science and Technology Writer