In this blog post, we’ll explore how modern society is currently utilizing the sun’s infinite energy and how we can use it more efficiently in the future.
When we wake up and open the curtains, warm, dazzling sunlight greets us. But as we look out at the suddenly brightened world, we squint and close our eyes again, wishing the sun would disappear—even if just for a moment. In that instant, the sunlight feels like a nuisance. Yet this very sunlight is also a precious gift from nature that supplies us with energy. The rapid increase in energy consumption driven by a growing population is one of the major challenges facing modern society. The solution to this problem lies in solar energy, which is right at our fingertips.
The sun provides an enormous amount of energy—enough to meet the Earth’s entire annual energy needs in just one hour. Solar energy is the technology developed to effectively harness this energy. Solar energy provides us with energy in the form of light and heat.
Examples of the use of the sun’s light energy include solar cells or solar panels used in spacecraft, rooftops, and portable calculators. These devices use “photovoltaic cells.” Photovoltaic cells are made from semiconductor materials, the same type used in computer chips. When sunlight hits a photovoltaic cell, electrons are released from their atoms within the cell, and as these electrons flow through the cell, electricity is generated.
Solar thermal power plants, which harness the sun’s thermal energy, generate electricity by using solar heat to boil water and drive steam turbines, instead of coal or nuclear power. Various technologies are currently being introduced to improve the efficiency of solar thermal power.
One method involves using U-shaped concave mirrors to focus sunlight onto a tube filled with oil, thereby heating the “thermal oil.” The heated thermal oil boils water to drive a steam turbine. To further improve efficiency, some methods use “molten salt” instead of thermal oil. This technology uses movable mirrors to focus sunlight onto a solar collector located at the top of a tower, and the molten salt is heated as it passes through this collector.
Another method involves passive solar energy utilization. This method involves utilizing solar energy in daily life by installing large windows on the side that receives the most sunlight and using flooring and wall materials that absorb solar heat well. These materials store heat during the day and release it at night to keep the building warm. Additionally, installing solar heat absorbers on the roof to heat a boiler can reduce energy consumption.
Solar energy is gaining attention as a pollution-free energy source that produces no pollution or noise. This technology can be applied in various settings. For example, solar cells supply power to buildings and cars, and can generate energy in remote mountainous areas, on satellites, and in places that have not yet had access to electricity.
However, solar energy has the drawback of not functioning at night without storage devices, and it does not work properly even during the day on cloudy days. Furthermore, solar power generation is costly and has the limitation of requiring a large area to absorb sunlight.
Nevertheless, the use of solar energy has increased by about 20% over the past 15 years as efficiency has improved and prices have fallen. Japan, Germany, and the United States are major markets for solar panels, and thanks to tax incentives, solar power systems can recoup their initial investment costs within 10 years. Let’s live by converting this resource, provided free by nature, into energy.
