In this blog post, we’ll break down the process by which electricity is produced at power plants and delivered to our homes into three stages—generation, transmission, and distribution—to make it easier to understand. We’ll also explore the technology and social implications related to the electricity supply.
Electricity Production (Power Generation)
First, let’s look at power generation, the stage where electricity is produced. Power generation is the process of converting various forms of energy—such as mechanical, thermal, and chemical energy—into electrical energy. Power plants perform this function, and typical methods of power generation include thermal, hydroelectric, nuclear, wind, and solar power. Recently, as carbon neutrality and energy transition policies have been promoted worldwide, the share of renewable energy—including wind and solar power—has been steadily increasing. However, depending on each country’s energy policies and the composition of its power generation facilities, thermal and nuclear power are still utilized as important sources of electricity, and the proportion of each power source varies by country, region, and time period.
Social issues related to electricity production are closely intertwined with our daily lives. For example, safety concerns regarding nuclear power plants, local conflicts surrounding the construction of transmission lines and towers, and issues related to the selection of power plant sites are all linked to the electricity production and supply system. The utility poles and transformers we commonly see in our daily lives are also part of this power grid. Thus, electricity is not merely an energy source used through an outlet; it is a core infrastructure that drives society and industry, as well as a critical component subject to various environmental and social debates and policy decisions.
Electricity Transmission
Electricity generated at power plants is not supplied directly to individual households. First, the electricity is transmitted over long distances via substations and transmission grids, and then delivered to homes and factories through regional substations and distribution grids. Since power plants—such as hydroelectric plants in mountainous regions, and nuclear and thermal power plants near coastlines or industrial complexes—are often located far from areas where electricity is consumed, the transmission process, which reliably delivers electricity over long distances, is absolutely essential. The facilities that fulfill this role are transmission lines and transmission towers.
One of the most important technical factors in the transmission process is voltage. To transmit electricity efficiently over long distances, the voltage must be significantly increased. This is because power loss is proportional to the square of the current. When transmitting the same amount of power, increasing the voltage reduces the current, which in turn significantly reduces the resistance losses (I²R losses) generated in the wires. For this reason, ultra-high-voltage (UHV) transmission systems are widely used, and in South Korea, various UHV transmission systems—including 154 kV, 345 kV, and 765 kV—are currently in operation.
As transmission voltages increase, concerns among residents regarding electromagnetic fields and other factors are sometimes raised. To date, international organizations and major research studies have found no conclusive evidence proving a clear health risk to humans when power facilities meet safety standards in typical living environments. However, public interest in the location, environment, and safety of transmission facilities continues, and relevant standards and management systems are being continuously improved.
Electricity Distribution
Electricity delivered to local areas via the transmission grid undergoes a process at the distribution stage to step down the voltage to levels suitable for its intended use before being supplied to homes, factories, commercial buildings, schools, and other locations. At substations and distribution transformers, ultra-high-voltage or high-voltage electricity is stepped down through several stages and ultimately supplied at 220V, the voltage used in homes.
This voltage conversion process allows us to use electricity safely in our daily lives.
There are two main methods of distributing electricity to homes: overhead distribution and underground distribution. Overhead distribution uses utility poles and overhead power lines to supply electricity and is the most common form we see around us. Utility poles installed along roadsides or in residential areas, along with the transformers mounted on them, are typical examples of overhead distribution equipment. Transformers play a crucial role in stepping down the high voltage transmitted from the power grid to a level suitable for use in homes or small businesses.
Underground distribution is a method of supplying electricity by burying power lines underground. In this case as well, transformers operate in the form of above-ground distribution equipment, underground electrical rooms, or underground transformers. Underground power distribution helps improve the aesthetic appeal of urban areas, protects power lines from natural disasters such as strong winds and lightning strikes, and enhances pedestrian safety. On the other hand, it has the drawbacks of higher construction and maintenance costs, and recovery from outages may take longer. For these reasons, overhead and underground power distribution are often operated in conjunction, taking into account local characteristics and economic feasibility.
The distribution boxes and transformer equipment commonly seen along roadsides may appear to be simple metal boxes on the outside, but they contain high-voltage or extra-high-voltage electrical equipment inside. Therefore, members of the public must not open, approach, or tamper with them, and it is important to always follow safety guidelines when near these facilities.
Summary and Conclusion
So far, we have examined the three-stage process by which electricity reaches our homes. First, in the power generation stage, various power plants convert different forms of energy into electrical energy. Next, in the transmission stage, electricity is transmitted at ultra-high voltage to minimize long-distance power losses. Finally, in the distribution stage, the voltage is stepped down to a level suitable for the intended use and safely supplied to homes, factories, and commercial facilities.
While we conveniently use electricity simply by plugging in electrical appliances, behind the scenes, the operation of power plants, the construction of ultra-high-voltage transmission grids, the management of substations and distribution networks, and the maintenance and safety management of numerous power facilities all work together in an integrated system. Furthermore, the power supply system is a core national infrastructure in which various factors—including not only technical issues but also the environment, the economy, energy policy, and cooperation with local communities—interact. Understanding these processes makes it easier to appreciate just how complex the system is that ensures the stable supply of the electricity we use every day.
