In this blog post, we will take a closer look at the potential of geothermal energy and how it can be used amid the energy crisis and environmental issues.
Humanity is coming to the point where it must prepare to say goodbye to fossil fuels, which have been with us for more than 100 years. The global population exceeded 8 billion on March 1, 2024, and the rate of population growth is expected to continue to accelerate for some time. As a result, global energy demand is increasing exponentially, and the existing fossil fuel-based energy system is showing its limits in meeting this demand. Moreover, as concerns about climate change and environmental pollution grow, there is an urgent need to reduce dependence on fossil fuels and find more sustainable energy sources.
Energy is essential for the survival of humanity, and for the past 100 years, most of the energy has been obtained from fossil fuels such as oil, coal, and natural gas. However, these fossil fuels are non-renewable resources, and studies have shown that their reserves are gradually decreasing, and that they will only be available for use for the next 30 to 100 years. This can be a great crisis and an opportunity for humanity at the same time. This is because humanity can create a better future by developing new energy sources and innovating the way we use existing energy.
In this situation, renewable energy has begun to rise, and various forms of energy sources are being developed and research is being actively conducted to increase their efficiency. While energy sources such as solar, wind, and hydroelectric power are already widely used, geothermal energy, which is relatively less well known, is attracting attention. Geothermal energy is an energy source that uses the heat from the interior of the earth and offers unique advantages that are different from other renewable energy sources. Although not much research has been done on geothermal energy, this technology is essential to prepare for an era of energy shortages.
In the broader sense of geothermal energy, hot springs, which have been used by humans since ancient times, can also be included in this category. Hot springs are the simplest form of geothermal energy that uses naturally occurring geothermal heat. However, strictly speaking, the construction of a geothermal power plant in the town of Larderello in Tuscany, Italy in 1904 can be said to be the beginning of geothermal energy in the modern sense. In 1911, commercial geothermal power generation began here, and since then, geothermal power generation has grown steadily with the construction of many geothermal power plants in New Zealand and other countries. As a result, the total global geothermal power generation capacity will increase to approximately 16,355 MW by 2023.
As of 2023, the geothermal power generation capacity is largest in the United States (approximately 3,900 MW), Indonesia (approximately 2,418 MW), the Philippines (approximately 1,952 MW), Turkey (approximately 1,691 MW), and New Zealand (approximately 1,042 MW). However, what we should pay more attention to than simply the large power generation capacity is the share of geothermal energy in the total power generation capacity of each country. For example, the United States has the largest geothermal power generation capacity in the world, but its share of geothermal power generation is relatively low because it also has the largest total power generation capacity in the world. On the other hand, geothermal power generation accounts for about 30%, 27%, and 25% of the total power generation in Iceland, the Philippines, and El Salvador, respectively. Geothermal power generation, which accounts for such a high proportion, makes a significant contribution to national energy independence.
Before learning about the advantages of geothermal energy, it is necessary to first understand the principles of geothermal energy. There are many technologies that utilize geothermal energy, but they can be broadly divided into direct use and indirect use technologies. If the temperature of the geothermal water is above 150°C and it is easy to produce steam, indirect use technology is used. This is done in the same way as binary power generation, where two pipes are installed by digging deep into the ground, and water is poured into one pipe, causing the water heated by geothermal energy to turn into steam and rise to the other pipe, which in turn rotates the turbine to generate electricity. On the other hand, if the temperature of the geothermal water is below 149°C, direct use technology is used to draw the geothermal water directly. This is used for district heating, greenhouse heating, etc. and can also generate binary power. Both technologies can be described as environmentally friendly technologies with almost no risk of environmental pollution.
Geothermal energy has many other advantages. First, geothermal energy is similar to other renewable energy sources in that it is renewable, but what makes it different is that its energy source is located deep within the earth. Because geothermal energy uses heat deep within the earth, it is not affected by the weather, making it easy to predict and enabling stable power generation 24 hours a day. As a result, it has an excellent actual operating rate and is considered a reliable energy source. In addition, geothermal energy is environmentally friendly because it does not produce any waste, and it is free from various ethical and health issues. Moreover, because it does not require raw materials, maintenance costs are relatively low.
However, geothermal energy also has two fatal drawbacks. First, the initial cost is very high. Building a geothermal power plant requires a lot of equipment costs, but the cost of drilling the ground to install pipes several thousand meters deep is particularly significant. Second, the number of areas where it can be installed is limited. Geothermal energy occurs everywhere on the surface, but it can only be generated with high efficiency in areas with high rates of temperature rise. As a result, geothermal power generation is mainly carried out in areas located at the boundary of the plate, which is why Iceland, the Philippines, El Salvador, and Indonesia have high geothermal power generation efficiency. Recently, with the development of indirect utilization technology, geothermal power generation has been attempted in areas relatively far from the boundary of the plate, such as Germany and Australia, but the technology is still insufficient.
We learned about the history, power generation capacity, principles, and pros and cons of geothermal energy. South Korea is considered to have a low potential for geothermal power generation because it is relatively far from the plate boundary, but investment in technology development is essential. South Korea, which does not have many energy resources, needs to invest in renewable and stable energy sources such as geothermal energy for long-term energy security and economic development. To maximize the potential of geothermal power generation, we must actively explore effective areas and develop technologies that can increase power generation efficiency. This will be an important factor in determining the future competitiveness of the country.
