In the face of exponentially growing energy demand and the threat of fossil fuel depletion, humanity is preparing for a transition to renewable energy sources, including geothermal energy, to address climate change and environmental pollution.
The time is coming when humanity must prepare to say goodbye to the fossil fuels that have served us for more than a century. The global population surpassed 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 growing exponentially, and the existing fossil fuel-based energy system is showing its limitations in meeting this demand sustainably. Furthermore, growing concerns about climate change and environmental pollution have made it urgent to reduce our reliance on fossil fuels and find more sustainable energy sources.
Energy is essential for human survival, and for the past 100 years, most of our energy has been derived from fossil fuels such as oil, coal, and natural gas. However, these fossil fuels are non-renewable resources and their reserves are dwindling, with studies suggesting that they will only be available for the next 30 to 100 years. This is both a crisis and an opportunity for humanity. By developing new sources of energy and revolutionizing the way we use energy, we can create a better future for humanity.
This is where renewable energy comes into play, and researchers are actively working to develop different forms of energy sources and increase their efficiency. While solar, wind, and hydroelectric energy are already widely used, geothermal energy is a relatively unknown source that is gaining traction. Geothermal energy is an energy source that harnesses heat from the earth’s interior and offers unique advantages over other renewable energy sources. Although geothermal energy hasn’t been studied much, it’s essential to prepare for an era of energy scarcity.
If we look at the history of geothermal energy more broadly, we can include hot springs, which have been used by humans since time immemorial. Hot springs are the simplest form of geothermal energy use, harnessing naturally occurring geothermal heat. However, technically speaking, the beginning of geothermal energy in the modern sense was in 1904, when a geothermal power plant was built in the town of Larderello in the Tuscan region of Italy. Commercial geothermal power generation began there in 1911, and since then, geothermal power has grown steadily, with many new plants built in New Zealand and elsewhere. As a result, the total global geothermal power capacity is expected to reach about 16,355 MW in 2023.
As of 2023, the United States (about 3,900 MW), Indonesia (about 2,418 MW), the Philippines (about 1,952 MW), Turkiye (about 1,691 MW), and New Zealand (about 1,042 MW) have the largest geothermal power capacity. But what’s more important to note than just the amount of capacity is the share of geothermal energy in each country’s total electricity generation capacity. For example, the United States is the world’s leader in geothermal power capacity, but it is also the world’s leader in total electricity generation capacity, so geothermal power accounts for a relatively small share. Iceland, the Philippines, and El Salvador, on the other hand, account for about 30%, 27%, and 25% of their electricity generation, respectively. This is a significant contribution to a country’s energy independence.
To understand the benefits of geothermal energy, it’s important to understand how it works. There are many different technologies that utilize geothermal energy, but they can be divided into two main categories: direct and indirect. When the temperature of the geothermal water is above 150°C, which makes it easy to produce water vapor, indirect utilization is used. This is the same as binary power generation, in which two pipes are dug deep into the ground, and water flows through one pipe, causing the geothermally heated water to turn into water vapor and rise up the other pipe, turning a turbine to generate electricity. On the other hand, if the temperature of the geothermal water is below 149°C, direct utilization technology is used to draw the geothermal water directly. This can be used for district heating, greenhouse heating, and even binary power generation. Both technologies are environmentally friendly, with little risk of pollution.
Geothermal energy has many other advantages. First, geothermal energy is similar to other renewable energies in that it’s renewable, but the difference is that its source is inside the earth. Because geothermal energy harnesses heat from the earth’s interior, it’s not affected by the weather, making it highly predictable and reliable around the clock. This makes it a reliable source of energy with a high actual utilization rate. Geothermal energy is also environmentally friendly, as it doesn’t produce any waste and is free from various ethical and health concerns. Plus, it doesn’t require any raw materials, so maintenance costs are relatively low.
However, geothermal energy also has two fatal flaws. The first is that it has a very high initial cost. Building a geothermal power plant is expensive, especially the cost of drilling into the ground to install pipes thousands of meters deep. Second, there are only a limited number of areas where it can be installed. Geothermal heat can be found anywhere in the earth’s surface, but it can only be harnessed at high efficiency in areas with high rates of ground temperature rise. This is why geothermal power is mostly developed in areas on the boundaries of tectonic plates, which explains why Iceland, the Philippines, El Salvador, and Indonesia are among the most efficient geothermal power producers. In recent years, advances in indirect utilization technology have allowed geothermal power to be developed in areas relatively far from the plate boundaries, such as Germany and Australia, but the technology is still not mature.
We looked at the history, capacity, principles, advantages, and disadvantages of geothermal energy. South Korea’s geothermal power potential is considered low due to its relative distance from plate boundaries, but investment in technology development is nonetheless essential. As a country with limited energy resources, investing in renewable and reliable energy sources like geothermal energy is essential for long-term energy security and economic development. To maximize the potential of geothermal power, the country needs to explore effective sites and actively develop technologies to increase power generation efficiency. This will be an important factor in determining the country’s competitiveness in the future.
