Wondering about the pros and cons of geothermal? We break down geothermal energy and its top advantages and pitfalls as a form of energy storage.
Geothermal energy refers to the heat stored beneath the Earth's surface. Originating from the planet's formation around 4.5 billion years ago and the continuous decay of radioactive isotopes, this massive, untapped energy resource promises vast potential.
Geothermal energy presents a mixed bag of pros and cons. On the one hand, it is a clean, sustainable energy source that can be harnessed for various uses, from heating to power generation. It is also more environmentally friendly than many other energy sources, emitting minimal greenhouse gases.
On the other hand, geothermal energy has location-specific accessibility. Regions with high geothermal activity can easily tap into this energy source, while others have to resort to expensive and potentially environmentally disruptive drilling operations. Additionally, new geothermal processes like Enhanced Geothermal Systems (EGS) can induce seismic activities, posing a potential risk to nearby communities.
Below we break down the pros and the cons to give you a balanced view on this energy source.
The potential benefits of geothermal energy are numerous. First, it produces one-sixth of the amount of carbon dioxide that a natural gas power plant does. According to the Union of Concerned Scientists, a typical geothermal power plant emits about 5% of the carbon dioxide, 1% of the sulfur dioxide, and less than 1% of the nitrous oxide emitted by a coal-fired plant of equal size.
And it's more cost-effective than conventional energy, potentially saving up to 80% off the price of fossil fuel. And unlike solar and wind, which aren't available when the sun's not shining or the wind's now blowing, geothermal is always available - because the Earth is always warm.
Let's deep dive on that last point for a second. Unlike other power sources, geothermal energy is incredibly consistent. This is why it's an excellent base load power source - because it can provide a steady flow of electricity around the clock. Another considerable advantage to this consistency is price stability. Geothermal energy isn't subject to volatile fuel prices, making its cost more predictable and stable over time. While these plants take a considerable upfront investment, the average life of a plant is 30 to 50 years, so the overall return can be high.
Beyond its renewable nature, geothermal energy has various other advantages. Its operations are virtually silent, it uses less land per GWh than most other energy sources, and it provides opportunities for local job creation and economic development. It can be used in a wide range of applications, from heating buildings and sidewalks to generating electricity.
Geothermal energy can be tapped directly from hot springs, steam vents, and other natural sources. Low-temperature geothermal energy, found a few meters below the ground, can be utilized for heating homes, greenhouses, and industrial processes. In areas where high-temperature geothermal energy is easily accessible, such as Iceland, it provides a safe, reliable, and cost-effective source of energy.
Various methods, including dry-steam power plants, flash-steam power plants, and binary cycle power plants, are employed to harness geothermal energy for electricity production. These technologies use heat from the Earth's interior to generate steam, which drives turbines and produces electricity.
Geothermal energy, though incredibly potent and virtually inexhaustible, also has some drawbacks. One of the primary challenges in harnessing this energy is the location-specific nature of geothermal resources. Its production is primarily limited to regions near tectonic plate boundaries, and certain locations may cool down after decades of use. While countries like Iceland have abundant sources of easily accessible hot underground water, others, like the United States, must invest in expensive drilling operations to access geothermal energy.
The high upfront cost of drilling and infrastructure setup, the potential for geological disturbances, and the environmental impacts due to harmful gas emissions and chemical leaks are major hurdles.
Going in order, the upfront costs associated with exploration, drilling, and constructing geothermal plants can be steep, given the wear and tear on equipment in such aggressive environments. This is despite these plants being cheaper in the long run.
Regarding the geological disturbances, the process of EGS involves the injection of high-pressure cold water into drilled spaces to create reservoirs of underground fluid. This process can lead to what's known as "induced seismicity", which is a fancy way of saying "man-made earthquakes." Induced seismicity is one of the biggest concerns of the process of fracking, and its a side-effect of other industrial activities like mining and reservoir impoundment.
The reason these man-made earthquakes can occur in geothermal energy production is due to the hydrothermal stimulation process, where water is injected into hot rocks to generate steam. Any sort of injection into or extraction of fluids from the subsurface can create seismic events, and while many of these man-made earthquakes are too small to be felt, some have been large enough to cause significant damage and loss of life. For instance, a promising EGS project in Basel, Switzerland, was abandoned in 2009 after the injection process caused significant seismic disturbances.
Additionally, geothermal energy production can lead to surface instability and subsidence. As geothermal fluids are removed from the ground, the decrease in pressure can cause the ground above the reservoir to sink. In some cases, this can lead to noticeable changes in the landscape and even damage to structures.
And as for the chemicals, some geothermal fluids contain low-level toxic materials that require careful disposal. Geothermal plants may emit hydrogen sulphide, a gas reminiscent of rotten eggs.
In summary: the dual aspects of geothermal energy—its benefits and drawbacks—are inseparable.
The advantages are remarkable: geothermal energy is a renewable resource, with minimal environmental impact, that can be used for heating, cooling, and power generation. It provides a consistent energy supply, unlike other renewable sources like wind or solar, which depend on weather conditions.
And yet the cons are considerable: the accessibility of geothermal energy is largely dependent on geographical location. Some regions may require extensive drilling operations to access this energy, which can be expensive and potentially environmentally harmful.
The use of technologies like EGS can also trigger minor earthquakes, posing a risk to nearby areas.
Therefore, while geothermal energy has significant potential, it's crucial to be mindful of its downsides to perform an accurate cost-benefit analysis when planning for its utilization.
Despite the challenges, geothermal energy has a promising future. With its numerous benefits and vast untapped potential, geothermal energy is poised to play a pivotal role in the world's energy mix.
Its ability to provide reliable baseload power and its low environmental impact make it an attractive renewable energy source, and countries are exploring it as a viable alternative to add to the energy mix (check out this list of the top 10 geothermal countries from 2022 to see how countries of every region on Earth are exploring its use).
Ongoing research and technological advancements are further improving the accessibility and efficiency of geothermal energy. EGS, for example, could dramatically expand the reach of geothermal energy by allowing for the extraction of heat from rocks deep underground, regardless of location, and so long as their earthquake problem can be resolved. Existing oil and gas infrastructure can be used for EGS as well, which means it can be scaled up at a faster rate.
In the pursuit of a clean, sustainable energy future, geothermal energy stands out as a significant contender. As the world seeks to mitigate climate change and transition away from fossil fuels, the importance of harnessing the Earth's internal heat has never been more critical.
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