Geothermal energy is heat that comes from beneath the ground’s surface. You can encounter this natural resource everywhere on the planet if you dig down deep enough. It was first used as a method of heating buildings in Italy in 1904, and the efforts to expand its use has continued to expand since then.
According to the International Renewable Energy Agency, the growth of geothermal energy has led to 13.3 gigawatts of support in 2018. We can use this heat to power turbines to create electricity, heat buildings naturally, and a variety of other uses. Wells get dug over 5,000 feet deep into underground reservoirs to access hot water and steam to drive turbines that get contented to generators.
Over 20 countries currently use geothermal energy in some way, with the United States leading the way in this renewable resource. The largest field that produces useful fuel is found at The Geysers in California, where 22 power plants have an installed capacity of 1.5 gigawatts over 117 square kilometers.
Several geothermal energy advantages and disadvantages exist that are worth considering while examining this industry’s contributions to our overall needs.
List of the Advantages of Geothermal Energy
1. It produces fewer greenhouse gas emissions than a natural gas plant.
Geothermal energy serves as a renewable, sustainable form of energy that provides an uninterrupted supply of heat. It can be used in homes or office buildings to improve comfort levels or generate electricity. Although the British Geological Survey describes it as a carbon-free fuel, it produces only one-sixth of the CO2 that a natural gas plant produces. That means we can access the power that we need for the modern lifestyle without contributing an excessive amount of greenhouse gases to the atmosphere.
The average geothermal power plant releases about 122 kilograms of carbon dioxide for every megawatt-hour it generates. That’s one-eighth of what a coal-fired power plant generates.
2. Geothermal energy is a 100% renewable resource.
Geothermal energy is one of the most sustainable sources of power that we have on our planet today. Unlike solar or wind energy, there are no interruptions of access that can change how much electricity can be generated to support local communities. It is even superior to hydroelectricity because the threat of drought or changing weather conditions won’t change how we can access this resource.
It sustains its own consumption rate. That means the reservoirs of geothermal energy that we have today have the potential to last for millions of years with routine maintenance and care.
3. The potential for geothermal energy is massive.
Our current use of geothermal energy is below 15 gigawatts for electrical support. Humans consume about 15 terawatts of energy each year. The potential that exists in our planet could be 1,000 times that amount. We could use the reserves that exist below our feet to completely remove our use of fossil fuels that contribute high levels of greenhouse gases to our atmosphere. The only issue that prevents us from using this energy resource is its profitability.
Geothermal energy can be very expensive to develop. We only utilize a small portion of its full potential, with a maximum yield of 2 terawatts the most likely outcome.
4. Geothermal energy provides us with a stable energy resource.
Geothermal energy is one of the most predictable and reliable resources that we have available to us right now. It is possible to predict the power output of a plant using this option with a remarkable level of accuracy. That means this technology and approach can provide us with the baseload energy demands that every community requires.
The power plants using geothermal energy also have a high capacity factor. That means their actual output is very close to the installed capacity. This advantage can limit some scalability when demand levels are high, but backup resources are available. The global average capacity factor is about 75%, but demonstrations as high as 96% have been documented over the past 20 years.
5. Operating costs are affordable when used for personalized heating and cooling needs.
The low energy requirements for a geothermal heating and cooling system is one of the most important reasons to consider this technology for homes and businesses. You will spend a small fraction of what you currently spend on an electrical furnace, a traditional air conditioning unit, or modernized heating oil systems.
There is no exhaust to worry about with your structure because zero combustion is needed to generate the heat necessary to make the indoor environment comfortable. That makes geothermal energy one of the most environmentally-friendly methods to stay cozy indoors that exist right now.
6. Geothermal energy is a highly efficient power source.
The efficiency rate of geothermal energy is one of the highest of any resource available to us today. That includes fossil fuels and renewable options. Natural gas facilities and equipment can operate at efficiently levels approaching 95% in some areas, with innovative technologies coming close to 100%. When we start looking at heating and cooling systems that involve geothermal energy, that rate goes as high as 450% for some installations.
That figure isn’t a typo. Geothermal heat pumps can supply up to 4.5 heating units for every energy unit that it receives. When we look at this advantage in terms of electricity production, then we can create a low-cost method of creating the power we need without significant long-term investments.
7. The maintenance needs for geothermal systems are minimal.
Some geothermal energy systems in the United States have been in service for more than six decades without requiring extensive maintenance. The hardest work that most installations require involve equipment checks and filter changes. All of the other equipment, including the pumps, compressors, and fans, all get housed indoors so that there is no exposure to potential environmental changes.
This advantage also applies to power plants with indoor turbines. That means the environmental impact of continuous servicing goes away, creating even more opportunities to produce energy while saving money simultaneously.
8. Geothermal energy installs on a small footprint.
The typical geothermal energy system for personal use needs a maximum of 600 square feet to provide the heating and cooling needs for a home or business. The trenches for the coils need to be buried at a specific level, but this process can be vertical instead of horizontal. Even when you look at the size of a geothermal plant, you’re looking at a smaller footprint than what a coal-fired or natural gas facility would require.
Although the cost of geothermal energy can be high, the cost savings that become possible can make the system pay for itself over time. A heat pump can save up to 70% on a building’s heating bills and 40% on the cooling requirements. That equates to a savings of up to $3,000 per year for some homes.
9. Four types of geothermal energy power plants can offer electricity support.
Dry steam facilities use steam that comes vented from the ground to drive turbines that generate electricity. Geothermal energy can also work with binary power plants that use steam to heat volatile fluids like butane that vaporize to start the turbine spinning. Flash steam plants will pump hot water into areas of low pressure so that it forms steam that will begin to produce electricity.
Then there is the enhanced system design that creates fractures in hot rock to allow water to flow through the drill site. Then the facility extracts the fluid to produce the energy needed to create electricity.
10. Geothermal power plants can use any form of water to create energy.
Although the preference of a geothermal power plant is to use a freshwater resource to create energy, natural reservoirs may not provide enough fluid to create the needed results. Some facilities have started using wastewater from local processing facilities to heat and inject natural reservoirs to supplement their activities. The boiling effect works to eliminate impurities that could be harmful to others while reducing the overall processing costs. This advantage can even support the environment by creating a lower risk of spillage because of excessive rain or procedural accidents.
11. Anyone can use geothermal energy without needing combustible fuel.
Geothermal energy requires an initial drilling project to access the natural reservoir. Then the facility builds up around that activity to create a plant that provides power to the region. That means there are zero ongoing mining or drilling efforts that must take place to continue operations. Everything occurs locally, which means there are fewer transportation needs to meet when producing electricity. The elements of this advantage mean that fewer emissions occur throughout the entire supply chain since combustible fuels that require replenishment are not part of the overall system.
List of the Disadvantages of Geothermal Energy
1. Geothermal plants can cause earthquakes.
Geothermal power plants are known to trigger small tremors in the same way that fracking activities can create earthquakes. This disadvantage is limited to the area where the drilling and processing activities take place. It isn’t overly destructive, but some of the quakes can be enough to make some people uncomfortable. Scientists measuring The Geysers region in California record about 4,000 shakes over a magnitude of 1.0 each year.
Quakes as large as 4.5 have been recorded with the presence of geothermal energy. When communities sit a couple of miles above the rock fractures that promote hot water and steam use, then earthquakes as minor as a magnitude 2.0 can be felt and shake pictures off of the walls.
2. This resource isn’t available in every region.
Geothermal energy is a location-specific resource that isn’t available in every geographic location. Countries like the Philippines and Iceland can meet over 30% of their electrical demands by using this option, but other nations might not have any access to it. Transporting the heat over long distances creates a significant energy loss that makes it unsuitable for anything but local requirements.
This disadvantage also applies to homeowners who are considering a geothermal heating and cooling system for their home. It works better as a supplemental system to provide indoor air temperature stability. Unless the property is in a somewhat tropical location, it might not be the best option to consider.
3. Geothermal energy has sustainability issues that require consideration.
We have access to groundwater resources thanks to precipitation that seeped through the surface over thousands of years. Some research suggests that there may have been underground reservoirs available throughout the ancient history of the planet. Studies on geothermal energy have found that the reservoirs that supply hot water or steam can get depleted if the fluid gets removed faster than it gets replaced.
Efforts to inject fluid back into the reservoir after utilizing the thermal energy from the heat can sustain this energy resource, but it requires proper management. If injections don’t occur, the resource could disappear. Homeowners don’t face this disadvantage because geothermal energy gets used in a different way.
4. The development of geothermal energy is expensive.
New commercial geothermal power projects are remarkably expensive. The total cost can end up being as high as $7 million for every 1 megawatt of install capacity, which is 2.5 times higher than the cost of a wind turbine that produces the same amount of electricity. That places the installation cost higher than most other forms of energy. Cost savings can happen over time, but there isn’t a guarantee that the initial investment will ever come back to those who put up the money.
Even the installation of a geothermal heating and cooling system is somewhat expensive for businesses and homeowners. A ground source heat pump can be as high as $10,000, and labor can triple that cost. That’s why the payback time can be as much as 20 years, and some systems have a lifespan of only 15 years.
5. Pollution issues with geothermal facilities go beyond carbon dioxide emissions.
An abundance of greenhouse gases can escape from below the ground when tapping into a geothermal energy source. Some of them migrate toward the surface with the power generation activities that occur, with a few eventually making their way to the atmosphere. Although this form of pollution is essential to consider, the problem with this energy resource is that the power plants are associated with silica and sulfur dioxide emissions. The reservoirs can also contain traces of heavy metals like arsenic, boron, and mercury.
That means workers operating in these facilities must take an enhanced approach to safety. Water vaporization can make it easier for the toxic pollutants to make their way into the body, creating potential health hazards over time for some individuals.
6. Odor issues can impact the viability of geothermal energy.
If you have ever walked the paths at Yellowstone National Park, then the smell of sulfur in the air becomes a familiar scent. It’s like you’re smelling wet rotten eggs. The emissions that come from a geothermal energy plant encounter the same issue. Even when you become nose-blind to this issue, the smell on heavy energy production days can drive you back inside. The odor can even seep indoors if a building doesn’t meet the current energy efficiency standards.
Even if you don’t live close to the facility, wind movements can blow the odors your way sometimes. This disadvantage is one of the reasons why you don’t typically see a power plant using geothermal energy in residential areas.
7. Geothermal temperatures require very hot water to operate.
Heated water creates the opportunity to produce geothermal energy, but it can be challenging to create temperatures that are hot enough to create useful outcomes. For a facility to maximize its potential, the underground fluid must reach a minimum temperature of 350°F. That’s significantly higher than boiling temperatures, which means evaporation occurs almost immediately if the water comes into contact with the air.
Lower temperature solutions are useful for home heating and cooling needs, but it won’t create enough energy for electricity generation. Since heating the water so that it reaches the correct temperature is economically viable, the full potential of this resource is not available until new technologies develop in this industry.
The advantages of geothermal energy and power give us the hope to run our current systems in the future without the same adverse impacts on the environment. The sustainability it provides when correctly managed gives it a tremendous advantage that deserves more exploration, despite the significant upfront costs that development would require.
If we can realize the full potential of this energy resource, then the technological investments needed to inspire innovation will offer dividends for multiple generations.
As for now, the overall influence that geothermal power will have on those systems is up for debate. Pricing, subsidies, and new technologies like artificial intelligence create the potential for a lot of uncertainty. That means we must continue to return to these crucial points to see if this energy option is one worth pursuing.
Brandon Miller has a B.A. from the University of Texas at Austin. He is a seasoned writer who has written over one hundred articles, which have been read by over 500,000 people. If you have any comments or concerns about this blog post, then please contact the Green Garage team here.