A renewable energy source is geothermal energy. It entails capturing the heat that is contained within the Earth’s surface, or beneath our feet. It can be used to produce energy on a big scale (utility level), as well as to heat and cool homes and businesses on a smaller scale.
Despite being used for a long time, geothermal energy is less well-known than other alternative energy sources like solar and wind power.
We’ve put together a quick summary of this power source’s main advantages and disadvantages to assist you in learning more about it; you can also find more in-depth information further down the page.
The pros and cons of geothermal energy
| Pros | Cons |
|---|---|
| Generally environmentally friendly; does not cause significant pollution | Some minor environmental issues |
| Renewable and sustainable | Sustainability relies on reservoirs being properly managed |
| Massive potential | Location-specific |
| Reliable | High initial costs |
| Great for heating and cooling | Can cause earthquakes in extreme cases |
What is geothermal energy?
Rocks and water make up the Earth’s crust, and beneath that lies a layer of hot, molten rock (magma). Magma is extremely hot—even hotter than the sun’s surface.
Magna’s heat is a significant source of energy that can be used to create electricity. We drill into the earth to accomplish this, and generally speaking, the lower you go, the hotter it gets.
Steam is produced when water is heated using the underground heat. After that, a turbine elevated above the ground is spun in order to generate electricity for the grid.
A constant and reliable renewable energy source, geothermal is virtually entirely pollution-free.
Advantages of geothermal energy
1. Environmentally friendly
Most people agree that geothermal energy is environmentally benign.
A geothermal power plant has a negligible carbon footprint. According to the EIA, an average geothermal power plant emits 99% less carbon dioxide (CO2) for each megawatt-hour (MWh) of electricity it produces.
Utilizing geothermal energy has certain polluting effects, however they are minimal in comparison to the pollution caused by traditional fossil fuels like coal and natural gas.
It is thought that furthering the development of our geothermal resources will aid in the fight against global warming.
2. Renewable and sustainable
Geothermal reservoirs are refilled organically and derived from natural resources. Consequently, geothermal energy is a renewable energy source.
Another term for renewable energy sources is “sustainable.” In contrast to conventional energy sources like coal and fossil fuels, geothermal energy is a resource that can support its own consumption rate.
Our geothermal reserves contain energy that, according to scientists, will actually last for billions of years.
3. Massive potential
Currently, 17 terawatts (TW) of power are consumed globally each year from both fossil and renewable energy sources.
Although that may seem like a lot, the Earth actually contains many times more energy than that! But the majority of geothermal energy is either expensive or impossible to acquire. Between 0.035 and 2 TW are realistic estimates for the potential of geothermal power facilities.
Only 12.7 gigawatts (GW) of energy are now produced by geothermal power plants worldwide, however installed geothermal heating capacity is slightly higher at 28 GW. This indicates that there is a large window of opportunity for more geothermal energy production.
4. Stable
A dependable source of energy is geothermal energy.
With surprising accuracy, we can forecast a geothermal power plant’s electricity production. With solar and wind, on the other hand, the weather has little effect on how much power is produced. Therefore, geothermal power plants are quite effective in supplying the baseload energy requirement.
Real power output is relatively near to total installed capacity in geothermal power plants, which have a high capacity factor.
In 2017, the average power output around the globe exceeded 80% (capacity factor) of the total installed capacity, but as much as 96% of that capacity has been utilized.
5. Great for heating and cooling
For the power-generating turbines used in geothermal energy to work efficiently, the water must be heated to a temperature of at least 150°C (approximately 300°F).
Geothermal energy can also be used for heating and cooling, which is a simpler application. The (quite minor) temperature difference between a ground source and the surface is exploited in this method.
Seasonal temperature variations are often more difficult to affect the earth than the air. Therefore, a geothermal heat pump can use the ground just a few feet below the surface as a heat sink or source, similar to how an electrical heat pump uses the heat in the air.
In the past few years, geothermal heating and cooling has become increasingly popular among homeowners.
Disadvantages of geothermal energy
1. Environmental issues
Under the earth’s surface, there are a lot of greenhouse gases. Some of these gases escape when geothermal energy is used, traveling to the surface and entering the atmosphere. Near geothermal power facilities, these pollutants are typically more prevalent.
Sulfur dioxide and silica emissions from geothermal power facilities are negligible. Mercury, arsenic, and boron are only a few of the harmful heavy metals that may be present in the reservoirs.
Despite this, the pollution produced by geothermal energy is extremely low and pales in comparison to that of coal and other fossil fuels. The Union of Concerned Scientists also reports that there have been no occurrences of geothermal site water contamination in the US.
2. Surface instability (earthquakes)
The stability of the soil may be impacted by the construction of geothermal power facilities. In fact, both Germany and New Zealand have experienced subsidence (sinking of the Earth’s surface) as a result of geothermal power facilities.
Hydraulic fracturing, a necessary component of creating enhanced geothermal system (EGS) power plants, can cause earthquakes.
An earthquake with a Richter magnitude of 3.4 occurred in Switzerland in 2006 as a result of the construction of a geothermal power plant.
3. Expensive
The cost of commercial geothermal energy projects is high. A geothermal power station with a capacity of 1 megawatt typically has installation costs that range from $2.5 to $5 million (MW).
The discovery and drilling of new reservoirs contribute significantly to cost growth and generally account for 50% of total expenses.
As was already established, the majority of geothermal resources cannot be used profitably, at least not with the level of technology, subsidies, and energy prices that exist today.
Geothermal heating and cooling systems for households and commercial buildings have high upfront expenses. Nevertheless, these systems should be viewed as long-term investments because they are probably going to save you money in the future. Ground source heat pumps typically range in price from $15,000 to 40,000 when installed, with a 10–20 year payback period.
4. Location-specific
Reliable geothermal reservoirs are difficult to find. Some nations are endowed with abundant natural resources; for instance, the Philippines and Iceland use geothermal energy to supply almost one-third of their electricity needs.
Significant energy losses must be considered when transferring geothermal energy over large distances using hot water rather than electricity.
5. Sustainability issues
Over millions of years, rainwater seeps into the geothermal reservoirs via the earth’s surface. According to studies, if the fluid is taken quicker than it is supplied, the reservoirs may get empty.
After the thermal energy has been used, efforts can be made to inject fluid back into the geothermal reservoir (the turbine has generated electricity).
Geothermal energy may be sustained if reservoirs are maintained properly. Since home geothermal heating and cooling uses geothermal energy differently than geothermal power plants, this is not a problem.
Key takeaways
- Geothermal energy is derived from the massive amount of heat that exists under the Earth’s surface.
- Geothermal energy can be used to generate electricity by drilling underground and tapping into the heat to operate steam turbines on the surface.
- Geothermal can also be used for heating and cooling by taking advantage of the temperature differences above and below the ground.
- Pros of geothermal energy: it’s environmentally-friendly, renewable and sustainable, reliable, great for heating and cooling, and has massive potential.
- Cons of geothermal energy: generates waste, reservoirs require proper management, it’s location-specific, has high initial cost, and can cause earthquakes in extreme cases.
- Geothermal has the potential to become a major global energy source, but is held back by its high upfront costs.
