to heat and cool our buildings, and in some cases, to provide hot water. This stable energy resource should continue to exist as long as the earth’s core stays hot. Geothermal power does have its advantages as well as its disadvantages, however.
Advantages of geothermal energy
Well-established technology with great potential
Modern geothermal energy technology has been around since 1969, so it is a proven form of energy generation. With a global potential of 2 terawatts (TW), there are many opportunities to obtain more of our energy from this source.
With a 500% efficiency rate, geothermal energy is extremely energy-efficient, far surpassing the efficiency of furnaces and boilers. This type of energy can be used to provide energy for a range of building sizes, including large and small buildings and residences. As geothermal technology has improved, it has become increasingly more efficient and affordable.
Good long-term investment
Although both commercial and residential geothermal systems require a large up-front investment, the energy that is generated from them is free, and therefore allow for an efficient payback. When return on investment is considered, residential geothermal systems do not cost much more than conventional heating and cooling systems.
In some countries and municipalities, tax credits are offered to residents and businesses to build these energy systems.
Renewable and no fuel required
Since geothermal energy comes from the earth and requires no outside fuel to generate it, it is considered to be a renewable energy source.
Stable and predictable energy source
Unlike solar and wind energy technologies, the even temperature of the earth is consistent and predictable despite variable weather conditions, and supports stable energy prices. Geothermal energy is also much better at meeting base load energy demand than solar and wind energy technologies do.
Less environmental impact
While some pollutants and emissions are generated through the use of geothermal energy, the quantities generated are significantly less than those generated through the use of fossil fuels.
Small land footprint
Since geothermal systems are built mostly underground, they require a minimal area of land for their construction.
Geothermal energy can be found everywhere on earth, but some locations have a much larger geothermal energy reserve than others. For example, locations with high geologic activity, such as Iceland and the Philippines, are ideal places to build geothermal energy systems.
Disadvantages of geothermal energy
Shortage of qualified installers
In many locations, it may be difficult to find professionals that are trained to install residential geothermal systems.
Specific site requirements
Some types of underground rocks are much easier to drill through than others, making some sites less amenable to geothermal drilling. To make the investment worthwhile, there must also be significant geologic energy reserves at a particular site to effectively produce electricity.
Some negative environmental impacts
Greenhouse gases located below the earth’s surface can escape into the atmosphere when geothermal drilling occurs. This effect is worse near geothermal power plants. Other environmental pollutants such as sulfur dioxide, silica emissions, and heavy metals can also escape into the environment as a result of drilling. However, this pollution is much less than the pollution that is produced through the use of fossil fuels.
Geothermal plants can cause earthquakes
Because geothermal plants use hydraulic fracking to obtain energy from below the surface of the earth, this process affects the stability of land. This can lead to some subsidence effects and earthquakes.
High initial costs
Because the costs of construction of geothermal energy systems and plants are high, geothermal energy systems require a long-term investment strategy. The cost of commercial plants can range from $2-$7 million, and a residential ground-source heat pump is about $3,000-$10,000 with a payback of 10-20 years. It is especially expensive to build plants that convert hot water and steam into electricity.
Energy loss during transport
Significant energy losses occur if hot water is used to transport the geothermal-generated energy long distances from geothermal plants.
Reservoirs need proper management
Geothermal energy is only sustainable if the reservoirs are properly managed. If they are overused, geothermal energy reservoirs can be depleted much faster than they are replaced. To help mitigate this issue, plants can inject fluid back into the reservoir after the geothermal energy has been used and made into electricity. Since residential systems use geothermal energy in a different way than power plants do, this issue does not apply to them.
As with other forms of renewable energy, the implementation of geothermal systems depends upon the state of the technology, energy prices, and support from local and national governments.