In dictionary terms, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object. However, in practical terms, it a life-sustaining resource without which humans cannot survive. There are various types of energy, depending on their source and their nature. One type of energy is renewable energy. A renewable form of energy is geothermal energy. Like all other forms of energy, it has its own advantages and disadvantages.
WHAT IS RENEWABLE ENERGY?
As the name suggests, renewable energies are forms of energy that can be renewed. This means that their supply is unlimited. It can also mean that its supply replenishes at a rate faster than that of its consumption. The most common examples include wind, solar, geothermal, biomass, and hydropower. They do not harm the environment by releasing carbon emissions. Hence, renewable energies are also often referred to as “green energies” or “clean energies”. This doesn’t mean that these energies aren’t harmful to the environment and have zero impact. Some of them do contribute to the harm caused to the environment. Although, this contribution is drastically low when compared to fossil fuels.
Most renewable energy is derived directly or indirectly from the sun. Sunlight can be captured directly using solar technologies. The sun’s heat drives winds, whose energy is captured with turbines. Plants also rely on the sun to grow and their stored energy can be utilized for bioenergy. Not all renewable energy sources rely on the sun. For example, tidal energy relies on the gravitational pull of the moon, and hydropower relies on the flow of water.
Geothermal energy is a form of renewable energy.
WHAT IS GEOTHERMAL ENERGY?
The word geothermal is made up two words, geo + thermal. “Geo” means earth and “thermal” means heat. It is the energy derived from the heat trapped under the Earth’s crust. This heat is contained in the rock and fluid that fills the fractures and pores within the rock of the Earth’s crust. It can be found as magma, the hot molten rock under the surface of the Earth.
HOW IS IT OBTAINED?
a geothermal power plant, wells are drilled 1 or 2 miles deep into the Earth to pump steam or hot water to the surface. These power plants are found in areas with a lot of hot springs, geysers, or volcanic activity. This is because these are places where the Earth is particularly hot just below the surface.
There are 3 types of geothermal power plants, dry-steam power plants, flash steam power plant, and binary cycle power plants. Enhanced geothermal systems are also used to generate power.
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Dry-steam power plants are the oldest type of geothermal power plant. They utilize underground sources of steam, which are piped directly into the plant. This steam then turns turbines, which in turn generates electricity. The Geysers in California are one of the largest geothermal energy complexes in the world. They provide about a fifth of all renewable energy in California.
The most common of geothermal power plants are flash-steam power plant. They use underground sources of steam as well as hot water. Water is pumped into a low-pressure area, and it sometimes evaporates rapidly into steam. This steam/water is funnelled out to power a turbine and generate electricity.
Binary cycle power plants heat water underground, which is then used to heat a liquid organic compound. The organic liquid creates steam, which flows through a turbine and powers a generator to create electricity. The water is recycled back to the ground. The Earth heats it up, and it can be used again.
Advantages of Geothermal Energy
One of the biggest advantages of geothermal advantages is that it is eco-friendly. It does not contribute a lot to pollution and helps in creating a clean environment. Geothermal energy is extracted from the earth without burning fossil fuels, and geothermal fields produce practically no emissions. It would be a lie to say that geothermal power plants do not release any harmful emissions. An average geothermal power plant releases the equivalent of 122 kg it generates. However, the carbon emissions of a geothermal power plant are drastically low when compared to fossil fuels. 122 kg CO2 for every megawatt-hour (MWh) of electricity generated is one-eighth of the CO2 emissions associated with typical coal power plants.
No Subsequent Costs
Once the plant has been installed, the resource does not have to be mined or transported any further.
Out of all major power sources, geothermal energy requires the smallest amount of land. Hence, it has the smallest land footprint.
StableVarious renewable sources of energy are dependent on the availability of a certain resource. For example, solar energy requires sunlight. Hence, it can only be harnessed during the day. However, geothermal energy can provide a constant supply of power, regardless of external factors
It can be used to provide baseload or peak power as and when needed.
Another very important advantage of geothermal power is that its plants operate silently. They utilize the hot steam or water coming from the Earth to power turbines. This does not create any noise. On the other hand, renewable energy sources such as wind energy create a lot of noise. Wind turbines make a lot of noise which can be disturbing and harmful for human and non-human life in and around the wind farm. The sounds they produce are typically foreign to rural settings where wind turbines are most often used.
Disadvantages of Geothermal Energy
High Installation Costs
Although it is a one-time investment, geothermal energy can burn quite a big hole in a customer’s pocket. Initially, drilling wells is extremely expensive. Furthermore, the cost is increased even more because of the installation of a cooling system and a heating system. The cost of installing a geothermal heat pump in a basic home ranges from $10,000 to $20,000. However, the return on investment is considerable and a geothermal system can recover the installation cost in 5 to 10 years. Hence, the investment does yield returns, but it takes a long period of time for that to happen.
Greenhouse Gas Emissions
Even though it is considered a clean fuel, geothermal energy does carry a risk of emitting greenhouse gases. Greenhouse gases such as hydrogen sulphide, carbon dioxide, methane and ammonia are trapped in large quantities under the surface of the Earth. Drilling into the Earth in order to harness or extract geothermal power can result in these gases migrating to the surface and then to the atmosphere. These kinds of emissions are prevalent and higher where geothermal energy power plants are situated and are linked to silica and sulphur dioxide emissions. Additionally, the reservoir may contain toxic heavy metals such as arsenic, boron, and mercury. However, the amount of gas released is significantly lower than in the case of fossil fuels.
Geothermal energy can be harnessed round the clock. However, it can only be done in certain places. Sites that are suitable for geothermal power plants are generally far off from cities. However, Even after a location has been found with a sufficient amount of underground steam, it is not a guarantee that a plant can be constructed there. It must have the right type of hot rocks. The rocks should be at a reasonable depth and soft enough to drill through.
Pros and Cons of Geothermal Energy
|High installation costs|
|No subsequent costs||
Greenhouse gas emissions