What are the 10 advantages of geothermal energy?

What are the 10 advantages of geothermal energy_featured image

10 advantages of geothermal energy are:

  1. It is renewable.
  2. Environmentally friendly.
  3. It is reliable.
  4. There is a massive reserve of energy.
  5. Low emissions.
  6. Versatility – many uses.
  7. It can be used on different scales.
  8. It’s good for the economy.
  9. No fuel is required.
  10. Job creation.

What is geothermal energy?

Geothermal energy is a type of energy that is harnessed from the earth’s heat. Below the earth’s crust, the interior gets progressively warmer as you approach the centre. In general, the temperature increases by at least 25°C (45°F) for every kilometre that you dig down towards the planet’s core.

Geothermal energy works by either harnessing this heat to create steam, and in turn electricity, or channelling the heat for domestic or industrial purposes. In some situations, it is also possible to use it for cooling.

In this article, we’re going to look at the 10 main advantages of geothermal energy. We’ll also look at how it is created, whether it is renewable and what it is used for.

Video – Geothermal Advantages and Disadvantages

 

How is geothermal energy created?

It is thought that most of the earth’s inner heat was actually generated during the planet’s formation and is slowly radiating out from the core. That said, within the mantle of molten rock there is also a type of heat generation called frictional heating. This is a result of more solid parts sinking towards the centre and creating friction as they travel.

To use this heat to generate electricity, we drill down into underground reservoirs of hot water and channel it up towards a turbine. Whilst underground this water is in a liquid state because of the higher pressure. When it reaches the surface, however, it turns to steam. This steam can then be used to power a turbine and generate electricity, much like in a traditional coal power plant.

For heating buildings, we harness geothermal energy in a slightly different way. Pipes are laid below the building through which water or a liquid run. A pump can extract the heat from these pipes and then circulate it.

Is geothermal energy renewable?

Geothermal power is considered a renewable energy source. Heat from the centre of the earth dissipates extremely slowly due to the size and density of the planet’s outer layers. When you dig deep enough to access this heat you get an almost unlimited supply of energy without using fossil fuels.

All in all, it is extremely unlikely that this heat will run out. In fact, some scientists believe it would take upwards of 90 billion years for this to happen. Such constant heat generation makes geothermal energy both extremely reliable and highly energy efficient.

Table – 10 examples of non-renewable resources

Non Renewable Resource

How much is left?

When will it run out?

Natural gas

7124 trillion cubic feet (tcf)

40 years (2060)

Crude oil

1.65 trillion barrels

40 years (2060)

Minerals

1000 trillion tons

500 years (2520)

Coal

1.1 trillion tons

70 years (2070)

Water

14000 cubic kilometres

Shortages in 2030

Topsoil

10 cms

60 years (2060)

Sand

Not known (15billion tons used/year)

Not known - in short supply

Biomass

304 trillion trees left

Not known

Fish

80 million tons fishes each year

30 years (2050)

What is the most efficient renewable energy?

Most sources agree that when you factor in costs, maintenance and environmental impact, wind is the most efficient renewable energy source. Nonetheless, geothermal is a close second, beating both hydropower and solar. Both wind power and geothermal are also more efficient and safer than nuclear power or fossil fuel-based power.

What are the advantages of geothermal energy?

Geothermal energy has a number of tangible advantages, despite still being only a minor player in worldwide energy production. Let’s look at the top 10 advantages of this green but highly underutilised energy source.

The top 10 advantages of geothermal energy

  1. It is renewable. The supply of heat from the earth’s core will be stable for the rest of human history.
  2. Geothermal energy is more environmentally friendly than non-renewables. Its above ground installations are less damaging to ecosystems than hydropower.
  3. It is reliable. Earth generates heat at a slow and steady pace – there are no sharp seasonal variations that could hurt supply, unlike solar or wind, for example.
  4. There is a massive reserve of energy. The earth’s heat is so intense, and the interior so vast that there is an almost limitless supply of geothermal energy.
  5. Low emission generation. Once a geothermal plant is constructed, emissions are extremely low, giving it a small carbon footprint.
  6. Versatility. Geothermal can be used both for direct heat supply and electricity generation.
  7. It can be used on different scales. You don’t have to build a whole power plant to harness the earth’s heat. In fact, you can harness it for geothermal heating of individual homes or small communities.
  8. It’s good for the economy. When you create green power domestically, it means you don’t have to import fossil fuels from elsewhere. Fuel independence is an important aspect of a free and self-reliant economy.
  9. No fuel is required. One of the main reasons that geothermal power is better for the environment is that it doesn’t rely on fossil fuels. This eliminates both cost and air pollution.
  10. Job creation. The construction of geothermal plants can create jobs in areas that were otherwise underdeveloped and help counter rural deprivation.

What is the biggest single advantage of geothermal energy?

Geothermal energy’s single biggest advantage is how incredibly reliable it is. Wind energy and solar power are also green and renewable, but they are subject to daily and yearly variations in abundance. Geothermal, on the other hand, is a constant supply of energy, and will be for the foreseeable future.

Moreover, where geothermal electricity production relies on underground water, those reservoirs can be topped up if pressure begins to drop. Some regions have even begun using treated wastewater for this purpose.

Table – Advantages and Disadvantages of Geothermal Energy

Geothermal Advantages (Pros/benefits)

Geothermal Disdavantages (drawbacks/cons)

Low running costs once established

High installation & surveying costs (investment)

Low carbon footprint (38 gms CO2/kWh)

Machines needed to extract and convert heat

Low ecological impact

Above machines made by fossil fuel energy

Renewable and sustainable

Can cause minor earthquakes

Generate electricity cleanly

Location dependent to some extent

Heat buildings directly

Deep drilling needed for high temperature plant (higher temp. = higher efficiency)

Flexible agricultural use 

Possible release of greenhouse and toxic gases

Disadvantages of geothermal energy

As with hydropower, geothermal energy has a high initial cost due to the technologically advanced nature of geothermal power plants. Generally speaking, this cost is between $2500 and $5000 per KW installed. Pipeline drilling can be costly before work on the turbine and generator have even been planned.

Furthermore, geothermal energy is not suitable for all locations. To make a site viable for a geothermal electricity plant, there needs to be a good reservoir of water, preferably with a temperature of at least 98°C (210°F). The water should also have a low gas and solid content.

Another disadvantage is that, like fracking, the construction of a geothermal plant can cause small earthquakes. This increases community opposition and red tape. At the same time, the drilling can on occasion contaminate water supplies.

Geothermal not a pollutant

Can geothermal plants emit pollution?

Does geothermal energy cause pollution?

When completed, geothermal heat distribution pumps are small and generate no emissions. Geothermal power plants also occupy relatively small areas above ground when compared with others. They let off negligable amounts of greenhouse gas (mainly CO2) and have no need to use fossil fuels.

All in all, the environmental impact of any geothermal installation in incredibly low. It would be fair to say this energy source actually lowers pollution by replacing fossil fuels.

Table – emissions of geothermal power plants compared to other energy sources

Generating Plant - energy used

CO2 Emmissions

Geothermal

38 gms CO2/kWh

Solar

50 gms CO2/kWh (includes solar panel manufacture)

Wind turbines

11 gms CO2/kWh

Hydropower

27 gms CO2/kWh

Nuclear

4 gms CO2/kWh

Coal

915 gms CO2/kWh

Gas

190 gms CO2/kWh

What is geothermal energy used for?

Obviously, the most economically important usage for geothermal energy is to create electricity. This electricity enters the grid and helps meet the demands of the local population.

Such large installations are not the only way that geothermal can be used, though. Given its versatility, geothermal heat can be channelled through pumps to simply provide warmth. In this scenario, no water reservoir is needed.

For small communities, factories, and small industrial buildings, geothermal pumps can be a worthwhile investment. Small heat pumps are also becoming widely used in privately owned houses, with companies in both the US and Europe specialising in building them. It is worth noting, however that this is a long-term investment – a heat pump for just one home may cost over $10000.

Another use for geothermal heat is in agriculture. Greenhouses in particular are excessively expensive to heat during adverse winter weather. Using geothermal energy, farmers can produce crops during even the coldest months of the year.

Can geothermal be used for cooling?

Geothermal energy can just as efficiently be used for cooling. Using the same pump and pipe system that is generally installed for heating, you can send heat down from a building and into the ground, instead of the other way around.

By doing this, you effectively gain cheap and efficient air conditioning from exactly the same apparatus that heats your home.

For example, during the summer the ambient temperature in home could climb to 27°C (80°F) or higher but it will still be a mild 13°C (55°F) at the depth that most heat pumps are installed at.

Where is geothermal energy most used?

As we discussed earlier, geothermal energy exploitation is not suitable for all locations. To create electricity, it needs a reservoir of water. That reservoir needs to be reasonably close to the surface so that drilling isn’t excessively expensive or technologically difficult. If it is more than 1 or 2 miles below the surface, then the location is not viable. It also needs to be located in an area where the rock is permeable enough to drill through.

Last but not least, geothermal installations are much easier to build on private land, as this lowers costs associated with various permits and red tape.

In the US, most geothermal power plants are located in the western states where these conditions are met. California, for example, has been producing geothermal electricity since the 1960s and produces more than any other state. The island of Hawaii also meets about 30% of its electricity demands with geothermal energy.

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