Thanks to long-lasting, safe, reliable plants, geothermal energy is increasingly low risk and brimming with untapped potential. It is silent, always available, has little impact on the landscape and is versatile. It can even be used for cooling and creates more jobs than any other green energy.

Just a few kilometers beneath our feet lies enough energy to potentially meet all of humanity’s requirements. It is the energy of the Earth’s own heat. While it still plays a marginal role in the world energy scene, it may yet become one of the protagonists of the energy transition to green sources.

Geothermal energy shares many of the advantages of most other renewables. For instance, compared to traditional thermoelectric stations powered by fossil fuels like coal, it produces less carbon dioxide, particulate matter and other toxic substances that create the greenhouse effect, which contributes to climate change. Using this underground energy allows us to reduce our use of fossil fuels and can help us to achieve energy self-sufficiency. Geothermal energy is also in line with sustainable developmentand is essentially free once the planthas been installed. There is no doubt either that recent history has taught us that both the performance and efficiency of renewable plants are improving year after year.

Unlike the sources we have encountered thus far, geothermal energy has certain characteristics that set it apart from other renewables such as wind, solar and hydroelectric power. Below is a 10-point summary that demonstrates why the natural heat below the Earth’s surface still has huge potential to become one of the protagonists of the energy sector of the future.  

1. Always available 

Aside from being essentially unlimited like many other renewables, geothermal energy is always available. It is not impacted upon by whether it is day or night like solar energy, and does not depend on season, climate or weather conditions like wind and solar power. On average, a geothermal power plant will produce energy for around 8,600 hours a year, while in solar plants the average is around 2,000 hours per year. We can therefore describe the rate of geothermal energy production as constant, at least in the short or medium term. This makes it more easily predicable and plannable.

2. Doesn’t require large spaces

Unlike the majestic expanses of large wind turbines and photovoltaic panels, geothermal power plants only require modest amounts of space. Regardless of whether it is a domestic system or a large-scale plant, most of the components (including the heat exchangers) are buried underground, with very little remaining above ground. In homes, the heat pump is about the size of a household appliance, while in larger plants, the biggest components are the cooling towers, followed by turbines. In certain cases, the plants can have a visual impact on the landscape but newer architectural designs are mitigating this issue.

3. Silent energy

At least while functioning at full capacity, geothermal power plants produce negligible and imperceptible noise levels. During the construction phase of the plants – including excavations – a certain amount of noise is inevitable, but once construction is complete, everything is silent. This applies to both domestic systems and outside larger power stations that have at most several turbines spinning.  

4. It creates record numbers of jobs

That is what the data gathered by the energy services manager, GSE, tells us: for the same installed power, geothermal energy creates more indirect employment than any other type of renewable. In terms of numbers, that translates to 34 jobs per installed megawatt, much higher than the 19 created by wind power and the 12 by photovoltaic energy. In Italy alone, 2,000 gigawatts of installed power would guarantee permanent employment for 4,000 people and 30,000 other jobs.

5. Provides more energy for the same nominal power

Because delivery is constant, geothermal energy can work at full capacity non-stop (maintenance aside). This means that the resulting amount of energy will be the equivalent of the power multiplied by the hours of use. This is very different to photovoltaic, hydroelectric and wind systems, which only rarely work at full capacity. So more energy is produced for the same nominal power.

6. Allows double recycling

Geothermal power optimizes resources. On the one hand, the plants have components that can be salvaged and reused at the end of the installation’s lifecycle. On the other, during operation, the flows are organized in such a way as to put any heat that can’t be used immediately back into the circuit using the steam pipes that power the plant, helping to save energy.

7. The plants are long-lasting, safe and reliable

Both domestic and large scale plants have very long average life spans – up to 80 to 100 years. This is extraordinary longevity compared to a domestic boiler, which normally lasts around 15 years. The fact that there are no fuels involved also means there is no risk of fire, and the long experience we have gained with this type of system guarantees excellent reliability.

8. Requires very little maintenance

Particularly when it comes to domestic use, geothermal plants do not require any special maintenance. As they are closed systems, the pressure of the fluid in the piping self-regulates, and the number of electrical and mechanical elements that can break down is also very small.

9. The Earth’s heat can also cool

When geothermal energy is mentioned, we think first and foremost of thermal energy and heating. Nonetheless, geothermal plants are designed to both heat and cool. This is why, aside from in the large stations, geothermal power systems can be installed in almost any type of building: from homes to shopping malls, public buildings and sports centers. The only limit being, of course, that the location is favorable in terms of the characteristics of the Earth’s crust.

10. More advantages for the home

In addition to providing air conditioning in the summer and heating in the winter, geothermal energy has many other advantages when used in the home. For instance, it reduces overall energy consumption by between 30 and 70% because it can also do the job of a boiler, i.e., heat water for use in the kitchen and bathroom.

Bio-architectural and low temperature outlook

Thus far, geothermal power has only been of very marginal significance on the world energy scene. Even though it is hard to predict that it will outstrip other renewable sources – in part because of the issue of reaching the underground heat – innovation is helping to solve more and more of geothermal energy’s intrinsic problems.

The risk of such plants negatively impacting the landscape is also reducing, thanks to bio-architecture solutions which integrate them into the surrounding natural environment and use non-polluting materials. The classic unpleasant odor that used to hang around plants has now also been eliminated using filtration and containment systems that prevent smells from beneath the earth escaping.

Even the need for high temperatures of at least 150°C required at depth is becoming less of a problem. This is thanks to low-enthalpy solutions which allow temperatures to drop as low as 100°C and beyond, while within a decade or two, that should go down to under 90°C. This in turn will significantly boost the number of locations in which geothermal power could become a reality. 

Source: Enel Green Power

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