Can geothermal energy help counteract climate change?

Yes, like all the other sources of green energy. Geothermal plants don’t produce greenhouse gases, unlike conventional power plants that use fossil fuels like coal, oil, or gas. Even though there might be some gas emissions from the ground (95% of which is carbon dioxide mixed into geothermal fluids), today’s technology makes it possible to contain the vast majority of these substances, preventing them from being released in the atmosphere. According to a European Union report, every kilowatt-hour of geothermal energy saves 260 grams of CO2 compared to a gas-fired plant, 705 grams compared to an oil plant, and 860 grams compared to a coal-fired plant. The International Energy Agency (IEA) calculated that 92 terawatt-hours of geothermal energy were produced worldwide in 2019; moreover, in the United States alone, geothermal plants are estimated to avoid the emission of greenhouse gases equal to 4.1 million tons of carbon dioxide a year.

Are investments in geothermal technology growing?

Yes, there is a growing trend around the world. According to the European Geothermal Energy Council (EGEC), for instance, the number of active geothermal plants could double in the next five to eight years. The interest in investing in renewables also concerns geothermal energy because it can be developed in almost every country in Europe and in many others around the world, from the United States to Indonesia, from Japan to Kenya. Based on growth figures, which saw a 5% increase in 2019 compared to the previous year, and considering its untapped potential, the 2020s are expected to go down in history as the decade of geothermal energy. It is estimated that between 2020 and 2025, investments worldwide will experience an average annual growth of 3.5%, with investment levels comparable to other sources of green energy. North America will dominate the expansion until 2025.

Does geothermal energy help rural economies?

Yes, it does. Many scientific studies confirm it: whether it is used to generate electricity or for heating, geothermal energy contributes to the development of rural economies and has positive impacts at a local level in the areas where the power plants are located. The main benefits are social, industrial, economic and in terms of employment, and are particularly prominent in rural, mountainous, and remote areas. Furthermore, geothermal energy can be used to heat agricultural greenhouses or aquaculture systems, as well as to provide power to industrial plants and heating systems. When combined with other green energy sources, geothermal energy can generate even more substantial effects.

Does geothermal energy create new jobs?

The construction and operation of geothermal plants requires several different specialized skills. Aside from geologists and earth science experts, the geothermal sector also creates jobs similar to other green energy fields, like scientists, environmental experts, geographers, and a large number of electrical, mechanical, and civil engineers. In addition, it employs a series of other specialists in charge of geologic surveys, drilling, and building the plants. There are also indirect jobs pertaining, for instance, spa resorts and aquacultures: according to the US Department of Energy, geothermal plants generate a virtuous cycle for employment that positively affects many different areas. While it is challenging to determine the exact number of people employed in the geothermal sector, the International Renewable Energy Agency (IRENA) estimated that 160,000 people worked in the industry in 2015. An increasingly rapid job growth was already expected at the beginning of this century, but the data from the United States alone (35,000 employees in 2019, according to the IRENA) indicates that it is going even better than anticipated. Finally, installed power being equal, geothermal energy is the type of renewable source that has the largest induced employment: 34 jobs per megawatt installed, compared to 19 for wind power, and 12 for photovoltaic energy.

What benefits does a geothermal plant bring to the local area?

The presence of a geothermal plant has positive effects on the local area and its economy, in terms of both job creation along the entire supply chain and induced employment generated throughout the various phases of the project: from early development, to building the systems, to running and maintaining them. Moreover, it also makes it possible to reduce energy imports and get closer to energy self-sufficiency. The continuous supply of heat coming at a constant rate from underground allows to forecast and plan energy supplies, and a geothermal system can also provide cooling in many kinds of buildings. Finally, it can cut a home’s energy consumption by between 30% and 70% because it can heat the water used in the kitchen or bathroom.

Is there enough geothermal energy for everyone?

There is an enormous amount of energy underground: extracting just a small fraction of it would be enough to meet the global demand. As a matter of fact, just the first 10,000 meters of the Earth’s surface contain 50,000 times more energy than all oil, gas, and coal deposits worldwide. Even though this energy is not distributed uniformly around the globe (since it is easier to extract near volcanically active areas), we are currently tapping into a very small part of this potential.

Are there energy subsidies for geothermal power?

All forms of energy (including oil, gas, coal, nuclear, and renewables) receive, or can receive, public incentives. On average, fossil fuels have obtained significantly more incentives compared to renewable sources. According to the Nuclear Energy Institute (NEI), 70% of all energy subsidies from 1950 to 2016 went to fossil fuels in the form of tax concessions and other programs. By contrast, green energy only received 17%, and the geothermal sector got a meager 1%. Most of the funds received were spent to incentivize research and development activities.

Can a geothermal plant offset the emissions generated by its construction?

A wealth of scientific publications covers the overall balance of the carbon footprint created by geothermal plants. What is certain is that geothermal energy entails a considerable reduction of emissions compared to fossil fuels; the picture, however, is more complex when we compare it to other sources of green energy. The power plants’ construction phase, indeed, has to account for the construction of the buildings themselves as wells the energy required to drill and reach the heat source underground. Nevertheless, the signals emerging from quantitative analyses are clear. Over the course of a geothermal plant’s lifecycle, a few dozen grams of carbon dioxide are released in the air for every kilowatt-hour of energy produced; depending on the studies and the kind of plant technology, this amount can vary from 15 to 180 grams per kilowatt-hour. There is no comparison between geothermal and fossil sources: in the early 2010s, natural gas released on average 469 grams per kilowatt-hour, oil emitted 840, and coal a staggering 1,001. Even if technological progress is slowly lowering these values, geothermal energy still ensures a definitely greener performance.

What is the average lifespan of a geothermal system?

Whether it is a domestic installation or a large-scale plant, the average service life of geothermal systems is very long. The exact numbers vary somewhat: heat pumps generally last 15 to 20 years, while the benchmark lifecycle for larger power systems is 30 years. In reality, however, many systems last over 60 years, while plants that were built more recently can function up to 80-100 years. This extraordinary longevity is due both to the experience accrued with these technologies and to the lack of combustion, which eliminates the risk of fires. Geothermal systems require relatively little maintenance, and the less lasting components can usually be replaced when they reach the end of their life.

What kind of waste is generated by the construction of a geothermal plant?

Digging the wells creates the most significant waste, because it generates drilling muds, soil, and rocks. Recycling systems, non-polluting additives, and containment tanks are used to prevent ground contamination and reduce sludge production. All the other kinds of waste (from packaging material to rubber and wood) are generated in very small quantities and the vast majority can be recycled. Even the various components of the power plant can be salvaged and reused at the end of their installation lifecycle.

How long does it take to recover the initial investment?

The exact time frame depends on the potential incentives received but, in any case, is much shorter than the lifespan of a power plant, which lasts for several decades. Depending on the presence of funding and the system’s characteristics, estimates vary from a minimum of four years to a maximum of ten. The initial investment is largely recovered, and the actual cost of the energy produced becomes progressively lower thanks to new heat collection technologies.

Is geothermal energy convenient?

The conversion of underground heat into electricity has already reached satisfactory performance levels, with efficiency generally ranging between 33% and 50%. Over time, geothermal energy will become increasingly more accessible, available, and competitive compared to other renewables. During the 2010s, the overall cost of a kilowatt-hour of geothermal energy was already between 0.10 and 0.20 euros, not factoring in any incentives and deductions. Finally, geothermal is a kind of energy that optimizes resources: the heat that cannot be used immediately is put back into the system, enhancing energy saving.

How much noise does a geothermal system make?

When in full function, geothermal systems make a negligible amount of noise: large power plants emit as much noise as a vacuum cleaner, while home systems are significantly quieter. A certain amount of noise is inevitable during the construction phase (which includes subsurface exploration, drilling, and building), but once that is over everything goes quiet. This applies to both home systems and outside large power plants, which have a few turbines in motion at most.

How much space does a geothermal system take?

Unlike the grandeur of wind turbines and the extensive fields of solar panels, geothermal energy requires little space. Whether it is a home system or a large-scale power plant, most of the components (including the heat exchangers) are underground, and very little remains above the surface. A heat pump for a home is as big as a household appliance. As for a power plant, the most imposing parts are the cooling towers, followed by the turbines.

Can geothermal plants ruin the landscape?

While in operation, geothermal plants have a very low visual impact on the landscape, most of which is determined by aboveground structures like the building itself and the steam pipes. A lot can be done nowadays by taking architectural features into consideration: the risk of compromising the landscape is increasingly mitigated by bioarchitecture solutions, which integrate the structures into the natural environment and use non-polluting materials. During construction, the presence of moving vehicles and equipment, excavation operations and all the activities required to prepare the area for the power plant are inevitable. During this transitional phase, the area looks like a typical construction site, which, by the way, can also attract curiosity in and of itself.

Do geothermal plants emit unpleasant smells?

Infinitely less than in the past. The unpleasant odor traditionally associated with geothermal energy and thermal water is due to the hydrogen sulfide (H2S) underground. Nowadays, all power plants have an abatement system for hydrogen sulfide, which blocks around 99% of emissions thanks to its filters and containment technologies. The small remaining part can be released into the air by the cooling towers, and rarely passes the odor detection threshold for even the most sensitive noses (set at 4 micrograms per cubic meter). Larger concentrations are released only in case of exceptional circumstances and, even then, they still remain abundantly below the tolerable limit set by the World Health Organization (150 micrograms per cubic meter).

Does geothermal energy pose a risk to human health?

No, as long as all safety and mitigation measures are followed correctly. Safety measures concern anything that could put power plant workers at risk, while mitigation regards the containment of possible emissions. Nowadays, all substances that are potentially harmful to human health are contained at a rate that varies between 80% and 99%, and the reduced emissions ensure that air quality is unaltered. Furthermore, the transition towards renewable energy (supported by the geothermal sector) avoids the emission of additional greenhouse gases and other air pollutants connected to public health problems; moreover, it also reduces water consumption compared to the amount often needed to run fossil fuel power plants.

Frequently asked questions about geothermal energy

There is an enormous amount of energy underground. Thanks to a still untapped potential, the 2020s are expected to go down in history as the decade of geothermal energy. It is a power source that optimizes resources: the heat that cannot be used immediately is put back into the system, thereby enhancing energy saving. Here are all the answers to fulfill your curiosity about this renewable energy source.

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