Geothermal energy It has become one of the most attractive alternatives in the world of renewable energy, but it still remains largely unknown to many households in Spain and much of the world. The possibility of harnessing the heat beneath our feet to heat homes, produce hot water, or even cool them in the summer, is arousing more and more interest for those seeking to reduce their energy bill and contribute to the sustainability of the planet.
However, not everything surrounding geothermal energy is perfect or universally applicable.. Despite its notable advantages and potential savings, There are technical, economic and geographical aspects that must be assessed. Before installing a geothermal system at home, consider this technology. Is it really worth investing in? What are its real pros and cons for domestic use? Below, we explain in detail how it works, what types exist, their requirements, and, above all, their strengths and weaknesses, so you can assess whether it's the ideal renewable energy for your home.
What is geothermal energy and how does it work?
Geothermal energy harnesses the heat stored in the earth's subsoil. for various domestic and industrial applications. This heat is generated by the planet's thermal gradient: the temperature increases between 2 and 4°C for every 100 meters of depth, due to the heat flowing from the core to the Earth's crust.
In homes and buildings, the most common way to take advantage of geothermal energy is to install heat exchangers underground (either horizontally, vertically or in groundwater collections) and a geothermal heat pump which carries out the temperature exchange between the house and the subsoil. This allows for efficient and clean heating in winter, cooling in summer, and domestic hot water (DHW). The system operates in a closed circuit, avoiding pollution and using a minimal electrical input to circulate the heat transfer fluid.
One of the highlights of the domestic geothermal energy es que the subsoil temperature is much more stable than that of the outside air, which makes the geothermal heat pump the system most efficient currently available to heat homes, far above traditional solutions such as gas, diesel or aerothermal energy.
Main applications of geothermal energy in the home
Domestic use of geothermal energy It is not limited to heating alone. These are the most common applications in homes:
- Heating: Take advantage of the heat from the subsoil to heat the home in winter, ensuring a comfortable environment and constant throughout the day.
- Refrigeration: In summer, the system can reverse the cycle by moving heat from inside the home to the cooler subsoil, functioning as an air conditioner with a minimum expense.
- Sanitary hot water (ACS): Uses energy extracted from the ground to heat domestic water in a sustainable and economical.
- Pool heating: It is possible to keep the pool at a comfortable temperature for more months of the year, using the same geothermal system.
- Passive cold: In many areas, the system allows cool the house without significant electricity consumption, simply taking advantage of the temperature difference between the subsoil and the environment.
Types of geothermal installations and home requirements
There are several ways to capture heat from the subsoil for residential use:
- horizontal catchment: Collectors are installed at a shallow depth but occupying a large area of land. It is more economical, although it requires a lot of outdoor space, making it ideal for single-family homes with gardens.
- Vertical capture: It consists of making one or several deep wells (between 30 and 150 meters) under the house or plot. It is the most used option when the available land is limited., although the drilling cost is higher.
- Groundwater collection: Only viable if there is a constant flow of groundwater, taking advantage of the heat of the groundwater flow itself.
To install a geothermal system at home, it is essential to have enough space For collection (horizontal or vertical), a well-insulated home and, preferably, heat/cold emission systems. low temperature, such as underfloor heating or fan coils.
Advantages of geothermal energy for the home
The advantages of geothermal energy These are numerous and make it one of the most competitive energy systems today. Some of the most relevant are:
Long-term financial savings
The energy consumption of geothermal heat pumps can be up to 70-80% lower to that of conventional heating and cooling systems. This translates into a lower bill to heat the home and heat water, especially in large houses or in cold climates.
La amortization of the initial investment, which depends on multiple factors such as the climate zone, use, and size of the home, is usually between 5 and 10 years, and even less if public aid and tax breaks are used. You can learn more about the differences between renewable energies in aerothermal energy versus geothermal energy.
Low maintenance cost
Since they do not use fuels or require combustion elements or external units, The maintenance of a geothermal installation is minimalThey are robust systems with few moving parts and easy maintenance, which reduces their annual cost compared to traditional boilers or air conditioners.
Long system life
Geothermal HVAC systems can last 15 and 50 years between, depending on their components. Heat pumps are typically guaranteed for up to 10 years, and underground collectors require little or no maintenance, ensuring a long-term and reliable investment for decades.
Heat and cold with the same equipment
A single geothermal installation allows generate heating in winter and cooling in summer. In addition, it can heat the pool and produce hot water simultaneously, simplifying the home system and eliminating redundancies.
Free passive cooling
In areas where the subsoil temperature is below 15 ºC, it is possible to obtain cooling in summer. without additional electricity consumption, only taking advantage of the thermal difference between the ground and the environment, which results in significant savings.
It does not alter the aesthetics or generate noise
Being a buried system, does not require visible units such as solar panels or outdoor unitsThis maintains the home's aesthetics and prevents acoustic disturbances, as all the equipment is hidden.
Renewable, perpetual and inexhaustible energy source
Geothermal energy is clean, sustainable and available all year round. It does not depend on the climate and, if the installation is well sized, you surely won't run out of energy to air-condition your home.
Reduction of emissions and pollution
Its operation does not generate polluting gases, eliminates the risk of combustion and CO2 emissions can be practically zero if kept in a closed circuit, helping to reduce carbon footprint and mitigate climate change.
Public incentives and bonuses
Institutions offer aid, subsidies and tax benefits to encourage their installation. Some cover up to 50% of the cost and offer tax breaks such as property tax (IBI) or benefits for personal income tax (IRPF). reduced return time of the investment. Consult the possibilities in your community at Castilla la Mancha.
Possibility of integration with photovoltaic energy
The electrical consumption of the pump can be covered with photovoltaic installations, achieving greater energy self-sufficiency. The regulations also allow for the distribution of surplus energy into the electricity grid and the receipt of financial compensation. Costa Rica produces almost 100% of its energy from renewable sources..
It does not present health risks like legionella
By eliminating condensation tower systems, the risk of legionellosis is reduced and other health problems associated with traditional air conditioning systems, offering greater safety for families.
Disadvantages and limitations of domestic geothermal energy
Despite its many benefits, There are drawbacks that are important to keep in mind before deciding on this technology:
High initial cost
The investment required for installation is usually considerably larger than a conventional gas or electric system. The drilling and advanced pump technology represent a significant expense, although this is offset by future savings and available assistance.
Dependence on land and available space
Especially in urban environments or homes without a garden, It can be difficult to install horizontal intakesThe vertical option requires deep drilling, which can be expensive and complicated in certain terrains.
Complex process and prolonged works
Its implementation It is neither quick nor easyIt requires studies, permits, drilling, and specialized execution, making lead times longer than traditional systems.
Dependence on low temperature systems
To achieve maximum efficiency, it's recommended to use low-temperature radiators such as underfloor heating or fan coils. If the home has conventional radiators, it may be necessary to upgrade them to take advantage of geothermal technology.
Geographic variations and associated costs
Geothermal potential varies by region and terrain. In some cases, drilling costs or a lack of suitable resources can make these systems unviable or prohibitively expensive.
Minimal but present environmental risks
Drilling can release small amounts of gas or affect groundwater if not done properly. It can also cause thermal pollution or subsidence in large-scale installations, although these risks are minimal for domestic use.
Sustainability if not managed properly
Reserve depletion can occur if fluids are not properly replenished. Proper management and the involvement of specialized companies are essential to prevent environmental damage.
Limitation on on-site energy
Geothermal energy cannot be transported over long distances, so its use is limited to the local level, at the drilling or collection site.
Prospects and future trends in domestic geothermal energy
The growth of technology and greater environmental awareness are favoring the development of geothermal energy in homes and buildings. Countries like France, Germany, and Austria have been using it for decades, and in Spain it still represents a small percentage of renewable energy, but the potential for expansion is considerable.
Improvements in deep drilling and access to warmer resources will reduce visual impact, optimize resources, and exploit previously impossible deposits. Public aid and lower costs due to economies of scale will facilitate access to more users.
Incorporating a geothermal system into your home is a reliable, responsible, and sustainable decision for those with the land and the necessary investment. Integration with other renewable energy sources, such as photovoltaics, promotes self-sufficiency and reduces dependence on large utilities and the energy market.
Choosing geothermal energy involves prioritize well-being, savings, and sustainability For your family and the planet. Maintaining a suitable temperature year-round, at a very low cost and with a minimal ecological footprint, is more accessible than ever if you educate yourself and seek professional advice before taking the plunge.
