Renewable, non -intermittent and inexhaustible energy to our feet
In the debate on the energy transition, geothermia remains a feature often ignored in the face of the media visibility of solar and wind energies. However, the energy from the heat of the inside of the Earth has unique characteristics that make it particularly relevant to a decarbonized, resilient and technologically diverse energy system.
The main advantage of geothermia lies in its continuous and predictable nature: it provides heat and electricity in a stable manner, 24 hours a day, all year round, with an extremely reduced environmental footprint. This reliability is especially important in an energy system where the intermittent of variable renewable sources requires greater base capacity.
In Portugal, the use of geothermal energy is concentrated in the Azores, where centered on the islands of São Miguel and Third ensure a significant part of island electricity. On the continent, use remains limited to low and very low enthalpy applications, such as heating buildings, greenhouses or industrial circuits. This limitation is explained by both geological factors and insufficient investment in prospecting and technological development.
Despite current limitations, Portugal has significant geothermal potential, especially in the center and north of the country. The development of innovative technologies, such as geothermal systems (ENHANCED GOTHERMAL SYSTEMS – EGS), coupled with targeted polls and deepening geological knowledge, can substantially expand areas with viability for geothermal exploitation. This advance is supported by a consolidated scientific investigation in academic institutions such as Instituto Superior Technical, whose center of natural resources and environment) has been a pioneer in the study of the national geothermal potential and the development of these technologies. At the same time, the technician contributes to the formation of qualified human resources, offering programs such as the Mines and Energy Resources Engineering course and the Master in Energy Resources Engineering, which include skills in the areas of geothermal energy, reservoir prospecting and modeling, preparing professionals to work throughout the geothermia value chain.
At European level, countries such as Italy, France, Germany and Iceland already have a tradition in using this source. More recently, the Hungarian presidency of the European Union Council boosted a new political position: in December 2024, the council adopted conclusions that appeal to the creation of a European Action Plan for Geothermia. The document proposes measures such as facilitated access to financing, reconversion of fossil infrastructures for geothermal use, simplification of licensing, rehabilitation of professionals and the creation of a European geothermal alliance, with the objective of coordinating public policies, industry and investment.
Portugal can-and should-align with this new impulse. In early 2025, the Directorate-General for Energy and Geology (DGEG) presented a strategic plan for the development of surface geothermia. This is a positive sign, but the document has not yet undergone a formal public consultation, nor has it been adopted by the Government by resolution of the Council of Ministers. In order to assume as an effective public policy, this institutional cycle must be completed: to open public consultation, adjust the plan according to the contributions received and ensure its formal approval. Only then can the country benefit from European support and truly integrate geothermia into its energy transition strategy.
Geothermia will not replace the remaining renewable sources. But in a system that needs technological diversification, supply security and price stability, there is a space that can be occupied by geothermal energy. The energy is there – literally – at our feet. We cannot waste this gift of nature.
Full Professor
Associate Professor Department of Mineral and Energy Resources Engineering
Instituto Superior Technical
