Geothermal energy in Italy: where and how it is produced

Italy has potential resources of extractable and exploitable geothermal energy estimated at between 500 million and 10 billion tonnes of oil equivalent. This means between 5,800 and 116,000 terawatt hours of energy, compared with annual energy requirements of just over 300 terawatt hours. In short, it would only be necessary to extract a small fraction of that energy to fully satisfy all domestic demand, especially since this data only concerns the surface layer, less than five kilometers in depth. Renewable, clean and inexhaustible, the energy released in the form of terrestrial heat still plays a relatively marginal role in the Italian energy mix, contributing just a few percentage points. In spite of this, Italy is one of the main producers of geothermal energy in Europe and the world. The driving force behind this is the country’s natural wealth of geothermal resources; there are numerous natural hot springs in various areas of the peninsula that are ready to be exploited as a key feature of the national energy transition towards green energy sources. The long history (in short) of Italian geothermal energy The advent of geothermal energy in Italy dates back to the beginning of the 1900s. In reality, however, in the area of present-day Tuscany, historical sources have revealed that people have been exploiting the heat from its natural springs since antiquity: Etruscan populations did so for at least the entire first millennium BC. In fact, it was in Tuscany, at Larderello in the province of Pisa, that the world’s first geothermal power plant was built. Since those pioneering technical experiments more than a century ago, the plant has played a central role in the innovation of geothermal energy, and more generally, in the ability to exploit geothermal sources. Initially, the steam released naturally from the ground was used as an alternative to coal-fired steam engines; later this activity became increasingly oriented to transforming heat into transportable electric energy. Alongside this transformation, the structure of the plant has also undergone substantial changes. In the past, the heart of the plant was the so-called lagone, the direct source of hot water mixed with steam at temperatures of up to 150°C. Today, however, injection and extraction wells are drilled into the ground to depths of more than 4 km, where geothermal fluid is captured. The heat is directly exploited in the form of steam, powering turbines that generate electric energy. In recent years the amount of geothermal energy produced and the installed capacity have been growing steadily, but at a rather slow pace. In the decade between 2007 and 2017, for example, the overall increase in installed capacity amounted to just 10%. All of which shows that geothermal energy has never become a leading form of renewable energy in Italy, despite its huge potential. Where are the geothermal plants in Italy? As mentioned above, the region that represents Italian geothermal more than any other is Tuscany, for reasons that are both historical and geological. Beginning with Larderello – which today is home to Europe’s largest geothermal plant – the number of regional geothermal plants has multiplied over the decades, and there are now more than thirty. Most of Tuscany’s geothermal energy comes from the heat derived from the intrusion of a magmatic pluton beneath the volcanic system of Mount Amiata. More generally speaking, the main provinces where electric energy is produced through the exploitation of geothermal resources are Pisa, Siena and Grosseto. In Italy there are many other areas with abundant geothermal resources, such as the Veneto region, especially in the area of the Euganei hills near Padua, and the Friuli-Venezia Giulia region in the area near the town of Grado, where holes have been drilled to provide direct heating for buildings. Then there is also Campania, especially in the area around Naples between Campi Flegrei and the island of Ischia; in Sicily in Alcamo, Sciacca, the Aeolian Islands and Pantelleria; and finally, Emilia Romagna, in particular Casaglia in the province of Ferrara, where there is a complex system of aquifers known as the Ferrara Ridge. All of these regions, however, when compared with Tuscany, have an almost negligible impact on the Italian energy balance in absolute terms, even though, at least on the map, Sicily and Campania (including some marine areas) have potential that is comparable with Tuscany. There are also other opportunities in Basilicata, Veneto and Sardinia (with enhanced geothermal systems, EGS), as well as in Emilia Romagna, Puglia and Abruzzo for geopressurized systems. How much geothermal energy is produced in Italy? More or less, about 6 terawatt hours of energy is generated each year in Italy, with an installed capacity in the order of 1.1 gigawatts (or 1,100 megawatts). Of this, just over 900 megawatts correspond to the capacity of the plants that convert heat into electric energy, so-called geothermoelectric plants, while just under 200 megawatts derive from the direct use for urban heating, thermal springs, therapeutic uses and cultivation in greenhouses. The fact that, in Italy, around one seventh is used for thermal use and six sevenths for electric use is now well established, as has been documented by the Italian Geothermal Union. To be more precise, in terms of total energy, the estimates for 2018 range between 5.71 and 5.76 terawatt hours, while for 2019 the variation is much closer at between 5.687 and 5.689, at least according to national analysis. European studies for 2019 report a value that is 7% higher, at 6,086 terawatt hours. Given that we are speaking of a number of relatively small plants, the fluctuation between one year and another may also be due to the variation in available energy beneath the ground or to specific interventions. For example, the small reduction in 2019 compared with the previous year can be traced to the shutdown at the main plant in Larderello in the month of December in order to carry out maintenance work. Compared to national energy needs, geothermal makes up just under 2%, or around 5% of renewables alone (data for 2019). Statistical data about the European and global scenario The three major players in the geothermal sector in Europe (broadly speaking) are Italy, Iceland and Turkey. With a total of 1,086 megawatts of installed capacity according to the EGEC geothermal market report 2020, Italy stands out from the other countries in central and northern Europe. For instance, France does not even reach 700 megawatts, Germany just 400, Spain is basically at zero (3 megawatts to be precise) and Portugal has 33. Despite the fact that Iceland, which is at a substantial advantage due to its natural resources, has an enormous installed capacity of more than 2,900 megawatts, in terms of actual energy produced, its levels are comparable with Italy’s: Iceland too produces an average of 6 terawatt hours a year. Out in front, however, is Turkey, both in terms of installed capacity (2,500 megawatts) and energy produced (7.7 terawatt hours) but in this case it is also worth considering the country’s greater size. France, which is the highest ranking among central European countries, produces just 216 gigawatt hours each year. Finally, taking a brief look outside Europe, we can see that in terms of installed capacity, but also energy generated, Italy is clearly one of the world’s top ten countries. Way out in front, at least for now, are the United States and the Philippines, while also ahead of Italy by just a few percentage points are Indonesia and Mexico. Interesting facts about geothermal energy Among the features of Italian excellence in this field is a much higher than average respect for the development goals set for geothermoelectric. By the end of 2019, Italy had already comfortably surpassed the target of 80% to be achieved by the end of 2020, while aside from Portugal (just under 40%) all other European countries have not even achieved 20% of their targets. Less well developed, however, is the direct use of underground heat, which, as has already been mentioned, remains a minor activity in Italy. The percentage of development at the end of 2019 reached 43% of the 2020 target, and in absolute terms the energy collected was greater than that in Germany, France and Hungary. Among the characteristics that make geothermal a particularly advantageous renewable source at the national level are the related advantages in terms of employment. In fact, the number of so-called green jobs generated by the sector far exceeds the energy capacity generated. According to an Italian study conducted by the Energy Services Manager (GSE), each megawatt of installed and maintained geothermal capacity creates 34 jobs, compared with 19 for wind power and 12 for photovoltaic. With around 900 megawatts installed, there are two thousand people employed in stable work (to which should be added those in temporary positions), so if the goal of doubling installed capacity were to be achieved, this would result in a total of 4,000 full-time jobs and a total of 30,000 jobs spread over the various years. Trends, innovations and observations One of the most alluring prospects for geothermal energy, which is also shared with other renewable sources, is its growing yield. While until a few decades ago the upper limit was just a few percentage points, today geothermal plants can reach over 20% (heat pumps cab even reach 50%) and are capable of extracting more than four times more energy than is required to keep them running. Among the most interesting technological advances today is the possibility or preventing toxic or climate-altering gases being released from underground, thereby preventing them from being emitted into the atmosphere. On this front, data from the Italian Geothermal Union shows that carbon dioxide emissions that have been avoided thanks to geothermal have passed from 3.7 million metric tonnes in 2010 to 4.0 million in 2015. This leap forward cannot be explained solely by the increase in installed capacity, but also by technical improvements at the plants. Furthermore, it is possible to create inverse geothermal, or low enthalpy geothermal, which works also with temperatures lower than 100°C and exploits the subsoil as if it were a storage tank for excess heat during the summer, which is then recovered during the colder months in the form of electric energy. Looking to the future, it is believed that through the 2020s the production of geothermal energy in Italy will be limited to the exploitation of resources with a temperature of at least 90°C, while in the 2030s new technologies will also make it possible to benefit from sources at lower temperatures, with so-called non-conventional geothermal. The forecasts indicate that it is possible to achieve an installed capacity of between 1,070 and 1,140 megawatts by 2030 for geothermoelectric alone, a figure which is set to increase dramatically in the following twenty years to reach between 2,000 and 2,500 megawatts installed by mid-century. In parallel, the energy generated could be close to 7 terawatt hours annually (between 6.7 and 7.3 to be precise) by 2030, reaching between 13 and 16 terawatt hours by 2050. This means that in the coming thirty years, there will be a doubling or even tripling of the existing quantity, helping geothermal to cater for a share of 3-5% of Italian energy needs. The next few decades could be the ones in which geothermal really expands beyond Tuscany, with the rosiest forecasts predicting that total production from other regions could make up 5-6% of national production by 2030 and 30-40% by 2050.

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Geothermal energy in Italy: where and how it is produced

Geothermal energy in Italy: where and how it is produced