The role of renewable sources in the Ecological Transition process: focus on hydroelectric energy

Filippo Verre - April 20, 2022

* L’immagine di copertina di questo report è stata presa dal sito Student Energy, consultabile al seguente link: https://studentenergy.org/source/hydro-power/

Physicist and academic Roberto Cingolani was (and still is) the first Minister of Ecological Transition (MiTE). Founded in February 2021, this ministry replaced the Ministry of the Environment and Protection of Land and Sea (MATTM). The main reason for the creation of this new institutional entity, focused precisely on the concept of "ecological transition", lies in the new approach inaugurated by Italy from an environmental point of view. An approach based on the protection of the environment and the protection of the national territory, but also aimed at the production of clean and sustainable energy in compliance with the international obligations that our country has undertaken in the fight against climate change. In this perspective, there are many documents presented in recent years by authoritative scholars and research institutions, both Italian and international, which underline a change of direction with the utmost urgency regarding the adoption of eco-sustainable production policies. The objectives of the new eco-friendly course of Italian politics are summarized by the expression Green New Deal, a plan of economic and social reforms aimed at safeguarding our ecosystems through the gradual overcoming of fossil fuels as primary sources. Among the various goals set by the authorities, there are also interventions aimed at promoting measures to decarbonize the economy, to reduce the use of plastic or replace it with alternative materials, to encourage sustainable tourism and to adapt/mitigate the risks on the territory deriving from climate change.

The attention that Rome dedicates to this matter is maximum, also in relation to the well-known war story involving Russia and Ukraine. The second point of the National Recovery and Resilience Plan (PNRR), entitled "green revolution and ecological transition", provides for large investments in this direction [1]. In this respect, in addition to the reduction of fossil fuels, a greater use of renewable sources for the production of electricity plays a primary role. At a European level, it is important to underline that Italy is a "virtuous" state in terms of the exploitation of renewable sources. Almost a third of the electricity produced in our country comes from green sources: the hydroelectric sector, which is predominant, is followed by solar-photovoltaic, bioenergy, wind and geothermal. Overall, Italy is the third largest producer of energy from renewable sources in Europe. Alternatives to fossil fuels, in fact, represent a significant portion of the energy production of the Bel Paese, with a percentage that is constantly growing year after year[2]. In fact, among the large European nations, Rome holds the highest share of electricity generated through the exploitation of non-fossil sources. As can be seen from Fig. 1, in fact, at the end of 2018 – in a pre-war and pre-pandemic scenario, therefore – Italy preceded many large continental countries and almost reached 20% (of the total) of energy generated through renewable sources.

Fig. 1: Quota di energia prodotta da fonti rinnovabili in Europa Paese per Paese
https://marketingdelterritorio.info/index.php/it/opinioni/3648-energie-rinnovabili-l-italia-e-l-europa-possono-puntare-piu-in-alto

Renewable energy sources in Italy. An overview

Following the referendum held in November 1987, Italy renounced nuclear energy. The Three Mile Island accident[3] in 1979 and, even more, the Chernobyl disaster in 1986 played a decisive role in the collective imagination of the time. 80% of voters expressed themselves in favor of the requests put forward by the promoters of the popular consultation, which were focused on the abolition of nuclear energy on the national territory[4]. In fact, therefore, Rome has not produced nuclear energy since the end of the 1980s. However, it is worth noting that nuclear energy is still used on a massive scale, given that even today approximately 10% of our electricity needs are satisfied by importing energy produced by French nuclear power plants. It is a real paradox; according to Ferruccio De Bortoli, editorialist and former director of Corriere della Sera: “Countries like ours no longer want to hear about nuclear power but are in the position of hoping that others – the French and the English for example – do not imitate them. Otherwise there would be trouble, serious trouble”[5]. The reason for this is that highly industrialized countries like Italy need large quantities of energy both to satisfy the national production machine and to guarantee electricity for domestic use. Given the gradual suppression of fossil fuels planned for the next few years and with the lack of nuclear energy produced within our borders, Rome is in fact obliged to supply itself with a source considered dangerous and extremely polluting. However, even today nuclear energy is indispensable to guarantee high rates of electricity production with not so high environmental costs[6]. In this regard, a few weeks ago the European Commission introduced natural gas and nuclear power in the list of renewable sources. The Commission defines them as “energy sources useful for the ecological transition of the Union, and can have – under certain conditions – the EU label for green investments”.

Fig. 2: Immagine di un atomo “incandescente”
https://gametimers.it/fusione-nucleare-in-corea-del-sud-e-stata-riprodotta-una-stella-artificiale-in-miniatura-per-pochi-secondi/

To understand the choice of the European Commission, considered absurd and harshly criticized by many environmental associations, we must refer to one aspect. What is considered most dangerous in this historical phase is the very high production of CO2, responsible according to many experts for the dizzying increase in temperatures on our planet. Nuclear, from this point of view, is a very "sustainable" source since it does not produce CO2. It is also a source that can be exploited regardless of climatic conditions; once activated, a nuclear power plant works at full capacity even in conditions of lack of wind or sun, just to mention two renewable sources that in recent years have experienced a massive increase from a quantitative point of view in our country. At the same time, the exploitation of nuclear energy involves significant risks, especially with regard to first and second generation power plants. Problems related to safety and the disposal of radioactive waste remain by far the main negative aspects that still limit the spread of atomic energy today.

In addition to nuclear power, which, as mentioned above, has been classified as a renewable source and is not produced on our national territory, there are many “clean” sources that Italy uses regularly. Starting from the hydroelectric sector, which will be analyzed in detail in the next paragraph, up to including the sun, wind and heat of the earth; they represent the main sources used to generate high rates of non-polluting energy. These are truly strategic resources to draw from, given that they are abundant in our ecosystems and potentially infinite. Of course, there may be periods in which more abundant clouds limit the contribution of the sun, or cases in which there is an absence of wind for an indefinite period. However, both the sun and the wind will be part of our life on this planet, as well as the heat that is released from the earth, the so-called “geothermal”, another renewable source that has seen significant growth in recent years even if with less importance in the total basket of renewables. Not to mention other sources such as wave motion and tides, in addition to the various bio-fuels that make the share of renewables in our country very consistent.

Photovoltaic boasts higher production rates in the south, thanks to the lower latitude and greater contribution of sun. Wind energy, on the other hand, is collected mainly in the large islands, Sicily and Sardinia, to which is added in general the southern part of the Apennine ridge, starting from Puglia, Campania and Basilicata, where the wind is present more or less constantly. Finally, geothermal energy has Tuscany as its center of excellence, for historical reasons and geological characteristics.

Fig. 3: Parco eolico pugliese (ottobre 2021)
https://www.ilmattino.it/economia/moltoeconomia/idrogeno_progetto_puglia_snam_edison_alboran_saipem_fotovoltaico_produzione_energia-6240210.html

The growth that all renewables have had in recent years in terms of distribution and presence on the territory has been powerful. Suffice it to say that in 2010 only 356 Italian municipalities had electrical or thermal systems based on renewables, while today we have reached almost 100% of municipalities with at least one renewable system, i.e. a total of municipalities that, in June 2020, exceeded 7,900[7]. Specifically, there are 7,776 municipalities in which at least one photovoltaic system is installed, 7,223 with a solar thermal system, 3,616 with bioenergy systems, 1,489 in which hydroelectric energy is exploited (thanks to large structures or even mini-systems), 1,049 with wind systems and 594 in which supplies are also obtained through geothermal energy[8]. Furthermore, there are already over 3,000 municipalities in which the renewable component exceeds the electrical needs of families; of these, 41 also fully satisfy the thermal one. These results are, by all evidence, very significant and demonstrate how Italy is in fact an eco-friendly country, where attention to the production of clean energy is at its maximum both at a national and local level.

If we do not take into account the energy deriving from the exploitation of water, the sun is undoubtedly the most used source for the production of electricity. In this regard, consider that about a twelfth of the total energy produced in Italy, renewable and non-renewable, comes from photovoltaic systems. A truly significant growth, which has also matured in just a few years. Progress and technological research are among the main reasons that have favored this increase. In fact, nowadays there are different ways to exploit the sun's rays. Specifically, in addition to the classic photovoltaic panels, many solar thermal systems are widespread, which exploit the energy of the sun's rays to heat water or another fluid. It should also be noted that solar energy is also used to power individual devices and instruments: from means of transport that work thanks to photovoltaic panels to satellites and space vehicles, including everyday objects or buildings constructed in remote locations that are powered by solar rays.

Fig. 4: Pannelli solari e sistema solare termico montati sul tetto di un’abitazione
https://www.qualenergia.it/articoli/e-integrare-pompa-di-calore-fotovoltaico-e-solare-termico/

As regards the exploitation of the wind, it should be noted that, in absolute terms, wind energy in Italy is progressively growing. Although at a slower rate than other European countries and the average of the continent, the wind is increasingly being "harnessed" in order to produce clean energy. In this regard, it should be considered that in our territory there are over 5,000 wind farms. As reported by the official data of ENEL Green Power, to date, in the vast majority of cases, Italian sites are characterised by wind turbines with an installed unit power between 20 and 200 kilowatts[9]; in the future, the installation of more advanced technology turbines is expected, with greater unit power and production and, for the same site considered, with an optimisation of space and land consumption. The progress made in this sector recently is very encouraging; It is estimated that the total energy obtainable with Italian wind power could double in a decade compared to the current 20 terawatt hours per year, with a transition in terms of maximum power deliverable from 11 to 19 gigawatts[10].

Even with regard to the geothermal sector, Italy confirms itself as a cutting-edge nation. Tuscany, as previously underlined, is the region with the highest presence of geothermal plants. The first plant ever built in history is in Larderello, in the province of Pisa. Since the first technical experiments at the beginning of the twentieth century, Italy has distinguished itself in the world for its innovative capacity to exploit this type of energy deriving from geological sources. In the past, the idea was to use the steam coming out of the subsoil as an alternative to coal-fired steam engines. Today, more than a century later, in Tuscany alone there are about thirty geothermal plants. The technology has evolved a lot and currently allows the exploitation of fluids extracted directly from the subsoil. Efficiency has increased significantly: geothermal plants can now produce up to four times more energy than they need to operate.

Fig. 5: Impianto geotermico di Larderello
https://www.toscanafilmcommission.it/luoghi/centrale-geotermica/

Although in percentage terms geothermal cannot compete with other renewables - also given its lesser diffusion on the territory - Italy is still at the top of the world in this type of production. Some technological innovations have made the prospects even more interesting. First of all, toxic or climate-altering gases that can be released from the subsoil are now contained and their emission into the atmosphere is avoided. Furthermore, it is also possible to create reverse geothermal energy (called low enthalpy) in which the subsoil is used as a reservoir for excess heat present during the summer season, recovering it in the cold months and transforming it into electrical energy[11].

The hydroelectric sector. The spearhead of Italian renewable sources

As we have seen, there are various renewable sources used by Italy to produce clean energy. Among these, an honorable mention undoubtedly goes to the hydroelectric sector, which has always been held in the highest regard in the production of alternative energy to fossil fuels. Hydroelectric is the renewable energy source that boasts the longest tradition in our energy sector. A story that has its roots in the late 1800s, when Italy was at the forefront of the world in the development of hydraulic systems capable of producing green energy. Until a few decades ago, it was even believed that this single renewable source could be so abundant that it alone would guarantee Italy energy self-sufficiency. This belief was so widespread and deep-rooted that hydroelectricity was nicknamed the “white coal” of the Alps. In some ways, this “coal” had (and still has) many positive aspects: water energy is environmentally friendly, available in large quantities within national borders and obtainable at low prices. All these advantages have led our country to invest heavily and immediately in hydroelectricity, with very satisfactory results.

Fig. 6: Diga di una centrale idroelettrica in alta montagna
https://www.ohga.it/lenergia-idroelettrica-la-rinnovabile-piu-usata/

The physical conformation of our territory, with the Apennine ridge and especially with the Alpine arc, make the northern regions ideal areas for the large-scale production of electricity through the exploitation of water. The steep slopes of the land, which are crucial for having high-productivity plants, allow the maximum exploitation of water kinetic energy, the principle underlying hydraulic systems.

Until the 1920s, hydroelectric power plants represented almost all of Italy's green energy, with tiny contributions from other sources such as geothermal. The only exception, as mentioned above, was the large Tuscan power plant of Larderello, built in 1904, or wind power. However, over time, from being the undisputed protagonist of the non-fossil energy panorama, hydroelectric power has lost weight. This is not so much due to a decline in production - indeed, the trend has never been downward - but to a substantial and progressive loss of interest in this alternative means of electricity production. Throughout the first half of the twentieth century, and up to and including the 1950s, the maximum exploitation of the Italian hydroelectric potential was achieved, with the construction of several large power plants. Then, however, partly due to the lack of further advantageous sources, partly due to the reluctance to invest further public funds following the Vajont disaster, from the 1960s to the first twenty years of the new century the increases in production were modest. According to a study carried out by ENEL Green Power, in the last sixty years the variations have been less than 10% overall, and with a fluctuating trend[12]. All this, compared to the growth of other energy sources, both fossil and renewable, has meant a notable loss of relative importance of hydroelectricity in the Italian energy basket.

Recently, after a long period of stagnation, energy from the exploitation of water has attracted interest again at a national level. At the beginning of 2019 – before the outbreak of the Covid 19 pandemic – there were 4,331 Italian water-powered plants[13]. If we stop to analyze the number of power plants, we can speak of a real "golden decade": in 2009 there were just 2,249, since then there has been a substantial doubling with the crucial years being 2010 (+480 plants), 2016 (+270) and 2017 (+348). This is because the hydroelectric sector has experienced a phase of strong growth in the last 15 years, driven above all by the green incentives that the government has allocated to increase the share of energy produced from renewable sources. However, it should be emphasized that the growth in number has not corresponded to an equal increase in the power generated; this is due to the fact that the average size of the plants built has decreased. The average growth in total power has been 0.7%, which is very little. The installation of small-sized plants, the so-called mini-hydroelectric, began in the early 2000s, and has seen great development over the last few decades. The overall average production at the national level has fallen from 8.4 megawatts per plant at the beginning of the century to about half, at 4.4 in 2018.

Fig.7: Piccolo corso d’acqua idoneo alla costruzione di un “mini-impianto”
https://www.logtogreen.it/mini-idroelettrico-energia-rinnovabile-a-basso-impatto-paesaggistico/

Mini-hydroelectric power certainly does not guarantee very high energy production rates. However, it offers advantages that should not be ignored, especially in this phase of ecological transition recently inaugurated by Italy. First of all, a smaller power plant compared to a large plant requires limited investments and, therefore, ensures a quick return on the initial cost. Therefore, it is not necessary to wait several years to "amortize" the costs; in fact, in a short time, the cost-benefit ratio relating to the plant will be positive[14]. Secondly, a smaller power plant has a lower environmental and landscape impact. This guarantees a more sustainable exploitation of the environment, in line with the new eco-friendly policy of Rome. Thirdly, mini-hydroelectric power allows the use of even modest watercourses to produce energy. Streams and small rivers, of which our country is also extremely rich, can be used with very satisfactory results[15].

The distribution of plants that use the kinetic energy of water to produce energy in our country is not uniform. As mentioned, the vast majority of installed power is located along the Alps. At the end of 2018, 930 plants were registered in Piedmont, corresponding to more than a fifth of the total and 14.6% of the national figure in terms of power. Lombardy follows, with 661 plants, but it is in first place overall in terms of power, with 27.2%. And then there are the autonomous provinces of Trento and Bolzano which, with 268 and 543 plants respectively, together represent 19.3% of Italian power. The ranking then continues with Veneto (392 plants and 6.2% of the power), Valle d'Aosta (173 and 5.2%) and Friuli-Venezia Giulia (233 and 2.8%). Moving down the peninsula, on the Apennine ridge, Abruzzo stands out, with only 71 plants but 5.4% of the national power, Calabria (54 plants and 4.1%) and Umbria (45 plants and 2.8%). Finally, other not negligible contributions come from Lazio, Campania, Sardinia, Tuscany, Emilia-Romagna and Marche. Conversely, Liguria, Molise, Puglia, Basilicata and Sicily together collect 2.5% of the total installed power[16].

According to data collected by GSE[17], at the end of 2018, Italy had a total installed hydroelectric power of 18.94 gigawatts. A value that corresponds more or less to 35% of the national power from green sources. In terms of energy produced, however, at the end of 2018 the annual calculation for hydroelectric had reached 48.8 terawatt hours, equal to just over 15% of the national energy requirement and 43% of production from renewable sources. Results that were certainly good but lower than what one could actually expect. The main factors that weighed on this were the lack of public investment in this sector and the fifty years of substantial disinterest in hydroelectricity. From an employment point of view, it is estimated that in Italy the people employed in green jobs related to hydroelectricity are over 15,000. Of these workers, just over 6,000 are directly involved in the hydraulic and management part, while another 4,000 are employed on the electrical front. Finally, the remaining third is made up of indirect jobs, induced by the presence of the power plants.

Conclusion

As analyzed in this report, Italy places great emphasis on energy production through the exploitation of renewables. In numerical terms, of the over 320 terawatt hours of annual electricity needs, more than a third today comes from renewable sources, or 110 terawatt hours, equivalent to about ten million tons of oil. Significant growth has been observed especially in the photovoltaic and wind sectors. Solar energy, with a share of 20%, thanks in particular to the recent accelerations already observed, plays a significant role in the basket of renewables. Looking ahead, the sun could soon be ousted by the wind, which currently reaches 16% but shows the most solid growth trend, even at a global level. The geothermal component, currently at 5%, remains residual, while bioenergy stands at 17%.

The hydroelectric sector is still our country's preferred source of electricity production using non-fossil fuels. As mentioned, 43% of energy in the entire renewable panorama is generated through the exploitation of water resources; this is emblematic of how Rome still bases much of its green energy strategy on the use of water. To further increase the already considerable rates of hydroelectric energy, especially in light of the ecological transition process inaugurated by our country, it is desirable that this sector returns to being the object of interest and investment. It is important to underline that, in order to maximize Italian water resources, it is not necessary to build other large plants or mega-dams. The former, as mentioned, have high initial costs and are linked to the exploitation of large river or lake basins. As for dams, especially if of massive size, there is the concrete risk of unsustainable exploitation of the environment and permanent alteration of ecosystems and regions.

What could be, then, the most correct strategy for a sustainable and relatively economical increase in hydroelectric energy production? According to various studies[18], the modernization of existing plants would bring a considerable increase in energy produced at low costs and with a low environmental impact. Given that a good part of the large Italian plants are over 70 years old, today the energy actually produced inevitably shows signs of age and the lack of modernization of the structures. Redevelopment works would guarantee a renewal of the plants; even with just maintenance interventions and small replacements it is estimated that in just a few years at least 5.8 gigawatts of power and 4.4 terawatt hours of energy could be earned annually, with a saving of over 2 million tons of carbon dioxide and the creation of 2,000 additional jobs (direct and indirect) for the execution of the modernizations. This would increase the electricity produced by renewables in the total energy basket and would raise the share of hydroelectric power within the green universe by 8/10 percentage points, from the current 43% to 51-53%. In addition, let's not forget the importance of new technologies and digitalization, very valid "allies" capable of making plants more flexible and long-lasting, for example by exploiting the so-called "predictive maintenance".

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[1] Il 37,5% dell’intero budget stanziato dall’Unione Europea è rivolto al finanziamento e alla promozione di progetti ecosostenibili. Ad onor del vero, si segnala che il 37% è la soglia minima voluta dalla UE; l’Italia, dunque, stanzia poco più del minimo richiesto dai vertici europei e si posiziona al di sotto della media continentale (40%). Per maggiori dettagli: https://www.iconaclima.it/italia/politiche/pnrr-italia-sotto-la-media-ue-per-le-risorse-destinate-alla-transizione-ecologica/.

[2] https://www.enelgreenpower.com/it/learning-hub/energie-rinnovabili/italia.

[3]L’incidente di Three Mile Island fu il più grave incidente nucleare avvenuto negli Stati Uniti d’America. Venne causato dalla parziale fusione del nocciolo nella centrale nucleare sull’omonima isola, nella Contea di Dauphin, in Pennsylvania, il 28 marzo del 1979.

[4]Qualcosa di molto simile si è verificato di recente anche in Germania, quando a seguito degli incidenti di Fukushima nel 2011 ben otto Tedeschi su dieci si sono dichiarati contrati alla produzione di elettricità attraverso l’atomo.

[5]https://www.corriere.it/economia/opinioni/22_gennaio_11/caro-bollette-pregiudizi-gas-nucleare-carbone-gran-rifiuto-impossibile-per-ora-e3616826-71e0-11ec-b185-e6e7d7d180a3.shtml.

[6]Si fa riferimento, naturalmente, alle tecnologie più moderne incentrate, ad esempio, sulla tecnica della fusione nucleare. Tale metodo, a differenza della fissione, permetterebbe di generare elettricità con un minore impatto sull’ambiente vista la minor produzione di scorie radioattive difficili da smaltire. Per maggiori dettagli, si rimanda al seguente link: https://www.ilpost.it/2022/02/09/fusione-nucleare-jet/.

[7] https://www.enelgreenpower.com/it/learning-hub/energie-rinnovabili/italia.

[8] Questi dati numerico-statistici sono frutto di uno studio effettuato da Legambiente (2020), consultabile al seguente link: https://www.legambiente.it/wp-content/uploads/2020/06/rapporto-comunita-rinnovabili-2020.pdf.

[9] https://www.enelgreenpower.com/it/learning-hub/energie-rinnovabili/italia.

[10] L’energia derivante dallo sfruttamento del vento aumenterà progressivamente. A livello mondiale si stima che, da qui al 2040, la capacità di catturare l’energia eolica possa aumentare di 15 volte, portando dunque il settore eolico a diventare, nella media globale, la fonte rinnovabile numero uno a disposizione dell’umanità. Per maggiori dettagli: http://www.fotovoltaicosulweb.it/guida/il-futuro-green-del-pianeta-risiede-nel-vento.html.

[11] https://www.enelgreenpower.com/it/learning-hub/energie-rinnovabili/italia.

[12] https://www.enelgreenpower.com/it/learning-hub/energie-rinnovabili/energia-idroelettrica/italia.

[13] I dati numerici degli impianti idroelettrici sono di GSE (Gestore Servizi Energetici) e sono consultabili a questo link: https://www.gse.it/documenti_site/Documenti%20GSE/Rapporti%20statistici/GSE%20-%20Rapporto%20Statistico%20FER%202018.pdf.

[14] I tempi di ammortamento di un investimento economico nel mini-idroelettrico si aggirano intorno ai 15-20 anni per gli impianti che hanno una potenza che va dai 10 e i 100 kW, mentre, per quelli con potenza inferiore ai 10 kW, i tempi di possono scendere anche sotto i 10 anni.

[15] https://www.logtogreen.it/mini-idroelettrico-energia-rinnovabile-a-basso-impatto-paesaggistico/.

[16] Questi dati sono frutto di uno studio effettuato da ENEL Green Power, che è reperibile al seguente link: https://www.enelgreenpower.com/it/learning-hub/energie-rinnovabili/energia-idroelettrica/italia.

[17]https://www.gse.it/documenti_site/Documenti%20GSE/Rapporti%20statistici/GSE%20-%20Rapporto%20Statistico%20FER%202018.pdf.

[18] Tra i vari studi sull’argomento si segnala quello di Althesys dal titolo L’idroelettrico crea valore per l’Italia. Di seguito il link del sito: https://www.althesys.com.