The Cloud Factory

The toponym “Valle del diavolo” encompasses several municipalities and hamlets of the area of the Val di Cecina in Tuscany, located between the provinces of Grosseto, Pisa and Siena. The origin of the name derives from the presence of numerous spontaneous geothermal manifestations that flow from cracks in the soil (fumaroles, geysers, bulicam) still visible today. Ancient popular culture attributed to this place the dwelling of the devil, who snorted from the land to manifest his presence.
The valley is marked by natural and artificial cracks from which puffs of steam and fluids come out, which emissions can reach temperatures between 130-160°C and by the “Biancane”, sulphurous areas of different sizes in which white sulphurous rocks emerge, which contrast with the green of the surrounding woods. Since the early nineteenth century this geographical area became the privileged place of research for the exploitation of geothermal energy. The cultivation of this renewable underground resource has made it possible to transform a harsh area of Tuscany with a lunar landscape into an area where today the progress of clean energy has reached world records.

View of the Valle del Diavolo, near Monterotondo Marittimo (GR). In the center, the plumes of smoke from the "Lagone", the only remaining example of the exploitation of boric acid begun in Monterotondo Marittimo in 1812, today transformed into an extraction and injection well of the "Monterotondo Marittimo 1" geothermal power plant.

Steam and fluids escape from the fractures of the rocks of the "Biancane" geosite near Monterotondo Marittimo (GR). The fluid has a temperature of about 110°C and is made up of 95% water vapor and the remainder of carbon dioxide, methane, ammonia and hydrogen sulphide. Chemically aggressive vapors react with the rocks they pass through, leaching them and altering the minerals.

The researchers from the National Institute of Geophysics and Volcanology (INGV) analyze the composition of the gas at the "Biancane" geosite, Monterodonto Marittimo (GR), Italy.

Rosario Avino, geochemist, measures the gases emitted by the soil with a “Minigas”, a device designed to recognize the concentrations of carbon dioxide, sulfur dioxide and hydrogen sulphide at the "Biancane" geosite, Monterotondo Marittino (GR), Italy.

The superficial manifestation of the Biancane’s geodiversity creates a landscape resembling Dante’s Inferno. The color of the soil is unusual, with areas of pure white mixed with bright ochre-colour rocks created by geothermal alteration of the rocks. The ground and the rocks are hot, the vapor emerges puffing from the earth and the emanations of citric acid constantly stimulate the sense of smell.
The origin of the exceptional landscape of the Biancane geosite are to be found in the unique characteristics of its underground.
The normal temperature gradient observed in the earth’s crust is 3 degrees centigrade increase per 100 meters of depth. This area, on the other hand, is characterized by a high geothermal anomaly due to the presence of a slow-cooling granulated pluton at a depth of 4000 meters. While magma is usually found at 20-70 km below the surface, in this area magma can be found only 7km below the surface.

The "San Federigo" boraciferous shower heads at Lago Boracifero, Monterotondo Marittino (GR), Italy. In this place, starting from 1827, the first industrial plants for the production of boric acid were built.

Inside the natural draft cooling tower of the "Monterotondo 1" geothermal power plant near Monterodonto Marittimo (GR), Italy. The cooling tower cools the water necessary for the condensation of the endogenous vapor.

Gloria during her shift in the turbine area of the "Monterotondo 1" geothermal power plant near Monterodonto Marittimo (GR), Italy.

Enrica Marotta, INGV volcanologist, pilots a drone for thermal detection at the "Biancane" geosite near Monterotondo Marittimo (GR), Italy.

An INGV drone maps an area to obtain the distribution of thermal anomalies on the ground at the "Biancane" geosite near Monterotondo Marittimo (GR), Italy.

Aereal view of the "Biancane" geosite near Monterotondo Marittimo (GR), Italy.

Geothermal event at the "Putizze" geosite near Sasso Pisano (PI). The "bulicam" is a small depressions in the ground in which geothermal waters and mud are collected in continuous bubbling due to the endogenous gases emitted by the source that feeds them.

Since the end of the eighteenth century, the puffs of steam from the Devil’s Valley have attracted scientists of different backgrounds, scholars and researchers eager to reveal the secrets hidden under the rocky and steaming crust on which their feet rested.
The geothermal manifestations of the Biancane are regularly studied by teams of volcanologists who monitor its evolution and exploit the specific conformation of the geosite to test new measurement methods and research methodologies.
Estimating the surface temperature, the heat flow as well as analyzing the gases emitted over time with periodic measurement campaigns is decisive for controlling the area, because any change in these parameters can indicate an alteration of the entire underground geothermal system and trigger changes on the surface of the earth’s crust and in the economies of the various human realities that, over the centuries, have benefited from it.

The grafting of a steam pipeline in the municipality of Castel Nuovo di Val Cecina (PI). The territory of the geothermal district is characterized by the intertwining of steam pipes that harness the steam released by the shower heads and convey it to the geothermal power plants.

View of Sasso Pisano, Castelnuovo di Val Cecina (PI). Through district heating, the heat to warms the rooms and sanitary water reach the residents' homes directly. The geothermal exploitation of the district provides useful heat to heat about 10 thousand families.

A steam pipeline on the SP329 on the outskirts of Monteverdi Marittimo (PI). Throughout the geothermal district there are about 480 km of steam lines.

The heat exchanger of the "Valle Secolo" geothermal power plant in Larderello (SI). The steam extracted from the depths of the geosite is saturated with corrosive substances which limit its direct use even if subjected to purification treatments. In systems called heat exchangers, the high temperature of the steam is used to heat running water and obtain clean high-pressure steam.

The turbine room of the "Valle Secolo" geothermal power plant in Larderello (SI). The geothermal power plant is the largest in Europe and has an installed capacity of 120 MW.

The world history of the exploitation of geothermal resources boasts a record in this area. In 1911 the first geothermal power plant in the world was built in Larderello. From that year on in the Devil’s Valley, the heat became an industry and the horizon was filled with cloud factories that used the steam from the earth to generate electricity.
Today the Tuscan geothermal district is the oldest and at the same time the most innovative on the planet. It extends over a cultivation area of about 576 square kilometers with an annual production of about 6 billion kWh produced by 34 geothermal power plants located between the provinces of Pisa, Siena and Grosseto. Furthermore, according to the current analysis parameters, the energy exploitation of the valley avoids the consumption of 1.1 MTep and the emission into the atmosphere of 3 Mt of CO2eq, which is combined with a production of heat equal to about 454 GWh, capable of avoid the emission of 121 thousand tons of CO2eq.
The electricity produced in the district and its surroundings satisfies 30% of regional needs and represents 70% of regional production from renewable sources. In the circular economy of this area, geothermal energy satisfies the consumption of over 2 million families and provides useful heat to warm about 10 thousand users in 9 municipalities, as well as 30 hectares of greenhouses, dairies and to feed an important agricultural and gastronomic chain.