The Chiusdino power plant: a sustainable model from the heart of the Earth

The exploitation of geothermal energy as a source of heat for thermal baths, the production of chemicals and later electricity generation, began in Italy, in Tuscany to be precise, in the area between Pomarance, Castelnuovo Val di Cecina and Chiusdino. The most emblematic site is the so-called “Valle del Diavolo” (The Devil’s Valley). While every location has its own story, this valley flaunts thousands of years of history, and is writing a new page every day thanks to Enel Green Power’s commitment to sustainability across the planet, and more specifically in this valley and in geothermal areas, as a guiding principle for the management and cultivation of natural resources. In Tuscany, EGP manages the world’s oldest and most innovative geothermal complex, with 34 geothermal electric plants spread across the provinces of Pisa, Siena and Grosseto, which have all adopted the sustainable plant model. The over 6 billion KWh produced across the regional territory satisfy more than 30% of the region’s energy needs, and also supply heating to more than 10,000 residential users, around 30 hectares of greenhouses, and numerous companies in the fields of food and agriculture, floriculture, crafts and leatherwork. A model of sustainable efficiency The Chiusdino plant, which was built in 2011, has a 20-MW turbo generator set capable of generating up to 150 million kWh of energy per year, saving 31,000 metric tons of oil equivalent (toe). The turbine is powered by approximately 130 T/h of geothermal steam originating from four nearby wells. The plant, like the other 33 in the Tuscan geothermal area, is equipped with a system to separate and clean steam and eliminate water, and with a mercury and hydrogen sulfide emissions abatement system (with Enel’s proprietary AMIS technology), which eliminates incondensable gasses from the process. The design of the plant took into account the world’s highest quality standards and the most innovative environmental technologies. During the plant’s regular operations and maintenance, all relevant safety and environmental standards are applied, as well as those to ensure respect for the local communities, in full compliance with the “sustainable plant” model: reusing materials, recycling waste, recovering and recirculating oils, monitoring the storage of lubrication oils and using equipment to wash mechanical parts naturally and degrease them with organic methods. Furthermore, the plant has introduced digital checklists for each phase of its operations, solutions to limit energy consumption for lighting, and non-invasive barriers to protect local wildlife. The plant, moreover, is equipped with a sophisticated monitoring and remote diagnostic system, capable of ensuring the highest standards of reliability and efficiency. Thanks to district heating, the town is carbon free In 2019, the district heating system for the town of Chiusdino was completed using geothermal steam as a primary heating source for homes, shops and craft workshops. With the second phase of the project, the town of Chiusdino has become completely carbon free, eliminating all emissions of CO2 and fine particulate matter from boilers and stoves powered by fossil fuels. It is estimated that this will lead to 2,600 metric tons fewer CO2 emissions a year, and avoid the importation of 1,000 TOE, with remarkable benefits in environmental terms. This is also an important example of circular economy, because thermal resources are a form of residual energy from the process that generates geothermal electricity. District heating plants enable the reuse of residual heat for the benefit of the town’s population, allowing people to save on their heating costs, while also serving as an incubator for the creation of new businesses that can benefit from the low cost of heat. Moreover, geothermal district heating boosts the value of local real estate, making houses healthier to live in and encouraging the use of properties that may have been abandoned otherwise. This system of district heating is present in 10 municipalities that are home to geothermal plants, and provides heating to more than 10,000 residential users, contributing to a remarkable reduction in greenhouse gas emissions. Protecting the environment for sustainable tourism The municipality of Chiusdino is rich in resources, first and foremost its environmental, architectural and cultural heritage. The landscape was carefully conserved by former generations, and is now appreciated every year by thousands of tourists who visit the production sites and nature reserves, and enjoy the local cuisine and tranquility. The Chiusdino plant meets extremely high environmental standards: thanks to the multiple uses of its geothermal resources, it can be considered a model facility and is often used for educational events with schools, universities and companies. Enel Green Power’s geothermal power in Tuscany offers tourists, associations, schools and organized visitor tours important cultural and naturalistic itineraries, including the Museum of Geothermal Energy and the demonstration fumarole in Larderello, the Biancane Park in Monterotondo Marittimo, home to the brand new Mu.Bia Museum, geothermal trekking along the “Geotermia & Vapore” (Geothermal energy & Steam) footpath from Sasso Pisano to Monterotondo Marittimo, the natural wonders of the Park of the Fumaroles and the San Federigo area, in addition to the Etruscan-Roman baths in Sasso Pisano. The local territory can also count on important partners like the Consorzio Sviluppo Aree Geotermiche (Co.Svi.G.) and the Comunità del Cibo a Energie Rinnovabili, both crucial to promote the development of an agricultural production chain and food and wine culture that prioritizes sustainability. In fact, local basil, tomatoes and flowers are cultivated in geothermal greenhouses. There are also food and wine itineraries that invite tourists to visit producers of cheeses, cured meats and beer, all made using geothermal heat. In Italy’s geothermal area, EGP is thus showing the way forward with one of the best examples of “sustainable plant”, sharing resources and enabling thousands of families to meet their energy needs without having to use fossil resources, while also making an important contribution to protecting the planet and boosting global sustainability.

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The Chiusdino power plant: a sustainable model from the heart of the Earth

The Chiusdino power plant: a sustainable model from the heart of the Earth

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