Geothermal

 

The Italian expertise

Geothermal energy is available in Italy and is not subject to seasonal changes, weather or climate conditions.

The Italian geothermal industry covers the entire chain of geothermal technologies, from shallow geothermal energy, up to hydrothermal and petro-thermal deep geothermal energy for heating, cooling and power generation: heat pumps, steam plants, turbines, trills and compressors.


Geothermal power plants

The expression "geothermal energy" usually stands for the part of the terrestrial heat that could be extracted from the subsoil and exploited by men.

A geothermal power plant converts the thermal energy of a geothermal fluid - steam or water-steam mix, resulting from circulation of water within high-temperature reservoir rocks - into electricity.

Bacins exploited for electricity generation reach temperatures above 150°C and depths ranging from some hundreds to some thousands of meters. Generally, a geothermal plant consists of:

  • systems for collecting, treating and supplying geothermal fluid to the power plant;
  • system for power generation, including: steam manifold, turbine, generator, step-up transformer;
  • system for steam cycle, including: gas extraction, condensing and cooling;
  • system for reinjecting condensed water into the geothermal reservoir.

The plant may also be equipped with systems to abate some compounds contained in the non-condensable gases and to mitigate the environmental impact.

The emissions of these plants into the atmosphere depend on the characteristics of the geothermal fluid. However, their emissions per unit of generated electricity are definitely lower than those from fossil-fired plants. 

 

Number and capacity of geothermal power plants in Italy

​ ​2011 ​ ​2012 ​ ​% 2012/2011
​Capacity class (MW) ​no. ​MW ​no. MW no.​ ​MW
​C≤20 ​27 435,0​ ​27 435,0​ ​0,0 ​0,0
​20<C≤40 ​2 ​75,0 ​2 ​75,0 ​​0,0 ​​0,0
​C>40 ​4 ​262,0 ​4 ​262,0 ​​0,0 ​​0,0
​Total 33 ​772,0 ​33 ​772,0 ​​0,0 ​0,0
 

The table displays the number and the gross maximum capacity of geothermal power plants.

During the last three years, the number of the geothermal power plants hasn't changed.

Most part of the plants are those whose capacity is less or same as 20 MW (81,8%). Those plants represent the 53% of the geothermal power plants' national capacity.

The plants whose capacity is more than 40 MW form the 12% of the total and the 33,9% of capacity. The two plants among 20 and 40 MW (6,1%) represent the 9,7 % of the fact in capacity.

The geothermal source accounts for 1,6% of the capacity of the overall RES generating mix.