Italy - Electricity Generation

Installed geothermal generating capacity (December 2009) in MW 

Larderello594.5
Travale / Radicondoli160
Mt. Amiata88
Total842.5

There are two major geothermal areas in Italy: Larderello- Travale/Radicondoli and Mount Amiata. In the year 2008, with the installed capacity of 810.5 MW (711 MW efficient capacity) the gross electricity generation reached 5.5 TWh and in 2009 two additional units were commissioned, increasing the capacity up to 843 MW. All the Italian fields are operated by Enel Green Power. The geothermal production is only 1.8% of total national electricity, but it is a relevant regional quota of 25% for the entire Tuscany.

Larderello and Travale/Radicondoli are two nearby parts of the same deep field, covering a huge area of approximately 400 km2, producing super-heated steam at pressure of 2 MPa and temperature in the range 150-270°C. In the Larderello side the exploited area is 250 km2, with 22 units for 594 MW installed capacity; in the Southeast side of Travale/Radicondoli, covering a surface of 50 km2, there are 160 MW (6 units) of installed capacity. The condensed water from Travale is reinjected into the core of the Larderello field through a 20 km long water pipeline. Four additional units were thus installed in the period 2005-2009 with a total capacity of 100 MW, of which 52 MW represent a net capacity increase, while 48 MW replaced old units, decommissioned because obsolete: Nuova Lagoni Rossi (20 MW), Nuova Larderello (20 MW), Nuova San Martino (40 MW) and Sasso 2 (20 MW)

The very long exploitation of Larderello and Travale/Radicondoli fields is an excellent example of a sustainable production from a geothermal system. After the stabilization of production in the period 1970- 1980, the exploitation of the deep reservoirs (with pressure of 6-7 MPa and temperature of 300-350°C, at depth of 3,000-4,000 m) and the massive positive effect of the reinjection into the field have given an impressive contribution to the increasing of the steam extraction. The much more evident increase in electricity production is a consequence of the introduction of the new generation power plant after year 2000, with an overall better efficiency.

Mount Amiata area includes two water dominated geothermal fields: Piancastagnaio and Bagnore. Their exploitation started in 1960. In both the fields a deep water dominated resource has been discovered under the shallow one, with pressure of 20 MPa and temperature around 300°C. Serious acceptability problems with local communities are slowing down the project for the full exploitation of this high potential deep reservoir. Presently, there are 5 units with 88 MW of installed capacity: one in Bagnore and four in Piancastagnaio.

New Projects

Projects for further 112 MW are approved and will be realized in the coming years: four new plants in Larderello/Travale, one in Bagnore and investmement in the field development in Piancastagnaio, with a net increase of 80 MW, considering the decommissioning.

For the "zero-emission in geothermal program", an important investment plan has been launched, in order to mitigate the H2S and Hg effluent to the environment with a specific treatment, using a technology fully designed and developed by Enel: AMIS plant (Baldacci et al., 2005), reaching a very high efficiency in H2S and Hg removal, lower capital and O&M costs in comparison with commercial process, no solid sulphur by-products (liquid streams reinjected in the reservoir) and unattended operation (remote control). Approximately 80% of the effluents are currently treated by AMIS systems. 

Taken from Ruggero Bertani’s paper, " Geothermal Power Generation in the World 2005–2010 Update Report ", published in Proceedings of the World Geothermal Congress 2010, Bali, Indonesia, 25-29 April 2010.