Modelling of hydrogen sulfide dispersion from the geothermal power plants of Tuscany (Italy)

- Hydrogen Sulfide dispersion modelling
- Hydrogen Sulfide concentrations and health risk for communities living close to the geothermal power plants
- Reliable prediction of Hydrogen Sulfide pollution in case of unexpected events
- Processes in the atmosphere involving Hydrogen Sulfide
- Comparison between results deriving from the model and observational data (field measurements)

We applied the Eulerian code DISGAS (DISpersion of GAS) to investigate the dispersion of the hydrogen sulfide (H2S) from 32 geothermal power plants (out of 35 active) belonging to the geothermal districts of Larderello, Travale-Radicondoli and Monte Amiata, in Tuscany (Italy). An updated geographic database, for use in a GIS environment, was realized in order to process input data required by the code and to handle the outputs. The results suggest that H2S plumes emitted from geothermal power plants are mainly concentrated around the stacks of emission (H2S concentration up to 1100 μg/m3) and rapidly dilute along the dominant local wind direction. Although estimated values of air H2S concentrations are orders of magnitude higher than in unpolluted areas, they do not indicate an immediate health risk for nearby communities, under the more frequent local atmospheric conditions. Starting from the estimated values, validated by measurements in the field, we make some considerations about the environmental impact of the H2S emission in all the geothermal areas of the Tuscany region.

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