The geothermal resources of Vulcano Island (Aeolian archipelago, Italy)

We evaluated the geothermal resources of Vulcano Island considering the available geological, geochemical, and geophysical information in the framework of the conceptual model of La Fossa magmatic-geothermal system. Having ascertained that the shallow groundwaters of the Vulcano Porto plain are heated by geothermal steam and gases and are not directly impacted by magmatic fluids, we have adopted the P_CO2 and temperature distribution in these shallow groundwaters to delimit the areal extension of the underlying geothermal aquifer, which is 0.777 km² and 0.752 km² based on the P_CO2 and temperature maps respectively, in agreement with the area from MT data, 0.7 km2. The revised volume method was used considering the specific productivity of liquid-dominated geothermal systems, 40 t⋅h^-1⋅km^-3, and assuming that the geothermal aquifer has a thickness of 2.8 km and a temperature of 200–275 °C. The hourly production rate of geothermal fluids resulted to be in the range 84.2–87.0 t⋅h^-1, while the extractable thermal and electrical powers turned out to be 25 ± 6(1σ) MWt and 8.3 ± 2.0 MWe, respectively. Drilling of one or two production wells and one reinjection well (depth in the order of 1.5–2.0 km) could be therefore a suitable technical solution.