Sparks

Taming a monster

 By Robin Wylie

Italy is the most volcanically active country in Europe. It hosts three active volcanoes – Etna, Vesuvius and Stromboli – each of which has an associated geothermal system (subsurface hot water and gases). In theory, any of these could be used for geothermal power generation. But another of Italy’s volcanoes is attracting attention. Campi Flegrei, near Naples, is a volcanic caldera which last erupted in 1538. Most of the caldera is underwater, and it is considered to be dormant. Nevertheless geothermal systems are still active onshore and in a recent paper, scientists from the Vesuvius Volcano Observatory tried to find out if Campi Flegrei’s volcanic heat could be tapped…

For most of human history volcanoes have been viewed as malevolent forces. But since the advent of geothermal electricity in the early 20th century, our planet’s deep heat has started to be turned to our species’ advantage.

Countries like Iceland are already taking full advantage of their volcanic potential. The small island nation, home to around 30 active volcanoes, now derives one quarter of its electricity from the associated geothermal heat. Other nations should strive to follow this example.

One of them is Italy. The country has an impressive place in the history geothermal power – the world’s first geothermal generator was tested in Tuscany in 1904. Yet while the technology has blossomed elsewhere in the world since then, the exploitation of geothermal power in Italy remains extremely limited. But it has huge potential.

Italy is the most volcanically active country in Europe. It hosts three active volcanoes – Etna, Vesuvius and Stromboli – each of which has an associated geothermal system (subsurface hot water and gases). In theory, any of these could be used for geothermal power generation. But another of Italy’s volcanoes is attracting attention.

Campi Flegrei, located 10 km (6.2 mi) west of Naples, is a volcanic caldera which last erupted in 1538. Most of the caldera is underwater, and it is considered to be dormant. Nevertheless geothermal systems – including fumaroles and 250°C (482°F) aquifers – are still active onshore. And in a recent paper, scientists from the Vesuvius Volcano Observatory tried to find out if Campi Flegrei’s volcanic heat could be tapped.

Their simulation suggested that by drilling between two and four wells to a depth of approximately 2 km (1.2 mi), enough geothermal heat could be gathered to sustain a five megawatt electric plant

In the paper, the researchers used a computer model to predict what would happen if Campi Flegrei’s geothermal aquifers were drilled, and how much electricity such drilling could generate. Their simulation suggested that by drilling between two and four wells to a depth of approximately 2 km (1.2 mi), enough geothermal heat could be gathered to sustain a five megawatt electric plant. What’s more, since Campi Flegrei’s geothermal activity is spread over an area of around 100 sq km (39 sq mi), the region could potentially accommodate several such plants.

One of the factors holding back the expansion of geothermal power in Italy, and elsewhere in the world, is the associated seismic hazard. Geothermal power generation can require injecting water back into the aquifer from which it was extracted, a process which can generate small earthquakes. Encouragingly though, the authors of the new study estimate that the earthquakes caused by the (hypothetical) wells in Campi Flegrei would not be higher than magnitude 2.0, meaning that they probably wouldn’t be felt by humans.

Of course, humans should still be cautious when it comes to deep drilling – especially close to a volcano! But with the right expertise – and by following the example of Iceland – countries like Italy could soon be able to take advantage of their fiery geological location.

about the author
Robin Wylie
Freelance earth/space science journalist. Currently finishing off a PhD in volcanology at University College London.