Geophysical imaging of a volcano-hosted geothermal system unravels suitable sites for drilling

What is it about?

Volcano-hosted high-temperature geothermal systems are powerful resources for renewable electricity generation. We use a geophysical method called magnetotellurics to image the 3-D electrical conductivity distribution beneath the power-producing Aluto-Langano volcanic geothermal field in Ethiopia. Subsurface electrical conductivity imaging allows to identify the magmatic heat source and the distribution of hydrothermal alteration minerals. Simultaneous 3-D imaging of these characteristic features allowed us to infer the hydrothermal flow patterns and upflow zones in a magma-driven geothermal reservoir. Our study explains strong well-to-well gradients encountered at the geothermal field and shows why the first two wells were not productive. Furthermore, it proposes new prospective drilling locations that can expand energy production.

Featured Image

Photo by Leti Tamrat on Unsplash

Photo by Leti Tamrat on Unsplash

Why is it important?

Geothermal energy is a baseload renewable energy, and it could be a major source of energy in countries along the East African Rift that host numerous active volcanoes. However, until today most of the geothermal potential remains untapped. Harnessing these geothermal energy resources could provide an affordable and homegrown renewable energy solution for regions with low levels of electrification. Our study of the Aluto-Langano geothermal field in Ethiopia shows how modern 3-D magnetotelluric imaging can help in de-risking geothermal projects. This technique can be adapted for other volcanic geothermal prospects around the world with similar geological settings.

Perspectives