  In 2017, the electricity mix of the Department of Mayotte included 5%
photovoltaic production, spread over more than 70 installations on the island,
and 95% diesel thermal production, provided by two power plants. Nevertheless,
since 2005, in order to diversify its electricity supply, the local authorities
of Mayotte set up a vast program to develop renewable energies, including the
evaluation of Mayotte's geothermal potential to produce electricity.In this
framework, BRGM started a program to explore the deep geothermal potential of
the department of Mayotte. The conclusions of the different studies confirmed
the idea of a strong potential under Petite Terre (Traineau et al., 2006;
Sanjuan et al., 2008; Darnet et al., 2019).Our present study aims at refining
the knowledge of the subsurface and the geothermal system potentially present
beyond a depth of 1000m. This new phase, carried out between 2021 and 2022
includes a geophysical measurement campaign accompanied by a fracture analysis
and the study of gas emanating from the ground.The different data set acquired
during the campaigns are analysed and interpreted jointly with the data
acquired in the framework of the monitoring of the exceptional seismo-volcanic
activity observed since May 2018 off the coast of Mayotte.The result of this
analysis is a 3D geological model of the structure of the island of Petite
Terre, completed by a hydrothermal model of the functioning of the geothermal
system, with the aim to help in locating the most favourable zones for
geothermal exploitation.
