The hot springs of Petite Anse, an indicator of the geothermal potential of southern  Martinique (2012). © BRGM - Alain Gadalia

Assessing geothermal potential in the Dominican Republic

In June 2016, the BRGM began a one-year study to assess geothermal potential in the Dominican Republic, with a view to producing electricity via high-temperature geothermal fluid and/or extracting low to medium temperature geothermal heat for different uses.

An information sessionon geothermal energy  presented by the BRGM at the Ministry of Energy and Mining in Santo Domingo, 14 June 2016 (Dominican Republic). © BRGM

Like many Caribbean island nations, the Dominican Republic is highly dependent on oil for its electricity production. This new phase in geothermal explorations is justified by the island's tectonic context (Caribbean arc) and potentially favourable indications of geothermal resources  (discovery of 300 000 yearold volcanic zones and presence of hot springs emerging at 40°C).

Developing renewable energy from its own resources is an issue of major importance for the Dominican Republic and its economic development and energy independence”, says project manager Bernard Sanjuan. “Geothermal energy, if it could be available 24/7 at a competitive price,  would be a tremendous asset, but previous explorations had left too many points unresolved.”

The BRGM had conducted exploratory work for geothermal resources since the 1980s in the Dominican Republic, identifying four priority zones of which one, in a volcanic context on the Yayas de Viajama-Constanza axis (west of Santo Domingo), was particularly favourable. The Italian  company Electroconsult explored the zone in more detail in 1984 and proposed two borehole sites on the thermal gradient, but these were never drilled.

Electricity production for industry, agriculture and leisure

In the last few years, the BRGM has resumed its geothermal activities in the Caribbean at a sustained pace, for example with the development of the Bouillante field in Guadeloupe and its exploratory studies in Martinique and Dominica”, says B. Sanjuan. “We were already very active in the Dominican Republic (see article on page 8), so the BRGM was a natural choice for this study, which is funded by the Inter-American Development Bank (IDB) and conducted under the framework cooperation agreement signed in 2014 with the Dominican Republic's Ministry for  Energy and Mining.”

The four zones identified in 1980 will be studied for a year, with a particular focus on the Yayas de Viajama-Constanza zone. As B. Sanjuan explains, “we will be compiling and analysing a large quantity of bibliographic data, previous reports and information from the oil drilling database and the Sysmin database on mineral resources. The next phase will involve geological reconnaissance campaigns and geochemical and hydrological investigations to confirm the potential we have identified. Our subsidiary CFG Services will then take over with technical and economic  studies to assess whether the potential resources match need in the country.”

Electricity production via high-temperature geothermal resources (over 150°C) is not the only aim, however. Geothermal resources with lower temperatures will also be assessed for the production of heat and cold for industry, agriculture, fish farms and leisure activities.

The final phase will determine the relevance of additional studies”, says B. Sanjuan, “especially pre-feasibility and feasibility studies that will require geophysics surveys and drilling along the thermal gradient, and explorations to depths of several hundred metres.”The BRGM is being   fully supported by the Director of the Dominican Republic's geological survey, which has a team contributing actively to the project. “We are working with two geologists, two hydrogeologists and two specialists in Geographic Information Systems. Another aspect of our mission is to train and transfer knowledge and know-how to local staff working on the ground.”

*Study piloted by OLADE (LatinAmerica Energy Organisation)

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