As explained in the post “introduction to geothermal energy“, geothermal energy is heat energy originating from beneath the Earth’s crust. This heat is continually produced by the natural decay of radioactive materials such as uranium and potassium. According to US Department of Energy the amount of heat within 10,000 meters of Earth’s surface contains 50,000 times more energy than all the oil and natural gas resources in the world.
The areas with the highest underground temperatures are in regions with active or geologically young volcanoes. These “hot spots” occur at plate boundaries or at places where the crust is thin enough to let the heat through. The northern island of the Lesser Antilles possess a potential for geothermal site where according to Huttrer1999 virtually all the islands are underlain by active or dormant volcanoes. The islands of Saba and Saint Eustatius (Statia) of the Netherlands Antilles, Saint Kitts5 and Nevis, Montserrat, Dominica, Saint Lucia, Saint Vincent and the Grenadines, and the French territories, Guadeloupe and Martinique, forms part of the of the active volcanic arc of the Caribe Oriental and the Lesser Antilles.
From Saba in the north to St. Vincent in the south, active volcanoes and surface hydrothermal manifestations exist on each of the islands. According to Battodetti 1999 Dominica and St. Lucia, exhibits intense surface hydrothermal activity which marks the presence of high enthalpy geothermal systems—230EC at Wotten Waven in Dominica, and 300EC at La Soufrière-Qualibou in St. Lucia.
The thermal energy potential available in these volcanic islands makes them of interest for exploration. The majority of electricity on these islands is currently being produced by diesel generators and as a result, the costs of electricity are relatively high. The electrical needs of these islands are growing as light industry and tourism growth increases, and the use of an indigenous resource such as geothermal energy would decrease the cost associated with diesel imports.
Table 1: Showing geothermal Energy Potential in the Caribbean
Although geothermal resources are abundant on several of the islands, apart from Guadeloupe which has a 4.5 MWe binary plant, geothermal development is still in the early stages for several reasons. Dominica however, recently sign off on an initiative to construct a geothermal plant that will be be funded by the French, European Union and Dominican government at a cost of US $17 million. This project is expected to provide an alternative local energy source, in addition to exporting power to the neighboring French islands of Guadeloupe and Martinique.
Not only does geothermal resources in the Caribbean offer great potential, they can also provide continuous baseload electricity. According to the U.S. National Renewable Energy Laboratory, the capacity factors of geothermal plants—a measure of the ratio of the actual electricity generated over time compared to what would be produced if the plant was running nonstop for that period—are comparable with those of coal and nuclear power. With the combination of both the size of the resource base and its consistency, geothermal can play an indispensable role in a cleaner, more sustainable power system.