Geothermal energy in the Caribbean

In a volcanic region like the Caribbean, geothermal energy represents one of the most promising sources of green energy.
27 November 2015

This series of videos was created as part of Phase 2 of the European Caribbean Geothermal Energy project aimed at establishing an overall Caribbean policy for the development of geothermal energy.

Geothermal energy, one of the pillars of the energy transition

In a volcanic region like the Caribbean, geothermal energy represents one of the most promising sources of green energy.

Phase 2 of the European Caribbean Geothermal Energy project aims to establish an overall Caribbean policy for the development of geothermal energy.

© Géothermie Caraïbe

Geothermal Energy in The Caribbean 2

Another Form of Electricity

In 2013 for the first time, the world's renewable energy capacity overtook that of fossil fuels. In 2013, we built more solar, wind, geothermal and biomass power plants than gas and oil plants. Something is happening.

The revolution is here. Fossil energies are giving way to renewable energies. In a volcanic area like the Caribbean, geothermal power is one of the most promising green resources.



The issue of fossil energies is a strategic problem. We currently depend on an increasingly rare product, one that pollutes and is increasing a financial burden, for households, industry and nations.

Developing Martinique's renewable energies means buying less oil. Till now, I haven't bought oil from either Martinique or France. So it's money we keep.

If future tensions arise about supplies, the priority market to supply will not be Guadeloupe. Others will come before us. It's important for small territories like ours, as with food production, to be self-sufficient in what we produce and consume.

Today, Guadeloupe and Martinique and most Caribbean islands are about 90% dependent on imports of oil or coal to produce electricity. It's a huge burden on the trade balance. But not only that.

People here live mainly on the coasts and are very concerned by rising sea levels. Most large populations are on the coast. We need to consider the potential consequences of global warming on atmospheric circulation issues, such as cyclones.

We complain about the effects of climate change. To complain, you first need to be exemplary.

To give you an idea, our current electricity consumption potentially produces 15 times more greenhouse gas emissions than the national average because of fossil energies.

One way to reduce the environmental impact of electricity is to produce less.

The 1st pillar, both the least obvious and particularly important, is the control of energy consumption. Before producing energy, we must avoid wasting it.

Until we master consumption and reverse the growth curve, all our endeavors with regard to energy production and fighting climate change will be in vain.


Energy transition is also about developing renewable energies. In this matter, the Caribbean has an impressive potential. Solar, wind, hydraulic, biomass and geothermal energy. This range of purely local resources means a phasing out of fossil energies can be envisaged.

Our territories are hotspots of biodiversity. We need to preserve the environment. Working towards energy transition is also about giving ourselves a way to transform what are often "counter" economies into economies that harness biodiversity to promote growth.

The development objectives for renewable energies are very ambitious. Launched in late 2012 as part of Guadeloupe's regional energy plan, the aim is for Guadeloupe to achieve energy self-sufficiency by 2050, using solely renewable energies.

To meet these objectives, regional schemes in Guadeloupe and Martinique provide for parallel development of local renewable potential. In this context, intermediate targets for 2030 in Guadeloupe envisage a leading role for geothermal energy.

Geothermal will account for 34% of all production. Why? Geothermal energy is a stable, continuous source unaffected by climatic variations. In this field Guadeloupe is a trailblazer as it has the Caribbean's only operational geothermal plant.

The Caribbean, particularly Martinique, is fortunate to have deposits. The potential targeted by 2030 is around 50 MW, meaning geothermal energy will have a key role in tomorrow's energy mix.

Geothermal energy is a blessing. We are a string of volcanic islands. This untapped resource - hot water - sits in the ground. Potentially, it can produce steam to produce electricity. It's right here, below our feet. We don't need to look elsewhere.

Geothermal energy is now well established in Central America and California. California has the world's largest geothermal power station, producing 1 GW. That's 4 times the maximum power on Martinique's grid. So it can work!

Geothermal energy is renewable and does not produce greenhouse gases. It's a basic energy, meaning it is available, it works every day, 24/7, and doesn't depend on external factors like sun or wind.

Two main types of energy supply electrical grids: variable flow energies - sun, wind, tidal - whose availability varies with the climate, and basic energies. These are able to supply the grid continuously with no loss of power. That's the case for fossil, biomass and geothermal energies.

The idea is to rely on basic energies, i.e. non-intermittent energies. This is the great thing about geothermal energy and biomass. So it's an attractive prospect to develop these basic energies while supplementing them with intermittent energies.

Of course it's time to use what we have a wealth of. We cannot continue to use oil and coal while we have sun, wind, biomass... Even the waste we don't know what to do with can produce energy. We have geothermal.

The advantages and wide availability of geothermal energy across the territory make it an obvious and key pillar of energy transition strategy in the islands of the Lesser Antilles. So why wasn't this resource developed sooner? Its potential was known about 50 years ago.

Geothermal energy requires huge but extremely profitable investment. It's the cheapest energy we know of that's available in the Lesser Antilles. But the huge investments are risky. A geothermal program starts with drilling. It's like drilling for oil. We know about the reservoir and the potential but at some stage you need to sink holes, with - unfortunately - a 2 in 3 chance of failure.

The risks at startup include geological risk. Geological risk is the possibility that despite all our studies, we cannot find an exploitable resource. So the risk is high at the outset, decreasing through the different stages. Until we drill to check on a resource, there will always be a risk.

Each drilling project costs between 2 and 4 million euros with the risk that it is dry. Then there's plant construction, exploration... All very costly.

First, you need motivated territorial partners. Second, you need motivated technical partners to ensure good project design.

BRGM's idea from the outset to which we have subscribed, was to say that in Guadeloupe - and in Dominica - you have the required potential critical mass to attract major industrialists and produce a showcase that will provide public exposure.

Plans to set up a 100 MW geothermal power plant in Dominica in partnership with Guadeloupe and Martinique is the first in a series of major projects in Saint Kitts, Montserrat and elsewhere.

There is the will to create what I believe is essential: Caribbean energy cooperation. Dominica has a deposit. As Caribbean islanders, can we say that the Dominican deposit is for Dominica only?

Providing power to 2 neighboring Guadeloupe and Martinique would be a source of income. Geothermal energy could be like oil and allow Dominica's government to fund improvements in infrastructure and in its people's lives.

In the near future, along this interconnected stretch of Martinique, Dominica and Guadeloupe, we will have electricity being exported to the 2 territories. It's a revolution for us all.

Far from affecting only Guadeloupe, Dominica and Martinique, the plan to connect the 3 islands paves the way for a possible Caribbean-wide grid.

The existing broadband network was initiated by a Guadeloupe company running a broadband cable from Puerto Rico to Trinidad. Tomorrow, this idea of interconnecting all the Caribbean for the production of electricity is very much in the pipeline. The World Bank did a study on electrical interconnection simply because it enables larger grids. It's far easier to manage, costs less, is more stable... It's all positive.

We are known as ZNI: non-interconnected zones. We will become interconnected zones on a global scale. Thanks to volcanoes which until recently generated fear, the nations, states, and peoples of the Caribbean will be able to act together, just as the peoples of Europe and America already do.

These joint projects for industrial and environmental development are helping to redefine what it means to be Caribbean.

The July 2015 law on energy transition reaffirms the ambitious objectives for France's overseas departments, targeting energy self-sufficiency by 2030.

The development of geothermal energy in the Caribbean is vital.

Geothermal energy, an opportunity for the Caribbean

In the string of volcanic islands that form the Caribbean Arc, geothermal energy is a source of energy with great potential.

Phase 2 of the European Caribbean Geothermal Energy project aims to establish an overall Caribbean policy for the development of geothermal energy.

© Géothermie Caraïbe

Geothermal Energy in The Caribbean 2

Another Form of Electricity

When you come here to bathe, it's for both your physical and mental health. As soon as you soak in the water, you feel better. Even if you were preoccupied or stressed when you got here, when you get out, you feel good.

This means that it cleans and purifies you from the inside.

Long before the development of geothermal power, geothermal heat was a source of well-being for the Caribbean peoples. On the volcanic islands of the Antilles arc, geothermal energy comes straight from the Earth's bowels, but its true potential is still unknown.


Inspiration from the Caribbean

The history of the Antilles arc began almost 50 million years ago during the Eocene Epoch. It's quite complex. The arc was formed by the meeting of two lithospheric plates.

The Atlantic plate slid under the Caribbean plate at an average rate of 2 cm per year. As it sunk beneath the upper mantle, the Atlantic plate freed pockets of magma that rose to the surface, forming volcanos that would become the islands we know.

In Guadeloupe, studies carried out by universities and the BRGM show that the resource is localised in zones with an intersection, where the fluids can easily convect. The Bouillante resource is right there.

The reservoir that supplies the Bouillante plant is located in the heart of the Bouillante Chain, at the intersection of several faults, the largest of which joins Montserrat Island to the North-West.

Geothermal potential is the intersection of various parameters. You need recent volcanic activity. This is the heat source that provides you with hot water. But this water must be able to infiltrate the reservoir and come into contact with the hot rock in order to reach temperatures of 200-250 degrees. So you need faults, because they enable the circulation of precipitation runoff, or the infiltration of sea water into the reservoir.

The deeper you go, the higher the temperature. That's the geothermal gradient. A normal gradient varies between 15 and 45 degrees per kilometre. In zones that can be exploited geothermally to produce electricity, it's far higher: up to 100 degrees per km. In certain places, like Thomas Springs or Bouillante, liquids sometimes rise to the surface.

In the Bouillante zone, subterranean fluids can reach up to 250 degrees. In Dominica's Boiling Lake region, underground temperatures reach up to 300 degrees.

Here we are at Thomas Ravine, where there are hot springs. You can see these volcanic deposits. This is volcanic rock. The geological formations are run through by this fault right here, which has formed these slopes.

At the Thomas hot springs, the hot water source is situated precisely on a fault in the Earth's crust.

It's orientated East-West. Via this fault, in the centre of these rocks, which have a cool, normal temperature, fluids circulate. Some of these fluids come from rainwater infiltration into the rock, and some come from sea water infiltration. This blend runs deep inside the rock. It heats upon contact with the rock and comes back out here.

You can see swirls, like in a cooking pot, with hot water and cold water below. The waves mix them up and the fluids come back out here through the fault, not over there. And of course, the fault continues beneath these people, who are taking advantage of the water's properties. And the fluids run off along the fault.

Apparently the Bouillante region is not the only zone favourable for geothermal uses in Guadeloupe. Likely potential has been detected near La Soufrière and Vieux Habitants. There is also potential at the well-known sites of Ravine Chaude and Sofaia.

These hot springs are good for illnesses like bone disease, aching muscles, cramps, sciatica and rheumatism. After the chikungunya epidemic, 300 or 400 visitors came here. Because people who'd had this disease suffered from cramps in their fingers and toes. And after 3 or 4 baths, they felt fine.

Martinique has its own hot springs too, which signifies geothermal activity. Prospecting studies have revealed potential for low-temperature geothermal energy.

Here we are at Lamentin Airport. We have surface indications of underground geothermal activity. This here is a hot source. It's close to 45 degrees with gas emanations. We see the same phenomenon in several places, which signifies the geothermal potential of the entire Lamentin plain.

Drilling took place in the late 90s here at Lamentin, because there is a geothermal reservoir. Unfortunately, it wasn't hot enough.

Temperatures are between 80 and 90 degrees. It's not enough to produce regular geothermal electricity. However, this heat can be valorised, since the well was dug in the basin of an industrial zone.

It's a question of producing cold water and hot water, which are distributed via cold and hot networks. This technology is totally mastered by French industries. Why? Oddly enough, in Île-de-France, a good one-third of collective urban heating comes from geothermal power.

This is the industrial zone where geothermal drilling took place in 2001. This borehole is 700 m deep and the water temperature is 90 degrees. The advantage of a borehole in an industrial zone is that the resource can be used to respond to the direct needs of the buildings and neighbouring businesses.

But Martinique's underground temperatures are not all low. Recent studies show that there could be potential for electricity production.

We have possible leads for high-enthalpy production in 2 zones. One is located in Petite Anse, the other in Morne-Rouge. We suspect the presence of interesting geothermal resources.

Geothermometric calculations show that the first reservoir at Chaude River is close to 180-200 degrees. And the second reservoir at Picodo River is around 155-180 degrees. These temperatures could enable electricity production.

The next step is to verify and confirm these resources. But we must remain prudent. We are expecting to find 10 to 20 MW of geothermal energy.

Mount Pelée and Anses d'Arlet are both sensitive zones. Mount Pelée is a preserved national heritage zone. It belongs to the people of Martinique. There's a true desire to be careful what we do, not just go in with financial or industrial goals. And Anses d'Arlet is very touristic. We can't just disfigure a gorgeous zone that we enjoy every day for power. At the same time, we can't make sanctuaries of them to the detriment of the economy in Martinique or its job market.

Like in Dominica, geothermal potential in Martinique lies in ecologically sensitive zones. Geothermal projects will need an efficient accompanying strategy to combine development and preservation of natural surroundings.

Bouillante, the capital of geothermal energy

Bouillante, in Guadeloupe, is home to the first geothermal power plant in the Caribbean islands.

Phase 2 of the European Caribbean Geothermal Energy project aims to establish an overall Caribbean policy for the development of geothermal energy.

© Géothermie Caraïbe

Geothermal Energy in The Caribbean 2

Another Form of Electricity

My name is Jules Cairo and I'm from Bouillante. I worked at the plant starting in the 70s up until 2010.

Bouillante or "Boiling", a small town in Guadeloupe, is aptly named. The properties of its hot springs are well known to locals. Today, Bouillante is the headquarters of the first geothermal power plant in the Caribbean.



The plant is right behind the old soccer field. Behind the goalposts, there were bubbling hot springs with boiling water.

Back in the day, everyone called it the "swampland". It was a sort of mangrove swamp filled with hot springs. The whole area, even the road running behind, and the vanilla plants, was covered with hot springs.

This once vast sulphurous swampland is now a geothermal power plant, Géothermie Bouillante.


In the 60s, the BRGM started carrying out studies to understand, characterise and define the geothermal potential in Guadeloupe. There were various phases. A first plant was built in '86.

Initially, it was experimental. We installed this turbo-generator set to see where we could go with it. We produced for years, until 2005.

At the time, development strategies didn't exist. That came along much later, in around 2006. It began when Bouillante 2 started up. The cost of energy was rising and the end of fossil fuels was looming on the horizon. So we were looking to develop renewable energy forms.

The discovery of two more wells up there, with a high enough steam output, made them decide to start up a second 11 MW turbine.

The challenge for Géothermie Bouillante was to turn the plant into a business. To truly produce electricity with geothermal energy. And they did it. In 1998, they succeeded. That's when the board of Géothermie Bouillante decided to drill two additional boreholes on the BO-4 platform. The two boreholes were a total success in 2000. So we had two productive boreholes for the construction of B2.

Wells platform

Here we have two production wells and two observation wells. A two-phase fluid runs through the pipes, a mixture of water and steam. When it reaches the wellhead, the fluid is 169 degrees. It goes through the valves, which are sort of like faucets. Next, the fluid is transported down below in the pipes.

To harness the Earth's heat, wells are drilled. In Bouillante, the wells push to the surface what is called a "two-phase liquid": a blend of pressurised water and steam.

This is a geothermal power plant. The difference here is that we don't need a boiler furnace like in a traditional thermal plant. We don't need to heat with fuel, such as coal, gas or bagasse, which we use here, or nuclear energy elsewhere, to heat the water and vaporize it in order for the steam to power a turbine.

With geothermal energy, the boiler is the Earth. Once on the surface, the two-phase fluid is sent to the separator. As its name indicates, it separates the steam from water. The pressurized steam is sent to the turbine to power the blades, which in turn activates the alternator, a gigantic dynamo that produces electricity.

Control Room

The steam is sent from the turbine to the condenser, where it is cooled with sea water and injected into the bay at a temperature less than 45 degrees, as stipulated by regulations. The water from the separator is directly pumped back into the reservoir. Despite all the machinery, geothermal energy remains one of the most reliable and clean renewable energies.

The liquid from the plant comes from the Earth, so it's rich in various minerals. Plus the salt and high temperatures.

So people were afraid that an imbalance would be created and the marine ecosystems would be fragilized, upset, or ever disappear. But the outcome is that since 2008, there has been no deterioration. No negative impact from the plant on marine life in the bay.

But hot water evacuation is a technique that's used less and less. Today, modern plants are equipped with reinjection systems to maintain the reservoir's level and pressure. In Bouillante, a partial reinjection unit was added to ensure the resource's sustainable exploitation. But the greatest inconvenience of a geothermal plant is perfectly invisible: the smell.

People say it smells like rotten eggs. Yes, it does. But we're very happy. When it smells, we're producing. It's good for us. For the locals, not so much.

To resolve this inconvenience, Géothermie Bouillante recently installed a thermal oxidation system to limit unpleasant emanations. After having been an essential experimental lab, the Bouillante plant is now an operational production unit capable of delivering up to 15 MW of electricity to networks. But geothermal power in Guadeloupe has not nearly reached its potential.

Geothermal power currently represents about 4% of the energy mix. However, we believe it has major development potential. To start with, we believe that the potential in the Bouillante zone could enable us to triple our current production. This would increase the ratio in the energy mix to about 20% by 2020, if we manage to exploit it fully.

A site just north of the bay has been chosen for a prefeasibility study. The study is not yet finished, but we can already foresee a potential of 30 MW.

Throughout the Caribbean arc, geothermal reservoir projects are in the development phase. If Dominica is well along,

Saint Kitts and Nevis also anticipate building plants, and exploratory programmes are underway in Montserrat, Saint Lucia, Martinique and elsewhere.

We knew that the neighbouring islands had potential. From the start, the idea was to continue developing Bouillante, and develop the islands closest to us. That means, Dominica, and Saint Lucia for Martinique.

Geothermal power is a common characteristic in many Caribbean islands, which are volcanic. Here in Guadeloupe, we are precursors. We already have experience, which we hope to share throughout the Caribbean.

We believe that with the BRGM's current orientation, and the arrival of new partners, we can build a referential system for environmental integration and social acceptation that can be exported in the Caribbean.

We also accompany regional councils with more international projects in the Caribbean, because geothermal potential exists on other islands, like neighbouring Dominica. If seen through to completion, a current project could increase the portion of geothermal energy to such an extent that it would represent the primary source of renewable energy and one third of our energy mix. As you see, the development potential of geothermal energy is huge. In Guadeloupe, we believe very much in this energy form.

Dominica, the 100% green island

The small volcanic island of Dominica is poised to become one of the very first countries to produce electricity from a 100% renewable source.

Phase 2 of the European Caribbean Geothermal Energy project aims to establish an overall Caribbean policy for the development of geothermal energy.

© Géothermie Caraïbe

Geothermal Energy in The Caribbean 2

Another Form of Electricity

Situated between the Atlantic Ocean and the Caribbean Sea in the Lesser Antilles, the small volcanic island Dominica is about to become one of the first countries to produce 100% renewable electricity.


The 100% Green Island

Despite this ecological awareness, not easy for a tiny independent island to live without "non-natural" energy.

Importing diesel for electricity production costs Dominicans 17 million USD each year, almost 10% of the country's GNP.

Indeed, Dominica has a goldmine of renewable resources, starting with its 365 rivers. But the island's most important resource is barely visible to the naked eye: water vapour.

Geothermal energy: an underestimated resource found in most recent volcanic zones. Wherever there's an active volcano, there's most likely a resource that can produce energy. And in the Caribbean arc, there's no lack of volcanos.

A European cooperation with neighbouring French islands started up Dominica's geothermal energy programme. Feasibility studies carried out by Guadeloupe, the ADEME and BRGM, with European funding, estimated the potential in Roseau Valley at nearly 120 MW of electricity. This largely exceeds current needs in Dominican households.

Within 2 years, Dominica will replace nearly all fossil fuel electricity production with clean, economic and renewable energy.

A project is currently being studied where underwater cables would link Dominica to its 2 big neighbours, Guadeloupe and Martinique. Geothermal electricity would become one of Dominica's most important export products, along with soap. In the valley, opinions are divided. If many people see an opportunity for development, others question the impact of such a project on their environment.

A Guadeloupian consultancy was appointed to anticipate and monitor the environmental impact of geothermal development in Dominica. The study shows that, contrary to the situation in Bouillante, the natural environment

here is immense. There are forests and valleys that haven't even been explored. The natural resources are exceptional. We'll really need to...

- Take this into consideration.

- Yes, because... there are rare and endemic species.

The tropical forest that covers most of the island is one of Dominica's wonders and a main tourist attraction. But it will have to make room for the new infrastructures.

Despite recent industrial and touristic development, Dominica has preserved much of its magnificent natural surroundings. The installation of a geothermal industry has become a major development issue. Geothermal energy is both an asset for the country's economy, as well as a fabulous opportunity to continue preserving its precious environmental quality.