What lies beneath: geothermal energy in Dominica

Dominica, the Antilles’ youngest island, is shaped by awesome volcanic forces beneath its surface — the key to an ambitious and sometimes controversia

Dominica’s Valley of Desolation, despite its name, may hold the key to the country’s energy independence. Photograph by Images DominicaThe grey waters of Dominica’s Boiling Lake are heated by an underground chamber of magma. Photograph by Images Dominica

Dominica’s Valley of Desolation is actually a place of great hope — if you know what you are looking at, that is. This desolate, moss-covered rock valley floor is wreathed in mists of steam, the result of very hot water being pushed up through volcanic mini-geysers and fumaroles (cracks in the Earth’s crust). These hot springs, for which Dominica is renowned, come in shades of grey, blue, green, yellow, orange, brown, and black — the residue of mineral deposits that have seeped out of the Earth into the stream beds.

You pass through the valley en route to Dominica’s most alluring natural sight: the Boiling Lake, a 207-foot-wide flooded fumarole, which sits inside a deep basin. A chamber of molten magma beneath the lake heats its grey waters to temperatures that cause the centre to bubble alarmingly. Along the edges, the temperature ranges from 82º to 91.5º Celsius.

While many Caribbean nations are looking upwards to the sun for an alternative source of energy, Dominica is looking in the opposite direction: down. The last island to be formed in the Caribbean, about twenty-six million years ago, Dominica was created by volcanic action. It lies on two opposing tectonic plates, which explains why its highest peak, Morne Diablotins, soars to 4,747 feet. The most mountainous island of the Lesser Antilles, its volcanic peaks are the cones of lava craters. Dominica is composed almost entirely of volcanic rocks, and it is also the most volcanically active island, with nine potentially active centres.

All of which means that Dominica is a hotbed of geothermal energy — perfect for exploitation.

Beneath our feet, the Earth is silently (and sometimes not so silently) generating enough heat to supply all of humanity’s energy needs. At its core, temperatures can reach a mind-boggling 5,000ºC, the result of radioactive decay of minerals and the original processes that formed the planet. The heat is conducted to surrounding rock, which can melt due to the temperature and pressure, creating magma. This in turn heats rock and water in the crust, sometimes up to 370ºC. The geothermal gradient — the difference in temperature between the core of the planet and its surface — drives a continuous outward conduction of thermal energy.

Until recently, geothermal power generation was limited to areas near tectonic plate boundaries. However, advances in technology have dramatically expanded the range and size of viable resources. For example, in Iceland, which has seventy years of geothermal experience, ninety per cent of homes are heated using geothermal energy, and it is used by most industries. There’s even a restaurant where all the food is cooked with steam rising directly from the earth. Although the wells release greenhouse gases trapped deep within the earth, these emissions are much lower per energy unit than those released by fossil fuels.

In 2008, a European Union–funded exploratory programme found that the geothermal resources in the Wotten Waven area of Dominica could potentially generate 130 megawatts of electricity — enough to supply the entire island with green energy, and maybe even export some too.

Experts from Iceland were brought in to verify the reservoir capacity and the quality of the geothermal fluid. They estimated that the Laudat-Wotten Waven geothermal field was about fifteen square kilometres in extent, with temperatures ranging between 250º and 300°C. Alongside the government of Dominica, the project is being financed by the French Development Agency and the European Development Fund. The French joined the project in the hope that Dominica’s geothermal field would be able to produce enough electricity to supply their nearby territories, Martinique and Guadeloupe, with fifty megawatts each, via undersea cable. If successful, the strategy would save the French government one hundred million euros per year in fuel subsidies.

The Martinique-Guadeloupe deal was dealt a serious blow in April 2013, when Electricité de France (EDF), the largest utility company in the world, and the sole electricity company in Guadeloupe and Martinique, withdrew from the project. EDF was supposed to have built and operated the electricity-generating plant in Dominica. But the French Development Agency is prepared to finance the construction of a smaller initial fifteen megawatt geothermal plant to provide electricity for local consumption, and the French government is still interested in financing a larger plant and in buying electricity from Dominica. Meanwhile, three strategically located exploratory wells, ranging from one thousand to two thousand metres deep, have already been drilled, with plans for more drilling in the works.

Environmentalists have voiced concern over the potential impact of deep drilling on Dominica’s water table, and the release of noxious gases. However, the government of Dominica has already invested more than US$12 million in developing the geothermal industry, and has sought the advice of the Clinton Climate Initiative on the way forward. The island’s ambassador to the United Nations, Vince Henderson, told the sixty-seventh session of the UN General Assembly in October 2012 that “Dominica’s energy initiative has the potential to transform its economy and to improve the quality of life of its people.”

In fact, if the project is a success, it promises a major impact on Dominica’s carbon footprint. As Henderson explained, “We anticipate that by 2017 all of our electricity needs will be met by a combination of sources: hydro and geothermal. By 2020 we expect to be exporting electricity to our neighbouring islands via submarine cables. This, coupled with our sustainable development practices, means that Dominica will be not only carbon neutral, but carbon negative, by 2020.”