LONDON -- In recent months, a number of companies have announced plans to develop geothermal energy projects at locations across the Caribbean, including Nevis Island, Dominica and St. Vincent. Why is the Caribbean such a promising region for the development of geothermal energy facilities? And what are the prospects for the expansion of the geothermal sector across the region?
The electrical supply across much of the Caribbean is generated by expensive and polluting oil- or diesel-fired generators, prompting many of the governments across the region to look for alternative sources of energy. Although renewable energy sources such as wind and solar help to reduce carbon emissions, they are viewed by many in the region as providing a supply that is too intermittent — and have also been criticised for tending to be more expensive than fossil fuel generation methods.
According to Bruce Cutright, chief technology officer at Nevis Renewable Energy International (NREI), the Leeward Islands and the Eastern Caribbean are all “ideally positioned” for geothermal energy development — primarily because they lie near and above two continental plate boundaries where volcanic activity has created high temperature reservoirs “at sufficiently shallow depths to make their development reasonably practical and economically competitive with some other generation methods.”
"Because of this apparently plentiful resource base, we expect some of the islands to transition to geothermal energy generation. However, drilling and power plant construction is expensive and requires significant investment horizons. There will be no quick transition," said Cutright.
In an effort to exploit this potential, whilst simultaneously reducing costs and emissions, the Nevis Island Administration is currently in the process of contracting with NREI to provide the island with a more reliable supply of geothermal power. As Cutright explained, the Island of Nevis is “blessed with an attractive source of geothermal energy” that, at least at this stage, appears to be able to be developed “at a reasonable cost that will result in an electricity cost savings to the Island Government and to the population.”
Although there is still some work to be completed to define the physical characteristics of the geothermal reservoir on the island, Cutright believes that the most appropriate technology to use on the Island will be flash steam generators.
"High temperature steam will be produced from the deep geologic reservoir, directed through a steam turbine that will turn an electrical generator to produce electrical power," he said.
Final contracts for the Concession and Power Purchase Agreement with the Island's utility company NEVLEC are not yet complete, and Cutright stressed that it is too premature to talk about specifics. But he admitted that “it would be the intent of the Nevis Island Government and the electrical utility to work cooperatively with NRE International to produce electricity at a geothermal generating facility, distribute this power through the existing transmission network on the island, to serve the people and the industry on the island of Nevis.” He also warned that the similar projects across the Caribbean are likely to face a number of financial, institutional and physical challenges.
"Because of the small size of the markets on each island, it is somewhat more difficult to attract the capital investment necessary to construct and operate geothermal power plants," he said.
"The institutional challenges are many and varied, but the most common issue is that many of the island electrical utilities are locked into long term contracts that have no incentive for the power producers to develop more economical methods of generation," he added.
In spite of this, Cutright said that the Nevis Island Administration “has had the forethought to see the opportunity to restructure their generation methods by already adding wind as an important renewable component.” He revealed that it now intends to add geothermal “as both a renewable component and base load power supply,” whilst also maintaining diesel generators “as peaking and standby power supplies.”
“There is still much work to be done to characterize the geothermal resource on the Island, but initial estimates are that the resource on Nevis may be large enough to attract adequate capital investments, and the geographic location close to nearby islands may allow Nevis, if the reservoir capacity were to prove large enough to supply other islands, to expand the service area. Nevis is, therefore, potentially uniquely positioned for success. Some of the other Leeward Islands, in general, have similar attributes, and therefore similar opportunities," he added.
Ultimately, NREI believes that the Nevis Island Project is a “gateway project” for geothermal energy development in the Caribbean — and that Nevis will serve as an example for other islands to follow.
Iceland Drilling Company (IDC)
Elsewhere in the Caribbean, IDC is currently developing two exploratory geothermal energy projects on Dominica and Montserrat (image, right) to investigate the possible geothermal resource on each island — followed by a drilling program to drill production wells for geothermal electricity production. As Sturla Birkisson, senior vice president at Iceland Drilling Company, explained, the next stage will involve the set up of a steam turbine by an independent electricity developing company.
"Iceland drilling is not offering that part of the project, only the 'well construction' part of it. We will drill further wells if needed for further steam harvesting and for fluid injection," he said.
According to Birkisson, each project is being developed as a way for the communities on the islands to utilize local resources “to become independent of the import of fossil fuels to produce electricity from diesel generators.”