Resource World Magazine

58 www.resourceworld.com o c t o b e r / n o v e m b e r 2 0 1 4 ALTERNATIVE e n e r g y r e v i e W Developments in Alternative Energy by Jane Bratun the PRoMiSe oF geotheRMaL eneRgY PRodUCtion in the CaRibbean Bruce L. Cutright, CTO of Englewood, Florida-based Nevis Renewable Energy International, L.L.C. (NRE), says most of the Caribbean Islands are blessed with ample geothermal resources capable of meeting all of their energy needs, but they have a his- tory of relying on imported fossil fuels. Wind and solar appeared to be alternatives to imported fossil fuels, but these alternatives are intermittent and without adequate energy storage methods. The local utilities are left depending on fossil fuels and energy costs among the highest in the world. Nevis, (the Federation of St. Christopher and Nevis), a small island that forms part of the inner arc of the Leeward Islands chain of the West Indies, has boldly embarked on a path to solve this problem, and as a result, has an opportunity to escape from the tyranny of high electricity prices while reducing their carbon dioxide emissions and providing new jobs and new tech- nologies for their citizens. The solution is geothermal energy production. Geothermal energy is heat derived from magmatic or volcanic areas where near surface molten rock has heated circulating ground water to temperatures near or above the boiling point. Thermal energy from these sources can be extracted to drive electric genera- tors. The geothermal resource base is enormous with conservative estimates of extractable geothermal energy ranging from hundreds to thousands of billions of barrels of oil equivalent, or, measured another way, could produce trillions of megawatt-hours per year. The geology of the Caribbean Basin is promising for geothermal energy produc- tion and as such, represents a gold mine for the islands greater than the oil fields of the Middle East. And, what's more, geothermal energy is continuously replaced by the natu- ral heat flow from the Earth's interior; when the Middle East is depleted, the Caribbean will still be providing constant, renewable energy. Recent advances in drilling technology have opened the prospect of producing geo- thermal energy in areas previously thought to be too difficult or too expensive for such energy production. What has changed is the massive investment that the petroleum industry has made in drilling methods and in rock formation stimulation is applicable to extracting heat from deep geologic formations, and with this, the economics of geothermal energy production have improved significantly. Deep production wells were normally considered uneconomic if they were greater than 5,000 feet or 6,000 feet deep; now, an economic production well can be twice to three times this depth and still produce energy at rates well below the cost of fossil fuels. Economics is the key, and where the cost of electricity pro- duced by diesel or other renewable technologies results in power costs of more than US 30 or 40 cents per kilowatt-hour, geother- mal energy production has the potential to reduce this by half or more. The ultimate comparison of the various power pro- ducing methodologies is the "levelized cost of energy" (LCOE). Geothermal energy is now less costly than oil, advanced coal fired generators, wind, concentrating solar, photovoltaics and only a few cents per kilowatt hour more expensive than advanced natu- ral gas turbine generators. The graph is a compilation of the LCOE costs provided by the US Department of Energy, published in 2014 for power genera- tion in the US. This reflects the actual cost, and not what would be necessary to charge to a retail customer, but retail sales rates in the range of 15 to 20 cents per kilowatt-hour are certainly pos- sible. Every site is different, however, and it is important to look at the local situation. The cost of transmission lines and mainte- LCOE Costs for Power Generation – 2014

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