Deep Wells for OTEC Application

Deep wells were evaluated as an alternative to conventional cold-water-pipe technology for small-scale open-cycle ocean thermal energy conversion (OC-OTEC) plants to produce fresh water and electricity. Since the piping for cold water in an OC-OTEC plant can account for as much as 40%-60% of the construction cost, a unique geological feature of Florida, called the Boulder Zone, was investigated. Located at a depth of approximately 3000 feet (915 m), the Zone contains cold seawater from the bottom of the Florida Straits. Potential sites for an OG-OTEG research facility using a deep well for cold water and a conventional power plant for warm water were evaluated. Five power plants and more than thirty deep wells were identified. It was concluded that the deep well concept for full scale OTEC plants is a viable alternative, but cannot be used in southeast Florida because of sewage injection into the Boulder Zone. An abandoned deep well located at Marathon, Florida was identified as a possible location for an OTEC research facility.