Sea Technology

APR 2018

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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16 ST | April 2018 T ropical islands and coastal regions have population centers near the ocean and fast-growing energy de- mands. They also have the advantage of ideal conditions for deploying ocean thermal energy technologies. Ocean thermal energy, which can be used to produce electrici- ty, is generated from the temperature difference between cold, deep ocean water and warm surface water. The emerging ocean thermal energy conversion (OTEC) industry has the potential for fast growth with such a large segment of the world's population living near the ocean. Bluerise, in particular, is focusing on development of large-scale, low-cost, sustainable pow- er and air-conditioning in the tropics. The company has advanced OTEC technology that provides reliable pow- er year-round, day and night. While our offices are in Delft in the Netherlands and in Aruba, we are currently developing projects in Curaçao, Jamaica, Colombia and Sri Lanka. Seawater District Cooling Bluerise has designed, built and tested its OTEC pow- er cycle together with Delft University of Technology, with the goal of increasing technical and economic ef- ficiency. The core innovations lie within the power cy- cle of OTEC, applying a cutting-edge working fluid that consists of a mixture, in contrast to the pure ammonia working fluid that is used by other OTEC technology. The test performance of the technology is proof of the work- ing principle and validation of our technology enabling lower costs per kilowatt-hour produced. OTEC plants of a modest size (i.e., 10 to 25 MW) can now be competitive in many islands and remote regions, where electricity is relatively expensive at $0.20/kWh or higher and often powered by diesel/heavy fuel oil gen- erators. The market for OTEC will expand as the price for the technology decreases with advancing technology. Independent estimates show that just by reaching econ- omies of scale, OTEC installations can reach a levelized cost of electricity as low as $0.07/kWh. We continue to develop our OTEC system and have crafted a roadmap for the scale-up of our technology in preparation for our first pilot under real-world conditions in Curaçao in 2019. A commercial seawater district cooling (SDC), or sea- water air-conditioning, project will be part of our OTEC development. An SDC system can make synergetic use of an OTEC pipeline that brings up deep seawater at a low temperature. This cold seawater is passed through a heat exchanger, where freshwater is chilled and distributed through a closed loop to a building's cooling system, re- placing conventional chillers or cooling towers. The sole use of electricity comes from the pump, which consumes as little as 10 percent of the amount of electricity used by a conventional chiller. An SDC system relies on a sustainable and predict- able ocean energy resource that can provide coastal cities with an opportunity to significantly reduce their energy costs. SDC is not dependent on the outside air temperature or humidity but on the consistent supply of cold, deep seawater. This eliminates extreme spikes in power demand. SDC's advantages include: cost benefits from reduced operating costs with cooling that is 10 times more effi- cient compared to traditional comfort cooling; stability in future energy costs by using freely available deep sea- water; reduction in peak power demand in the electricity grid; and significant reduction in CO 2 emissions. Having the deep seawater infrastructure in place, the projects can grow into a so-called "ocean ecopark," in- spired by the Natural Energy Laboratory in Hawaii and similar undertakings in Japan and Taiwan. An ocean eco- park is a sustainable industrial park with high-tech pro- duction and research facilities relying on the availability of deep seawater. Apart from cooling and electricity production, deep seawater would be used for efficient freshwater produc- tion, agriculture and aquaculture, to name some exam- ples. OTEC Market on the Rise Ocean Thermal Energy for Power, Cooling By Berend Jan Kleute

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