View non-flash version
www.sname.org/sname/mt October 2012 Ocean thermal energy conversion (OTEC) is likely familiar to marine engineers and naval architects in the U.S. because it piqued the interest of many developers in the 1970s. OTEC is a mature technology based on sound thermodynamic prin- ciples?harnessing the temperature dierential between warmer, surface sea- water and colder, deep seawater. OTEC has well-documented performance at the small and pilot scale but a commercial scale plant has not yet been commissioned. Activity is still ongoing in the U.S. and abroad with key challenges remaining: cost effective fabrication of the cold water pipe (typically extending some 1,000 m), understanding of the potential environmental impacts of the discharge plumes, and overall system e- ciency and cost. Salinity gradient devices capture the potential energy difference between salinity concentrations in salt and fresh water. At this stage, most salinity gradi- ent devices are still in the experimental phase, although a 2-4 kW prototype power plant has been constructed in Norway. Key challenges for this technology include membrane technology and increasing the power density such that it can be consid- ered a viable commercial solution. Resource assessments In early 2012, the U.S. Department of Energy released reports documenting the results of wave and tidal power resource assess- ments. In the U.S., the overwhelming MHK resource is wave power (potentially up to 400 GW), followed by tidal currents (60 GW) and free-owing rivers (preliminarily esti- mated at 40 GW). e resource assessments indicate that that wave and tidal energy can capably contribute to meeting the nations electricity needs, potentially providing up to one-third of the nations total annual elec- tricity usage. The West Coast of the U.S., including Alaska and Hawaii, has especially high potential for wave energy development. e East Coast also has opportunities for wave energy and benets from several energetic tidal resources. Regulatory environment Licensing for MHK projects falls under the authority of the Federal Energy Regulatory Commission (FERC). NOAAs Office of Ocean and Coastal Resource Management is responsible for licensing OTEC projects. Licensing and regulation of power genera- tion devices is a fairly broad area of expertise and involves multiple disciplines. Suce it to say that permitting and installing a rst- of-its-kind electricity generator has unique challenges. The emerging MHK industry is reliant on the first developers to push through the licensing process and bring commercial devices online. Like many edgling industries, inno- vation is accomplished in no small part because of the motivation and drive of determined small developers. Industry feedback estimates that it costs between $2-6 million to license a single site. Only upon understanding the potential impacts of electricity generators do you begin to understand the magnitude of the licensing eort. Stakeholders and cooperating agen- cies listed in licensing applications often span several pages. Successful projects have shown that early stakeholder engage- ment is critical for the long-term success of the industry. Most MHK developers in the U.S. are applying for pilot project licenses for their sites. Pilot projects are small, short-term, removable, and carefully-monitored proj- ects intended to test technologies, sites, or both. Specic criteria in the FERC pilot pro- cess include: s P R O J E C T S W I L L B E S M A L L I N C A P A C I T Y E Q U A L T O O R L E S S T H A N - 7 A N D O C C U P Y T H E M I N I M U M A R E A C O M M E N - S U R A T E W I T H T H E T E C H N O L O G Y T O B E E M P L O Y E D s T H E L I C E N S E W I L L B E S H O R T T E R M s P R O J E C T S I T E A V O I D S S E N S I T I V E L O C A T I O N S s P R O J E C T A P P L I C A T I O N S W I L L C O N T A I N S T R I C T S A F E G U A R D P L A N S T O P R O T E C T T H E P U B L I C A N D E N V I R O N M E N T A L R E S O U R C E S Ocean ermal Category Salinity Gradient Category Free Flow Power operating its ?rst full-scale hydrokinetic turbine generator in the Mississippi River, summer 2011. THE EMERGING PLAYER