The 21st century is characterized as an era of natural resource depletion, and humanity is faced with several threats due to the lack of food, energy, and water. Climate change and sea-level rise are at unprecedented levels, being phenomena that make predicting the future of ocean resources more complicated. Oceans contain a limitless amount of water with small (but finite) temperature differences from their surfaces to their floors. To advance the utilization of ocean resources, this book readdresses the past achievements, present developments, and future progress of ocean thermal energy, from basic sciences to sociology and cultural aspects.

Increasing renewable energy development, both within the United States and abroad, has rekindled interest in the potential for marine and hydrokinetic (MHK) resources to contribute to electricity generation. These resources derive from ocean tides, waves, and currents; temperature gradients in the ocean; and free-flowing rivers and streams. One measure of the interest in the possible use of these resources for electricity generation is the increasing number of permits that have been filed with the Federal Energy Regulatory Commission (FERC). As of December 2012, FERC had issued 4 licenses and 84 preliminary permits, up from virtually zero a decade ago. However, most of these permits are for developments along the Mississippi River, and the actual benefit realized from all MHK resources is extremely small. The first U.S. commercial gridconnected project, a tidal project in Maine with a capacity of less than 1 megawatt (MW), is currently delivering a fraction of that power to the grid and is due to be fully installed in 2013. As part of its assessment of MHK resources, DOE asked the National Research Council (NRC) to provide detailed evaluations. In response, the NRC formed the Committee on Marine Hydrokinetic Energy Technology Assessment. As directed in its statement of task (SOT), the committee first developed an interim report, released in June 2011, which focused on the wave and tidal resource assessments (Appendix B). The current report contains the committee's evaluation of all five of the DOE resource categories as well as the committee's comments on the overall MHK resource assessment process. This summary focuses on the committee's overarching findings and conclusions regarding a conceptual framework for developing the resource assessments, the aggregation of results into a single number, and the consistency across and coordination between the individual resource assessments. Critiques of the individual resource assessment, further discussion of the practical MHK resource base, and overarching conclusions and recommendations are explained in An Evaluation of the U.S. Department of Energy's Marine and Hydrokinetic Resource Assessment.

This timely volume provides a comprehensive review of current technology for all ocean energies. It opens with an analysis of ocean thermal energy conversion (OTEC), with and without the use of an intermediate fluid. The historical and economic background is reviewed, and the geographical areas in which this energy could be utilized are pinpointed. The production of hydrogen as a side product, and environmental consequences of OTEC plants are looked at. The competitiveness of OTEC with conventional sources of energy is analysed. Optimisation, current research and development potential are also examined.Separate chapters provide a detailed examination of other ocean energy sources. The possible harnessing of solar ponds, ocean currents, and power derived from salinity differences is considered. There is a fascinating study of marine winds, and the question of using the ocean tides as a source of energy is examined, focussing on a number of tidal power plant projects, including data gathered from China, Australia, Great Britain, Korea and the USSR.Wave energy extraction has excited recent interest and activity, with a number of experimental pilot plants being built in northern Europe. This topic is discussed at length in view of its greater chance of implementation. Finally, geothermal and biomass energy are considered, and an assessment of their future is given.Each chapter contains bibliographic references. The author has also distinguished between energy schemes which might be valuable in less-industrialized regions of the world, but uneconomical in the developed countries. A large number of illustrations support the text.Every effort has been made to ensure that the book is readable and accessible for the specialist as well as the non-expert. It will be of particular interest to energy economists, engineers, geologists and oceanographers, and to environmentalists and environmental engineers.

The United States and China are the world's top two energy consumers and, as of 2010, the two largest economies. Consequently, they have a decisive role to play in the world's clean energy future. Both countries are also motivated by related goals, namely diversified energy portfolios, job creation, energy security, and pollution reduction, making renewable energy development an important strategy with wide-ranging implications. Given the size of their energy markets, any substantial progress the two countries make in advancing use of renewable energy will provide global benefits, in terms of enhanced technological understanding, reduced costs through expanded deployment, and reduced greenhouse gas (GHG) emissions relative to conventional generation from fossil fuels. Within this context, the U.S. National Academies, in collaboration with the Chinese Academy of Sciences (CAS) and Chinese Academy of Engineering (CAE), reviewed renewable energy development and deployment in the two countries, to highlight prospects for collaboration across the research to deployment chain and to suggest strategies which would promote more rapid and economical attainment of renewable energy goals. Main findings and concerning renewable resource assessments, technology development, environmental impacts, market infrastructure, among others, are presented. Specific recommendations have been limited to those judged to be most likely to accelerate the pace of deployment, increase cost-competitiveness, or shape the future market for renewable energy. The recommendations presented here are also pragmatic and achievable.

Fundamentals of Ocean Renewable Energy: Generating Electricity from the Sea presents the basic concepts of mechanics and introduces the various technical aspects of ocean renewable energy. Contents follow a logical sequence, starting with hydrodynamics and then separately examining each conversion technology, with special focus on tidal energy, offshore wind and wave energy, as well as current and ocean thermal energy conversion (OTEC). The authors explore key topics for resource characterization and optimization, such as monitoring and measurement methods and ocean modeling. They also discuss the sustainability, planning, integration and distribution challenges for the implementation of these technologies, including co-location with other systems. Finally, case studies of ocean energy sites and devices allow for a better understanding of how ocean energy conversion works in real-world settings. This book is an invaluable resource for students at graduate and senior undergraduate level engineering (ocean, mechanical, and civil) and oceanography with prior knowledge of fluid mechanics and mechanics of materials. - Presents the fundamental physics and theory behind ocean energy systems, covering both oceanographic and engineering aspects of ocean energy - Explores the most widely adopted conversion technologies, including tidal, wave, offshore wind, ocean thermal and currents