This paper presents a brief review of recent researches on deep ocean water applications in Japan. Firstly, various applications using deep ocean water, such as ocean thermal energy conversion, fresh water production, air conditioning/refrigeration, mariculture, agriculture, are summarized. Then, major deep ocean water facilities in Japan are introduced. Finally, two national projects, which are driven by Japan Ocean Industries Association (JOIA) and Marino-Forum 21 (MF21), are briefly presented.
World population has rapidly increased since the industrial revolution. At this rate, population will become 10 billion by the end of the first quarter of this century, meaning severe consequences for future energy and food securities. Improvement of the living standard in developing nations raises energy demand worldwide. However, increase of conventional power plant based on fossil fuels will make worse of global environment represented by global warming and acid rain. Therefore the world's energy economy is beginning to move away from fossil fuels toward renewable energies, such as solar, wind, geothermal, biomass and several ocean energies. Strengthening the international regulation for CO2 emission rate would accelerate this trend. World's crop yields have drastically increased in recent years, but the growth saturated at around 10 years ago due to the limit of terrestrial soil capacity. The total fisheries catch in the world reaches 100 million tons in 1989 and has stagnated since then, because many fishing areas and species have reached their maximum sustainable yields. This means that any new technologies for sustainable primary production are required. Deep ocean water (DOW) is cold, nutrient-rich and pathogen-free seawater found at depth of several-hundred meters or lower. The DOW has attracted special interest as a renewable resource for energy and marine primary production, and also been focused as the useful material for fresh water production, air conditioning/refrigeration, and so forth.