Potential Installation of Ocean Thermal Energy Conversion Systems with Combined Use of Deep Sea Water

Abstract

The present study assesses life cycle CO₂ (LCCO₂) reduction costs of ocean thermal energy conversion (OTEC) systems with combined use of deep sea water by area considering the natural and social conditions in different areas of Japan. This study considers sea surface temperature, climate, region scale, type of grid power and location as regional conditions. The assessment reveals that the LCCO₂ reduction cost greatly varies from 860 to 323,000 [JPY/t-CO₂] depending on the areas. Areas where LCCO₂ reduction costs are less than 30,000 [JPY/t-CO₂] are the medium and large scale remote islands of Okinawa, the Okinawa main island, the largescale remote islands of Kyushu, and the large-scale remote islands of Shikoku, where the installation of OTEC systems are promising. There are the two main reasons for the small LCCO₂ reduction costs in these areas; first, the amount of power generation is large because of the low latitude. Second, the effect of combined use of deep sea water is large because these areas have large cooling demand due to the low latitude or the large regional scale.