Renewable Ocean Thermal Energy for Low-Pressure Desalination of Seawater with Co-Production of Ammonia

Statement of Problem and Opportunity: The proposed SBIR project addresses the both the threat and opportunity that global oceans present in the foreseeable future. The global scarcity of fresh water is well documented as the world’s population rises and increasing demand by alternate energy sources. We now have a Window of Opportunity to develop renewable Ocean Thermal Energy as baseload Marine Energy for coproduction of power, desalinated water and ammonia as hydrogen carrier. Tropical oceans capture and stores the solar energy that can be harnessed as the role of renewable energy increase during the transition period between 2020 and 2050 (U.S. EIA Report, 2020) for achieving decarbonization goal of 2050. Ocean Thermal Energy can play a key role for achieving 2050 decarbonization target. Integration of OTEC with the EcoVillage planned for the island of St. Croix, USVI directly address Subtopic 18d. Successful deployment of an integrated OTEC-EcoVillage will be a showcase for the island states. Technical Objectives: The governing objective of this SBIR Phase I application is the development and design of prototype Ocean Thermal Energy system for coproduction of power, desalinated water and carbon-free ammonia for the end user EcoVillage on the island of St Croix, USVI with Ocean Thermal Energy (OTE) Corporation as end-user partner. OTE has developed a business plan for the development of EcoVillage and Ocean Thermal Energy will provide power and desalinated water for making EcoVillage a true carbon-free community. Therefore, the proposed project is directly relevant to the Subtopic 18d. Technical Approach: The OTEC technology developed in the past focused on power generation using closed cycle using ammonia as working fluid. In an alternate open cycle system, warm water is flash evaporated to run low-pressure steam turbine followed by condensation using the deep-ocean cold water. The proposed SBIR project will further develop Hybrid OTEC cycle by integration of close and open cycle systems for coproduction of desalinated water and power that is used to generate hydrogen for production of ammonia. The expected outcomes of the Phase I project are a) design of prototype Hybrid-OTEC system and b) TEA to demonstrate the techno-economic merits of a carbon-free OTEC-EcoVillage and c) Phase II plan for advancing the technology from TRL5- to TRL-6 of Prototype System Verified in Operational Environment. Commercial Applications and Other Benefits: The technical, economic and social benefits of the Ocean Thermal Energy are well recognized with the statement of Time Has Come for OTEC based on the foundation of technology developed by federal and private investments over the last 40 years. The U.S. EIA Report clearly defines the need for sustainable renewable energy during the transition period between 2020 and 2050. Need for desalination of seawater and ammonia as hydrogen carrier are well recognized as demonstrated by global R&D and Demonstration. U.S. must maintain the lead on the Ocean Thermal Energy and EcoVillage for securing domestic job creation.