InforSim- Ocean Thermal Energy


	InforSim was involved in the early work on Ocean Thermal Energy Conversion (OTEC) technology in response to the oil crisis during the 1980's. We were contracted to perform system engineering studies for a 40 MWe OTEC plant at Kahe Point, Oahu, Hawaii being developed by Basic Resources Corporation and TRW Systems (see illustration). This work proceeded through the preliminary design stage and included the following activities:
	• baseline environmental surveys at the proposed plant site • design of the power plant and cold water pipe • thermal Rankine cycle analyses • estimation of capital and operational costs In support of these activities, the OTEC Design Optimization and Performance (ODOP) Model was developed with the objective of maximizing return on investment. The model was used to design an “optimal” OTEC plant configuration for site-specific environmental conditions at the Kahe Point site, including plant scale, offshore containment structure location, cold water pipe size and routing, and heat exchanger configuration. Another major area of our involvement with the 40 MWe OTEC plant at Kahe Point was to serve as the environmental coordinator. Our company performed a number of tasks in this role, including: • producing an Environmental Assessment and related environmental impact documents • modeling and analyzing potential plankton blooms downstream from the nutrient-rich OTEC discharge • modeling and analyzing potential impacts to reef fish, coastal pelagic fish, and bottom fish found in the vicinity of the nearshore OTEC plant
	For the latter study, a special fish population dynamics model was developed to estimate the composite effects of entrainment of fish eggs/larvae, impingement of juvenile fish, fish attraction to OTEC structures, increased fishing activity near the OTEC site, and increased predator concentrations. The OTEC impacts were formulated as perturbations to natural life stage processes and nonlinear programming techniques were incorporated to treat uncertainty in model parameters values. The computational results provided not only estimates of the potential minimum and maximum impacts, but also the sensitivity of the results to the estimated model parameter values via Lagrange multipliers. In a review of the environmental modeling studies of the Kahe Point OTEC Plant by NOAA¹, the InforSim models were particularly recognized. "Of all the models, (InforSim's) treatment of the plankton ecosystem appears most reliable". Relative to our fish impact model, it was stated that: "This is the most valuable of all of the OTEC models in that it provides insight into major gaps in our knowledge which need to be filled." We believe that our modeling advancements since these developments will provide even better capabilities for analyzing environmental impacts of future OTEC concepts. (1) Harrison. J.T. 1987. The 40 MWe OTEC Plant at Kahe Point, Oahu, Hawaii: A case study of potential biological impacts. NOAA-TM-NMFS-SWFC-68. U.S. Department of Commerce, National Marine Fisheries Service.