Economic Analysis for an Integrated OTEC/Biomass System

抄録

In this Paper, an integrated OTEC/biomass system is proposed. This system consists of OTEC with optional 2nd stage desalination, deep water air conditioning, giant kelp cultivation utilizing nutrient-rich deep water, and marine biomass conversion (methane production by anaerobic digestion and gas turbine power generation). In order to determine the cost effectiveness of the integrated OTEC/biomass system, economic analysis was performed using input parameters taken from the literature. The results of an sensitivity alalysis show that the addition of a 2nd stage desalination system becomes cost effective only when the market value of fresh water is $0.9/m^3 or greater, and that the air conditioning co-product influences the overall cost only for small OTEC systems (< 10MW). The cost of electricity depends on the scale of the biomass conversion system, and this dependency is affected by the discount rate. In addition, we investigated the optimum distribution of electric power production between the OTEC and biomass conversion systems. When the total power production is small (< 10MW), the optimum distribution ratio is 100% OTEC for low discount rates (< 8%), and l00% biomass conversion for high discount rate (> 10%). For total electric power production of > 50MW, 68% OTEC and 32% biomass conversion becomes the optimum distribution ratio in some cases. When the discount rate is low (< 8%), the optimum system is competitive with fossil fuel power systems.