Systems-level thermodynamic and economic analysis of a seawater reverse osmosis desalination plant integrated with a combined cycle power plant

Abstract

This study includes thermodynamic and economic analyses of a seawater reverse osmosis (RO) plant integrated with a small-scale combined cycle natural gas (CCGT) plant ranging from 36–71 megawatts (MW). These analyses model electricity produced by the CCGT plant as power for the RO plant or for sale to the power grid. These analyses consider the coolant flow rate, carbon intensity, and capital and operating costs of the CCGT plant. For a case where the RO plant is sized according to the rated capacity of the CCGT plant, the maximum flow rate of coolant for the CCGT plant is only 8–10% of the total rate of seawater intake for the RO plant. Thus, no additional intake capacity is needed for the CCGT plant. The carbon intensity of the CCGT plant varies from 802-885 pounds per megawatt-hour (lb/MWh) compared to an average carbon intensity of 1285 lb/MWh for the Texas power grid. The economics of the integrated facility are evaluated using a levelized cost of water (LCOW) framework, which accounts for the capital cost associated with the CCGT plant and electricity sales to the grid. Results indicate that integrating an RO plant with a CCGT plant reduces LCOW by 8–10% compared to an RO plant powered by electricity from the Texas power grid. Citation: Reimers AS, Webber ME. 2018. Systems-level thermodynamic and economic analysis of a seawater reverse osmosis desalination plant integrated with a combined cycle power plant. Texas Water Journal. 9(1):82-95. Available from: https://doi.org/10.21423/twj.v9i1.7065.