18-11: Cost/Performance Tradeoffs Among Wet, Dry and Hybrid Cooling Systems

The needs for increasing amounts of electric power and to conserve locally limited fresh water supply can sometimes come into conflict. Since power plant cooling is the major use of water in most plants, it is the choice of cooling system that frequently mediates this conflict. Traditional wet-cooling systems have good efficiency and low cost but high-water consumption; dry cooling virtually eliminates water consumption but at higher cost and reduced efficiency. Hybrid, wet/dry cooling systems enable significant water savings, albeit at higher cost, in comparison to wet cooling and provide improved plant efficiency and output at frequently lower cost in comparison to all-dry systems. This paper presents quantified tradeoffs among wet, dry and hybrid cooling systems for typical gas-fired, combined-cycle plants operating in a range of ambient conditions characteristic of the State of California in the US.