Dry and hybrid cooling FOR Power Plants

Since a significant quantity of heat must be removed in order to condense the steam used to power turbine generators, cooling systems are typically a power plant's primary supply of water. Previously, this cooling was provided by bodies of water like rivers and lakes, but in recent years, the number of power plants using dry cooling has increased (a cooling system that uses little to no water). Dry cooling systems are more expensive to install and use more energy to run. The overall reduced efficiency of power plants is a result of these variables, yet dry cooling systems consume 95% less water than wet cooling systems.

In a variety of power plants, steam is produced by boiling water, which is then passed through turbines to produce electricity. This kind of system is used in nuclear power plants, plants that burn coal and biomass, some natural gas plants, and even some solar facilities. The steam from these plants must be cooled so that it may condense back into liquid, after which it must be sent back to the boiler or steam generator.

Water is typically used in steam power plants to cool and condense the steam. The majority of the water withdrawn in the US is used for cooling, however the US Geological Survey estimates that power generation accounts for around 40% of all water withdrawals.

Recirculating cooling systems that recirculate cooling water are used by more than 61% of thermoelectric generating capacity in the US. To allow for reuse, these systems keep the water in closed-loop pipelines. 36% of the US thermoelectric capacity is accounted for by power plants using DC cooling systems. Large amounts of water are drawn by these systems from adjacent bodies of water to cool the condenser, and the warmed water is subsequently returned to the original source.

3% of US cogeneration capacity is made up of dry and hybrid cooling, the majority of which has been operational since 2000. Steam is cooled and condensed using ambient air in dry cooling systems. Direct systems and indirect systems are the two types of these systems. Although ambient air is used to condense steam in direct dry cooling systems, no water is used in the process. In indirect dry cooling systems, the cooling water stays in the closed system while the steam is condensed in a typical water-cooled condenser. As a result, no water evaporates and as a result, very little water is consumed.

Hybrid cooling systems combine dry and wet cooling and have the ability to condense steam using both water and air. Typically, these systems are made to function as dry cooling systems in cooler months and as wet cooling systems in warmer months when dry systems are less effective.

In the US, there are 83 facilities using hybrid and dry cooling systems to support a total steam generation capacity of about 20 GW. Although Texas has the biggest dry cooling capacity (2.8 GW), Virginia is closely behind Texas with the most dry cooling systems (13) in California (2.4 GW).

Natural gas combined cycle (NGCC), which accounts for more than 83% of dry and hybrid cooling operating capacity, is the most widely used generation technology. Natural gas combined cycle plants typically require far less cooling per MWh than coal or nuclear reactors, making dry cooling systems more cost-effective. In the US, dry cooling technology is used in more than 15% of natural gas combined cycle plants' operating production capacity.

Another appealing choice for concentrating solar power systems is dry cooling. Many modern concentrating solar power systems use dry cooling because they are situated in regions like the Southwest of the United States where solar resources are relatively abundant and water resources are relatively scarce.