Water Usage in US

Water Usage in US (2)

Types of Available Water

% of Water Types Used for All Sectors

Water Usage by User in US

Water Uses in Energy Production

• Cooling water for steam turbine condenser (largest user)

• Makeup water treatment plant (second largest user; remaining in no particular order)

• Boiler makeup water • NOx control for gas turbines• Auxiliary plant cooling water• Makeup water to flue gas desulphurization• Ash handling and disposal• General domestic use

Water Used for Cooling Purposes

Open Loop System Closed Loop System•H20 withdrawn directly from source

•Lake/river•Heated H20 returned to source

•Thermal pollution•Entrainment problems

•Generally only used at coastal facilities

•Uses tower to transfer heat to ambient air•Withdrawal <5% of open systems

•Overall greater consumption

Types of Cooling Systems

• Once through with cooling ponds/canals• Freshwater once through• Saline once through• Recirculating systems with cooling ponds/canals• Recirculating systems with forced draft cooling towers• Recirculating systems with induced draft cooling towers• Recirculating systems with natural draft cooling towers

(Yang)

Types of Water Used by Thermoelectric Plants

Current Sources• Fresh Groundwater• Surface Freshwater• Surface Saline water• Public Delivery • Sewage• Mixed water sources

(Water Use, Yang)

Cooling Water Sources

rivers

lakesmunicipal

wells

treatment system

cooling pond

sewage reservoir

waste water effluent

Ocean

aquifer mill supply

groundwater

industrial wastewater

Treatment of Water• Impurities present in surface/groundwater sources that must

be addressed• Total dissolved solids

– For many processes, it is unnecessary to reduce except in substantial evaporation losses

• Suspended solids/particulate matter– Treatment depends on level of solids present– Can cause silting/fouling problems in cooling towers/circuits

• Colloidal species– Can’t be removed by ion exchange technology– Must use membrane separation technology

• Dissolved organic matter– Can cause corrosion in turbine cylinders if not treated

Water Treatment for Fossil Fuel Power Generation, Paton

• Research for new sources …• Mine pool water• geological carbon sequestration & coal bed methane

produced water• Industrial/municipal wastewater

• ...and research for water reuse & recovery• reuse power plant cooling water• recover water from plant flue gas

NETL

New Sources

Water Usage in Hydroelectric Power

•Consumptive Uses•Increased sfc. area of reservoir causes faster evaporation

•Non-consumptive Uses

•Water flowing through turbine

•Evaporation = 18gal/kWh consumed by end user

(NREL “Consumptive Water Use for US Power Production”)