By Neil Strother

Pike Research

The testing of the cooling technology is taking place at the Water Research Center (WRC) at Georgia Power’s Plant Bowen, near Cartersville, Ga.  A team of researchers from 13 companies will test the technology, which is aimed at reducing power-plant water withdrawals and improving the quality of water related to power generation.

The scale of the problem deserves attention.  The U.S.’s thermoelectric power plants supply some 91% of the electricity in the country.  They operate by using heat (from a variety of possible sources including coal, natural gas, nuclear, oil, biomass, geothermal or concentrated solar) to create steam, which drives a turbine generator that must be cooled to condense the steam at the turbine exhaust.  It takes lots of water for that cooling process, amounting to 41% of all freshwater withdrawals and about 3% of freshwater consumption.

According to a Sandia Labs report from 2006, thermoelectric power generation consumes 3.3 billion gallons of water per day in total, or roughly 3.3% of total U.S. water consumption.  But when agricultural consumption of freshwater is removed from the equation, the thermoelectric plants use nearly 20% of non-agricultural consumption.  The Sandia report points out that “based on current water markets and values, the growth in energy demand, along with stricter environmental regulations on cooling and water withdrawals, could double water consumption for electric power generation [emphasis mine] over the next 25 years, consuming as much additional water per day as 50 million more people or more.”

So the need is great for plant operators to reduce water use, which is where the new research center in Georgia comes into focus. The researchers there will test a “thermosyphon cooler” developed by Johnson Controls.  This new process uses an air-cooled refrigerant to pre-cool water before it enters a cooling tower, thereby cutting water consumption.

The testing is expected to last a year as researchers document the water savings potential. No one has said publicly what to expect in terms of savings, but even an incremental reduction spread across multiple power plants could have a significant impact if the technology proves viable.  As Tom Alley, vice president of generation for the Electric Power Research Institute (EPRI) and one of the center’s participating companies, says, “Current events of drought and high demands on existing water supplies emphasize the importance of water management.”