Water Needs Electricity Needs Water (NYTimes)

May.21, 2009 in Water Industry

(May 21, 2009, The New York Times)

It has long been an axiom of infrastructure planning that it takes a lot of water to make electricity, and a lot of electricity to make water.

Each day, for example, the nation’s thermoelectric power plants (90 percent of all power plants in the United States), draw 136 billion gallons of water from lakes, rivers and oceans to cool the steam used to drive turbines, according to the Department of Energy. In recent years, the energy department says, plans for new power plants had to be scrapped because water-use permits could not be obtained.

For their part, water- and wastewater utilities consume at least 13 percent of the electricity drawn nationwide each day, according to River Network, an environmental group based in Portland, Ore. Such plants face increasing public pressure to cut energy costs and greenhouse gas emissions.

So it was of no small significance that Poseidon Resources last week managed to win approval from California state regulators to build the Western Hemisphere’s largest desalination plant, near San Diego.

Water is an increasingly scarce commodity in the West, so ocean desalination projects are attractive to city and regional planners. But desalination is also inherently energy-intensive, and it will take more electricity to desalinate water at the new facility than to import it from elsewhere, as the utility does now.

Indeed, San Diego Gas & Electric will produce 97,165 metric tons of carbon dioxide annually to supply the Carlsbad desalination plant with the 274,400 MWh of electricity it needs to produce 50 million gallons of drinking water each day for a year.

By comparison, pumping the same volume from the north requires 112,005 MWh; and pumping it from the Colorado River Aqueduct, San Diego’s secondary source of water, requires 167,900 MWh each year, according to the Natural Resources Defense Council.

The San Diego County Water Authority’s options are limited. Statewide drought restrictions and a 2007 federal court ruling forced it to look beyond the northern Sacramento–San Joaquin Delta, from which it now draws three-fourths of its fresh water.

By 2012, the water authority expects less than half of its drinking water to come from the Delta and 10 percent to come from desalinated seawater.

Poseidon also says it plans to spend $55 million improving the plant’s energy efficiency, and it has pledged to use renewable energy sources and voluntarily purchase carbon offsets.

On the East Coast, meanwhile, similar efforts to mitigate the tension between water and power are underway. In February, for example, New York’s Astoria Energy asked Denver-based G.E.A. Power Cooling to design, build and erect an air-cooled condenser for a 575-megawatt natural-gas power plant it expects to bring online in 2011.

The condenser will use no water for the cooling.

And New Jersey’s Atlantic County Utilities Authority (ACUA), which taps wind, biodiesel, solar and landfill gas energy to power its wastewater and trash-recycling operations, says it saved more than $893,000 in electricity costs last year by using renewable sources.

(Original Article Here)