Water and Energy -the Two for One Bargain

“By one action they can help save two resources, I think they will like that. I think they’ll get it,” said Ronnie Cohen, a senior policy analyst for the Natural Resources Defense Council, an environmental advocacy group.

. “It’s a two-for-one … and everybody loves a bargain.”php493b72415108b

Generating electricity accounts for almost half the nation’s annual water use – and water systems use energy to treat and distribute supplies.
Usually more electricity is needed to supply water than it takes water to generate electricity, especially in the arid  Western US.

In non-hydroelectric plants water mainly is used to cool the system’s equipment or produce steam to turn turbines. Power plants with the biggest water demands often return the water to its source – a lake or river – with only some losses, mostly to evaporation.

In Arizona, where power plants lack direct water sources, closed cooling systems recycle the water multiple times. The overall demand is lower, but no one has yet to design a recycling system that would return the used water to its source.

Water needs electricity to pump it, move it, treat it, distribute it, retrieve it then after it’s used and it needs an efficient healthy way to recycle it.

The 336-mile Central Arizona Project canal moves water from the Colorado River through Phoenix, Pinal County and south to Tucson. A series of 15 pumping stations lifts the water a total of nearly 3,000 stair-stepping feet in elevation.

How much energy does it take to move water -Can you design a more cost effective green healthy system?

  • It takes more than half a power plant just to operate.
  • Moving one acre-foot of water from the river to the city it serves, enough to supply one or two households for a year, consumes an average of 1.7 megawatt-hours of electricity, enough to light one of those households for about six weeks.
  • To draw that much electricity from the grid, the CAP buys blocks of power from the Navajo Generating Station in Page, a coal-fired plant that draws water for its cooling process from the Colorado River at Lake Powell.
  • Coal fire pollutes the air and the coal is usually mind in a destructive manner.
  • Curbing greenhouse-gas pollution needs to be done in a cost effective way.

How can we recycle water effeciently and greener?

  • Paying farmers to leave fields unplanted or
  • Desalting groundwater now considered too full of minerals and contaminants to use. More water would add to power demands.
  • Seek new power sources or invest in water resources closer to home- desalinating mineral- laden groundwater or learning how to create water from other sources yet tapped.

“To add water, we will need additional energy,” McCann said. “More power generation will mean more water. . . . It’s that circle.”

Creating sustainability -the challenges

  • Desalting brackish groundwater, for example, uses nearly twice the power as moving it from the river
  • Desalting ocean water would require more than three times the energy.
  • Added production costs mean higher consumer costs.
  • Power providers use recycled water  in producing electricity, but must learn to use less water to produce more eneergy. Redhawk Power Station runs on natural gas, recycles its cooling water through as many as 23 cycles, a process that uses cutting-edge technology.
  • Hydroelectric powe rat Shoshone Power Plant in Colorado operates by drawing “excess” water downstream before upstream communities can use it. That has to be rethought. The water returns to the river but  the communities have no way of capturing it before it enters Utah.
  • By  purchasing consumers will need to install high-efficiency washing machines and dishwashers, which can use 35 to 50 percent less water and 50 percent less electricity.

Such efforts need to infiltrate all levels of both energy and water providers to ensure long-term sustainability, advocates say, but like many sustainable efforts, the best successes may begin with those light bulbs and front-load washing machines.

“If you can tell people that by one action they can help save two resources, I think they will like that. I think they’ll get it,” said Cohen of the Natural Resources Defense Council. “It’s a two-for-one … and everybody loves a bargain.”

Excerpts and image courtesy of  AZ. Republic
Arizona’s water and power supplies intertwined
– Shaun McKinnon – Dec. 7, 2008
The Arizona Republic as reported in
http://www.azcentral.com/news/green/articles/2008/12/07/20081207sustain-watergy1207.html

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