But they do. So do coal and water, and ethanol and water.

There's a connection between water and energy that many water planners don't appreciate, said Melinda Kassen with Trout Unlimited.

"It goes both ways. There's water needed to produce energy. But there's energy needed to develop and deliver water," said Kassen, who sits on a high-level water panel called the Interbasin Compact Committee. "If you talk about this, I think, you need to talk about both sides."

Coal power plants need water to generate steam for their turbines and to cool off excess heat in their towers. Ethanol requires water for irrigation and to process corn into a useable fuel. Oil shale needs water to scour the underground rocks and refine the product into fuel for vehicles and jets.

Fast-growing Phoenix will build five more power plants, Kassen said, yet none of the water demand estimates she's seen for the Western United States take the increased demand for power into account.

By 2030, U.S. power plants could be using as much water as all domestic users in the country were in 1995, according to a Department of Energy report called "Energy Demands on Water Resources."

Closer to home, water planners are keeping their eyes on the large conditional water rights of Shell and Chevron, but the largest conditional water right in Colorado is for a future power plant. The Colorado River Water Conservation District owns the right to store more than 1 million acre-feet of water a year in Juniper Reservoir. Like the oil companies' reservoirs, Juniper does not exist yet.

The Eastern Plains are producing energy, too, thanks to the ethanol boom. But today's ethanol plants use corn, and Colorado corn usually requires irrigation.

Ethanol made from irrigated corn takes about 1,400 gallons of water per one gallon of ethanol produced, according to the Department of Energy's report.

However, a lot of the acres used for ethanol are already under cultivation, and some of the water used for irrigation seeps into the ground and eventually migrates back into the river for use downstream.

It takes energy to move water, too, Kassen said. Farmers and suburbs need power to run their well pumps.

Fort Collins entrepreneur Aaron Million has plans for a 400-mile pipeline from Southwest Wyoming to the Front Range. It will require lots of energy to run the pumps, Kassen said. Million, though, said he's looking at using wind turbines and solar cells. And because the pipeline loses elevation on its way into Colorado, he can use it for hydroelectric power.

Originally, he estimated the yearly operation costs would be $50 million to $75 million, but that cost will drop if the project uses renewable energy, Million told state legislators in September.

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