Four out of five Arizonans use water delivered to them across the state through the pumps, canals and reservoirs of the Central Arizona Project. In recent years, the CAP has found a more economical and environmentally friendly way to deliver these critical water supplies.
The agency had acquired all its power from the coal-fired Navajo Generating Station in northern Arizona - but when the plant was decommissioned in 2019, it was forced to look elsewhere.
CAP's Assistant General Manager for Operations and Engineering, Darrin Francom, said the new distribution plan draws power from a variety of sources.
"On average, we take just a little over 1.4 million acre-feet of water, and through the entire system, the water is lifted about 2,800 feet," said Francom. "So, that's a tremendous amount of energy to lift that volume and that weight of water."
Francom said CAP is the largest single user of electricity in Arizona, consuming 2.5 million megawatt-hours of power to distribute Lower Colorado River Basin water over 360 miles of canals and tunnels.
He said the new power system saves millions of dollars a year.
According to Francom, the efficiency in the system comes through determining the best times to pump the water.
"We minimize our pumping during the summer months, when we have the highest energy prices," said Francom. "Because we can move most of our water at the start and the end of the year. In the summertime, we can reduce our pumping and make deliveries to our customers."
Francom said most of their power is now purchased annually through what he calls "reverse e-Bay auctions," where power wholesalers try to underbid each other for long-term contracts. He says CAP saves even more, through finding short-term "bargains" on the spot market.
"We acquire somewhere in the neighborhood of 80% of our energy, and then we have 20% that we kind of withhold for day-ahead energy purchases," said Francom. "And that allows us to match exactly our energy that we have to the pumping that we need."
The Colorado River Basin Project Act was created in 1968 by federal legislation. The agency that became the Central Arizona Project was created in 1971, to repay the federal government for the costs of construction and to manage and operate the system.