A photovoltaic solar plant to be built at Tucson Water's Clearwater Recharge and Recovery facility in Avra Valley would produce approximately 5 percent of the electricity used by the facility.
Electricity from the 1-megawatt direct current project will be used to operate pumps and motors that move water from the Central Arizona Project into the Tucson Water recharge and storage system, generating enough energy to produce about 6.5 million gallons of water yearly.
Fernando Molina, water conservation manager and interim public information officer for Tucson Water, said the project is scheduled to begin in October, as long as all the necessary agreements are in place.
"This project involves agreements with energy utilities that we need to finalize," Molina pointed out. "Tucson Water will purchase power from the developer of the project, but Trico Electric Cooperative is the energy service provider out there (in Avra Valley) and we have to work out an agreement with them."
Molina added that Tucson Water already has an agreement in place with Tucson Electric Power regarding the proposed plant.
Sun Power Corp. of San Jose, Calif., was the successful bidder to construct the plant. Molina said 15 companies participated in the pre-bidding process, and seven submitted proposals. Tucson Water will have a 20-year contract with Sun Power at the cost of .159 dollars per kilowatt hour, he noted.
The plant will consist of 2,500 photovoltaic modules capable of generating one megawatt of direct current electricity. The PV units, which have 275 trackers to follow the sun, will sit on a 10-acre parcel.
"Our savings will come from the cost of lowering demand for electricity, particularly during the peak use hours," Molina pointed out. "We'll lower our demand for electricity off the grid, and while we'll pay about the same for the energy, our savings will come from having to purchase less of it."
Molina said Tucson Water would receive renewable energy credits, which it will sell to Trico, which then gets credit from the Arizona Corporation Commission toward Trico's 2025 renewable energy goal of generating at least 15 percent of its power from renewable energy sources.
Molina added the project is being built with the help of federal clean renewable energy bonds.
"This is the first project of this type that we've been involved in," Molina said. "About half of our water supply comes out of that facility, where we also have well fields, pumps, reservoirs and a booster station that pushes water over to the Hayden Udall plant that treats and disinfects the water. So there's a lot of equipment that uses electricity out there."
Advantages to producing solar electricity at the plant, according to Molina, include using a renewable fuel source (the sun) to help power equipment, reducing Tucson Water's carbon footprint, and using locally-produced power that doesn't have transmission losses that come with purchasing power from somewhere else.