The City of Tucson is about to realize its dream of installing a solar array on a large chunk of retired agricultural land owned by Tucson water.

The city has started construction on a 1-megawatt ground-mounted tracker solar photovoltaic system by SunPower that’s expected to be finished by March of 2011.

Tucson Water, the publicly owned water utility, bought a huge swath of retired agriculture land, mostly for the water rights, some years ago, said Asia Philben, a hydrologist with Tucson Water.

Many in the city have long looked to the site as a potential home for a major solar project.

“It was previously agricultural land,” Philben said, “so it’s not pristine, and it’s flat.”

Those factors make the area a prime candidate for solar development. The city conducted a feasibility study to see if the dream of covering the whole area in photovoltaic panels to produce power, for the water facility as well as the city, could be realized.

“While that’s not really feasible,” Philben said, “I do think we see this as a stepping stone to what could become a bigger project.”

The 1-megawatt SunPower system will only provide about 5 percent of the facility’s power, Philben said, because it does pump water from the Colorado River on the other side of the Tucson Mountains 24 hours a day, seven days a week.

The energy need there is significant. And the facility doesn’t pay a lot for the power it uses, which has been a hindrance in installing a solar project there, Philben said.

SunPower will own, operate and maintain the system, while selling the power to the city utility company. Trico Electric is helping to finance the project by agreeing to buy the clean power credits, according to a press release on the project.

Solar photovoltaic power makes sense in Tucson and especially at the water facility, Philben said.

“We recognize that photovoltaic has low water use,” she said. “And we are in the desert here.”

Construction has started on the 10-acre site and is expected to continue through the winter, according to the release.

“We are really excited to be able to do it,” Philben said.

Image courtesy of SunPower.