On a sun-drenched expanse of former farmland in the Avra Valley area northwest of Tucson, a new project will soon begin harvesting a different kind of crop: energy from the sun.

A roughly 2-square-mile, 25-megawatt photovoltaic array being built by California-based SunEdison at Emigh and Sanders roads is nearing completion.

The project, costing about $100 million of which roughly $30 million will come from federal taxpayers, is expected to begin generating energy for Tucson Electric Power Co. around the end of this month.

It's just one of several utility-scale TEP solar projects expected to come online in the next few months, including an even bigger, 34 MW photovoltaic array just west of the SunEdison project that is slated to go live in November.

The SunEdison photovoltaic project - enabled by a controversial county zoning change - will provide enough power for about 3,500 average TEP homes.

"It's going to be one of our largest sources of renewable power, a really important asset," Joe Salkowski, manager of government relations for TEP, said Wednesday during a tour of the site with local officials.

Under a state mandate, TEP is required to increase the amount of renewable energy it generates to 15 percent of its retail sales by 2025.

TEP now has six utility-scale solar projects in operation totaling 22 MW, with five projects under construction totaling an additional 73 MW, and another 64 MW scheduled to be built by the end of 2013.

Combined with other renewable resources and customer-rooftop solar installations, TEP will have more than 250 MW of renewable energy resources by the end of 2013, producing enough energy to power the equivalent of 50,000 homes, the utility says.

While that sounds like a lot of solar power, Salkowski noted that it's matched by just one project under way for Arizona Public Service Co., which expects its 250-MW Solana concentrating thermal solar plant near Gila Bend to go online next year.

"It's a lot of energy at one site," Salkowksi said. "We find a lot of value in diversity, and in finding different locations for renewable systems around the Tucson area. It gives us some diversity when one array has cloud cover, another might not."

But scattering solar projects around the community also can create some friction, as TEP has discovered.

The SunEdison project - which the California company took over when it acquired the original developer, Fotowatio Renewable Ventures, last year - was held up amid an outcry of opposition from neighbors who contended the solar plant would destroy their rural lifestyle and devalue their homes.

It was finally approved after FRV agreed to mitigating conditions, including the addition of a wall to hide the solar panels from the neighborhood.

SunEdison has tried to alleviate those concerns and work with the neighbors, including generating composite photos showing how the facility will look when viewed from individual homes, said Tim Lasocki, SunEdison managing director for utility development in the West.

A desert-brown-colored concrete-block wall 8 1/2 to 9 1/2 feet tall has been built along the project's expanse along Emigh and Sanders roads, and a short stretch will be built along the north side to shield the facility from the road.

"The idea there was to completely hide the solar panels from the view of the community," Lasocki said, adding that the company recently finished final in-home visual inspections with some neighbors.

The wall does seem to hide most of the project from the road, but not everyone is happy with the result or the project overall.

"I think the project is worthwhile, but the location of the project absolutely stinks," said Rick Westfall, whose home and business property adjoin the solar array. Westfall, who declined to sell his property to SunEdison but has been doing some trucking work for the project, said he is still upset about the political process that led to the zoning change enabling the project to go forward.

Though the wall along Emigh is set back from the road several hundred feet, that doesn't help Westfall, who says he can still see the solar array from his house.

Mike Maier, SunEdison construction manager for the project, said he's spoken with many of the neighbors and believes many of their fears have been allayed, but he acknowledged not all of the neighbors are happy.

To address environmental concerns over the site, which is historic habitat for the western burrowing owl, SunEdison has set aside part of the project as owl habitat, sinking halves of plastic barrels underground to provide ready-made burrows.

SunEdison also has provided $200,000 to Pima County for acquisition of owl habitat elsewhere, Lasocki said, adding that there are plans to introduce burrowing owls to the area.

Despite the neighborhood concerns, TEP and SunEdison officials say the project is good for the local economy.

The exact figure wasn't available, but the project's price tag is in the $100 million range, SunEdison's Lasocki said.

The company plans to take advantage of a 30 percent federal tax credit.

The construction project has employed 250 to 300 employees, and the solar farm is expected to generate $4.5 million in property taxes for Pima County over its 20-year life. The lease revenue will go to Tucson Water, which owns the property. Once in operation, the solar farm will employ one or two full-time managers, Maier said.

TEP declined to say what it will pay for power from the SunEdison array, citing a confidentiality agreement.

Despite steep cost declines for photovoltaics, the technology remains far more expensive than power from coal, which comprises about 80 percent of TEP's power generation, and natural gas.

In a planning document filed with the Arizona Corporation Commission, TEP indicated it expects power from utility-scale, single-axis tracking photovoltaic systems to cost 14.4 cents per kilowatt hour, after factoring in federal subsidies and the intermittent availability of solar power.

By comparison, TEP's retail rates average about 9.5 cents per kilowatt hour.

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In the pipeline

A few of Tucson Electric Power Co.'s solar projects (all photovoltaic) due to come online soon:

• SunEdison-Avra Valley (25 megawatts), online this month.

• NRG Solar-Avra Valley (34 MW); in testing, online by November.

• Astronergy-UA Tech Park (6 MW), by December.

• Prairie Fire-TEP owned near Tech Park (5 MW), by December.

Source: Tucson Electric Power Co.

Contact Assistant Business Editor David Wichner at dwichner@.com or 573-4181.