Almost a million huge gleaming, curved mirrors and thermal energy storage covering 3 square miles at the Solana plant are collecting 280 megawatts of concentrated solar power in a unique way.

The world’s largest parabolic trough plant, owned by Abengoa Solar just west of Gila Bend, started producing electricity in October for about 70,000 households in Arizona Public Service Co.’s territory.

While the initial three-year construction phase created more than 2,000 jobs, the $2 billion plant’s daily operations will employ only 117 people by this summer, said Plant Manager Scott Nolan. He added, however, that the plant 70 miles southwest of Phoenix provides more than 3,000 indirect jobs.

The loss of solar jobs following completion of this massive project is one of the reasons for the state’s 13 percent decline in 2013, but a rebound is expected this year, according to the Solar Foundation’s Arizona Solar Jobs Census.

On the other hand, Solana helped keep the state’s solar industry stable by adding 280 megawatts to the state’s total solar installations for 2013, resulting in a net decline of only 2.5 percent from 2012.

Arizona is still the second-largest solar installer in the U.S., but the state’s photovoltaic installations plunged 41 percent last year, largely because many utility-scale power plants had been finished. Utilities have wrapped up enough solar to meet the state’s renewable energy standards for the foreseeable future.

Meanwhile, the U.S. solar industry saw a record-shattering year with 41 percent growth, according to the GTM Research and the Solar Energy Industries Association’s annual report.

• See the upcoming March 14 weekly issue of the Phoenix Business Journal for more on the solar industry in Arizona and the many challenges it faces.

While Solana is a saving grace, it also provides a new type of solar generating technology that likely will be more common in the future as another renewable energy collector.

So how does the Solana plant work? The sun reflects off the curved mirrors, which were made in Surprise (each 20 feet wide, 450 feet long and more than 20 feet tall). This heats an adjoined tube filled with synthetic oil to 740 degrees. The hot oil travels to the nearby power block to create steam, and the steam turbine is driven to create electricity.

“With solar, every day is different,” Nolan said. “The clouds are never the same.”

The mirrors move automatically to track the sun. After sundown or on cloudy days, a thermal energy storage system that includes six sets of hot and cold salt tanks uses stored heat to continue generating electricity for six hours.

All of Solana’s electricity is delivered to Arizona customers through Arizona Public Service Co., which has a 30-year power purchase agreement with Solana. While APS didn’t fund the plant’s construction, it pays monthly for Solana’s electricity. Lockwood would not disclose that dollar amount.

“One of the challenges with (photovoltaic) solar is it drops off before our peak power needs in the summer,” said Barbara Lockwood, APS’ general manager of regulatory affairs and compliance. “Solana is very different. It continues to produce right through the most needed moment of time. It goes onto the system to serve all customers.”

APS worked closely with Abengoa to lobby for an extension of the state investment tax credit to enable the plant to happen. The 30 percent credit made the plant feasible economically, Lockwood said.

“Solana certainly helps us meet our renewable requirements,” she said. “It also allows us to help meet the demand for customers. Not only is it an environmental renewable benefit, but it also helps us meet the demand for our customers. PV provides energy. Solana helps us meet peak demands. It has the economic benefits and has made a distinct difference in the Gila Bend community. It’s just been great for the local economy.”

The plant is projected to provide $300 million to $400 million in tax revenue over 30 years, and it helps curb Arizona’s annual $10 billion energy dollar outflow.

Solana’s environmental benefits are equivalent to removing almost 80,000 cars from the road every year, according to plant officials.

The plant’s water consumption is about one-tenth of the former alfalfa farm’s usage.

Despite the shiny new solar plant, the state’s solar market is floundering. Last year’s net-metering battle between solar installers and APS, the decreased tax incentives and the overall consumer uncertainty regarding all this has challenged the local industry.

Many solar installers and at least one solar activist group are saying it’s APS’ fault.

But APS maintains it is doing what it can to sustain the electrical grid and provide reliable electricity for its customers in the future.

“Generally the overlaying issue is that APS is being portrayed as anti-solar, and that’s the opposite of what our track record portrays,” Lockwood said. “We know that our interests are long term. We’ve got our eye on the long-term solar sustainability and making it long-term for all of our customers.”

John Casey, CEO and owner of Phoenix-based Green Fuel Technologies LLC, said between the utility and political environment, it’s “not a very friendly state to do business in.” He’s had to rely on other contracting jobs for the bulk of his business, with only 20 percent coming from solar jobs.

“Will solar have a market in Arizona?” Casey said. “Yes, in the future — but how long is that future? It depends on the behavior of utilities, rates and how that goes. We will come to a point where it works regardless of political and utility environments. At least, I hope so.”