SunPower Corp. announced on Dec. 15 that it had completed the world’s largest photovoltaic park, the Montalto di Castro park in Lazio, Italy. To finance the project’s construction, it issued investment bonds, which the company said is an industry first.

The recently completed 85 megawatt Montalto project edged out the 80 MW Sarnia, Ontario solar plant, which assumed the title of world’s largest in October 2010.

“On a DC basis, our Montalto di Castro project totals approximately 85 MW and is the largest power plant in the world on an energy production basis in Gigawatt hours per year,” said Natalie Wymer, a SunPower spokesperson. The Sarnia plant will produce roughly 120 Gigawatt hours of electricity annually, while the Montalto project will produce roughly 140 GWh annually.

To finance the project’s construction the company issued 195.2 million euros—$256 million (as of Dec. 21, 2010)—in solar bonds, payable in 2028. A first for the industry.

“As one of the leading solar project developers in the industry due to our experience and bankability, we continue to look for innovative ways to construct and fund our projects,” Wymer said. “Given the significant interest from multiple potential investors for our Montalto project, we saw the opportunity to broaden the investor base to include institutional investors who might not have the ability to invest directly in our projects.”

Looking forward the company will likely use the bond-issuance model to finance future projects.

“The successful closure of the industry’s first investment grade solar bond gives us confidence that we have the ability to utilize this vehicle for future project development,” said Wymer.

The fact that the company was able to finance the project with investment bonds could have a much larger impact on the solar industry.

“It opens up a new global-scale pool of capital to fund solar projects beyond traditional project financing from banks," Dennis Arriola, SunPower CFO, said in a press release.

The project was completed in four phases.

The first 20 MW (alternating current) phase was completed in November 2009. Etrion Corp. purchased the earlier phases of the plant.

The final phases comprised 44 MW (alternating current) and were completed in December.

SunPower said the PV farm already is connected to the local grid, and it is final negotiations for selling the last two phases of the project.

Pictured: SunPower's new Italian plant was able to top Sarnia as the world's biggest solar plant, mostly because it was bigger, but partly due to the pleasantness of its name: "Montalto di Castro" sounds like a nice red wine, while "Sarnia" sounds like a new strain of influenza. Image courtesy of Entrion Corp.