The Italian Montalto di Castro and Rovigo PV plants

On November 23rd, 2010 Developer SunEdison LLC (Beltsville, Maryland, U.S.) announced the commissioning of an enormous solar photovoltaic (PV) plant on a site where an industrial park meets farmland, near the town of Rovigo in the Veneto region of Northeastern Italy. Composed of 280,000 polycrystalline PV modules, the Rovigo plant has an output of 70MW-DC, making it one of the largest PV plants in the world.

: The Montalto Di Castro plant boasts an output of 84.2MW-DC (72MW-AC). Courtesy: SunPower Corp.

Less than a month later on December 15th 2010, SunPower Corporation (San Jose, California, U.S.) announced the commissioning of 44MW in the third and fourth phases of an even larger PV plant in grazing lands near the Meditteranean in Central Italy. In total, the Montalto Di Castro plant boasts an output of 84.2MW-DC (72MW-AC), making it the largest PV plant in Europe.

As a result of these auspicious developments, Solar Server's March 2011 Solar Energy System of the Month column features the large-scale PV plants at Montalto di Castro and Rovigo, which serve as beacons to the future of European energy production and show that in the move to a low-carbon economy, dramatic things can happen in short periods of time.

Italian sunshine, rapid market growth

: Italian solar irradiation. Courtesy: JRC

It is appropriate that these landmark PV plants are located in Italy, a nation that has catapulted to a position as a competing PV market to Germany in 2010, with 3.77GW of PV (including partially completed PV systems) applying to participate in the nation's feed-in tariff.

The Italian market for large-scale PV systems with a capacity of 200 kW or more saw the fastest growth worldwide, tripling in only one year.

Following Germany and Spain, Italy became the third country with a cumulated installed capacity over 1 GW in 2010. As a result of the market's rapid development Italy entered the Top5 ranking of the world's largest PV plants with the solar parks Rovigo (70 MW) and Montalto di Castro (Lazio, 84 MW), and the Top 10 including a 34.6 MW plant in Sant'Alberto, Emilia-Romagna.

The world's largest PV plants

Power DC (MWp)	Country	Location	Region	On grid
97	Canada	Sarnia	Ontario	2010
84,2	Italy	Montalto di Castro	Lazio	2010
80,2	Germany	Finsterwalde	Brandenburg	2010
70,6	Italy	San Bellino	Veneto	2010
60	Spain	Olmedilla de Alarcón	Castilla-La Mancha	2008
54	Germany	Straßkirchen	Bayern	2009
52,8	Germany	Lieberose	Brandenburg	2009
48	USA	Boulder City, NV	Nevada	2010
47,6	Spain	Puertollano	Castilla-La Mancha	2008
46	Portugal	Amaraleja	Alentejo	2008
42,7	Italy	Cellino San Marco	Apulien	2010
40	Germany	Brandis	Saxonia	2008
36	Germany	Reckahn	Brandenburg	2010
35	Czech Republic	Vepřek	Středočeský kraj	2010
34,6	Italy	Sant'Alberto	Emilia-Romagna	2010

SunRay and Montalto di Castro: ambitious beginnings

Developer SunRay Renewable Energy Ltd. (Floriana, Malta) began construction of the Montalto Di Castro plant in February 2009. Even then the goals for the plant were ambitious; as SunRay began work on the 25MW-DC plant, the company planned an expansion to 100MW by the end of 2010.

: construction of the Montalto Di Castro plant started in February 2009. Courtesy: SunPower Corp.

In October 2009, SunRay acquired EUR 120 million (USD 166 million) in financing for the project, through Banca Infrastrutture Innovazione e Sviluppo, Société Générale and WestLB AG. On December 16th 2009 SunRay completed the first 25MW-DC (20MW-AC) phase of the PV plant, already one of the largest in the continent.

SunPower purchases Montalto di Castro

SunRay had partnered with SunPower Corporation for engineering, procurement and construction services, as well as to supply the modules and trackers for the plant. The Montalto di Castro plant uses SunPower E19 modules mounted on SunPower T0 tracking systems, which SunPower says produce up to 25% more energy than fixed-tilt systems.

However, SunPower was to have a greater role than supplying these services and components, and in the Spring of 2010 acquired SunRay and its 70 employees, finalizing the acquisition of the company on March 29th, 2010.

Montalto di Castro was one of a number of PV projects inherited through this transaction, and in the summer and fall of 2010 SunPower expanded the plant, adding another 8MW-AC which was commissioned in the Fall of 2010.

"Solar bonds" and the sale of Montalto di Castro

For the final phases of the plant, SunPower developed a novel financing tool, which it describes as the industry's first "solar bond". The lead managers for the bonds were BNP Paribas and Société Générale, and through the bond SunPower acquired EUR 195 million (USD 269 million) to complete the plant.

: Tracking systems at Montalto di Castro. Courtesy: SunPower Corp.

SunPower announced the commissioning of the third and fourth phases of the plant, totaling 44MW-AC, on December 15th, 2010, and on the same day announced that it had closed on the bond.

On December 27th, 2010, SunPower sold the plant to a consortium of investors including MetLife, Fondo PPP Italia and Voigt & Collegen. SunPower continues to perform operations and maintenance services on the plant, and the site of the plant has returned to some of its original use, with livestock grazing near the PV arrays.

Solar in an accelerated time frame: Rovigo PV plant completed in nine months

SunEdison began construction on the Rovigo in February 2010. Equally remarkable to its size, the process of transforming the site into the 70MW-DC plant took a mere nine months. “With construction completion in less than one year, we believe this deployment signifies a new milestone for the industry and will become the standard for future mega projects,” states SunEdison President Carlos Domenech.

“SunEdison has once again demonstrated its capabilities and expertise in developing large-scale solar projects while helping government agencies promote renewable energy initiatives.”

: 70MW-DC Rovigo PV plant. Courtesy: SunEdison

SunEdison initially developed the plant with Banco Santander, hiring Isolux Corsan for the construction of the plant, but also gives credit to Italian government officials.

“The deployment of the Rovigo project within this time frame was made possible thanks to the commitment of our project partners and local and regional authorities,” said SunEdison EMEA General Manager Pancho Perez.

The successful completion of this plant in such a short time frame has been widely praised, including by the Italian government. In a letter to SunEdison CEO Carlos Domenech, Italian Minister for Economic Development Paolo Romani, congratulated SunEdison for their achievement, referring to the challenges of energy supply in Italy and the project’s importance to economic growth.

PV modules from four different manufacturers

The 2010 global boom in PV installations, led by Germany and Italy, also led to difficulties sourcing modules for the plant. In the end SunEdison sourced the polycrystalline modules for the plant from four different manufacturers - Canadian Solar Inc. (Kitchener, Canada), Chint, Hanwha Solar One Company Ltd. (Qidong, China) and Trina Solar Ltd. (Changzhou, China).

: Courtesy: SunEdison

The plant uses Bonfiglioli Riduttori SpA (Bologna, Italy) inverters, with Areva cabins. It is connected by 840km of cables and 50km of pipes, with another 914km of steel profiles used to support the panels.

The plant is mounted on fixed-tilt structures, which SunEdison estimates comprise 6,090 tons of metal. Additionally SunEdison uses a SEEDS system for monitoring output.

SunEdison estimates that 350 workers were employed in the construction of the plant.

Rovigo sold to First Reserve

Due to attractive feed-in tariff rates for solar PV through the nation's Conto Energia policy, the plant represents an attractive energy investment. On October 4, 2010 SunEdison announced that it has sold the plant to First Reserve Corporation through a previously announced joint venture for EUR$276 million (USD$372 million).

FirstReserve has announced the execution of a EUR$276 million project finance facility for the project with banks including Banco Santander, Unicredit Corporate Banking, Dexia Crediop, Natixis, Société Générale and Credit Agricole. Under the sale, SunEdison will continue to operate and maintain the plant.

: Green power production in Italy: Montalto di Castro PV plant. Courtesy: SunPower Corp.