Solar-powered viticulture in California reaches new heights with Foster’s Wine Estates’ PV foursome

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Tom Cheyney

Tom Cheyney is former senior editor of PV-Tech / Photovoltaics International magazine. A veteran technology journalist / editor / blogger, he covered the semiconductor, microelectronics and solar sectors for many years - since fax machines were state of the art. His PV-Tech blog has become a must-read for industry insiders and observers. He was also chief editor of "The Rise of Thin-Film Solar Technology" book published in early 2010.

Warehouses, and Wal-Marts, and wineries, oh my! The proliferation of commercial-scale solar PV power systems in California over the past year or so has been nothing short of impressive. Although utility and residential installations have also grown significantly, the use of large rooftops and ground-mount-friendly open spaces for module arrays between a few hundred kilowatts and a few megawatts in size has become one of the biggest solar stories.

Since the Golden State is one of the major wine-producing regions on the planet, benefiting from awesome insolation as part of its most excellent assemblage of terroir, announcements of yet-another deployment of a PV system at yet-another winery has become a regular part of the solar news flow. With scores of vineyards now reaping the sun's energy, it has become almost de rigueur among the viticutural set to install those renewably energetic rows of panels.

Still, when a winemaker announces the activation of several PV installations at once, including what is called "the largest solar energy system by a U.S. winery," the news merits a deeper look.

Foster's Wine Estates Americas, a unit of Foster's Group (AKA the company that brought us "that's Australian for beer, mate"), has turned on four new installations, including the 1.341-MW system at Beringer Vineyards in Napa Valley (partly shown above)--the biggest of its kind. Add in the new bronze medalist in the winery PV system scale competition--Asti's 1.152-MW rooftop array--and the smaller Etude (103.49 KW) and Stag's Leap (225.79 KW) installations, and the company now sports more than 2.82 MWs of PV power at the sites.

Together, they will generate some 3.85 million kilowatt-hours in the first year, a fair flow of sun-juice to help make that wondrous fermented elixir.

Perpetual Energy Systems (PES) financed and developed the systems, combining conventional financing, construction and permanent debt with equity, along with the federal energy tax credits program to fund the whole enchilada without any capital from Foster's. PES owns the PV panels and will keep the renewable energy certificates and carbon credits garnered from the system's actual kilowatt-hour output.

Codevelopers the Bright Group and Stellar Energy Solutions also lent their hands to the project. Bright took care of the predevelopment engineering and system design, including building allocation and roofing specifications.

Solar integrator Stellar Energy was the project's engineer, codeveloper, and general contractor responsible for the day-to-day operations and oversight of all subcontractors during construction. Stellar will also will be on point as the lead partner overseeing continued maintenance and operations of the solar project during its 25-year term.

Stellar's Chris Phipps provided more project details via email. The company's director of marketing says that discussions among the soon-to-be partners began in summer 2007, with the dotted lines on the master LOI signed in April 2008. Construction started in July 2008, with the systems switched on during the last week of December. (Nothing says happy holidays like solar power, after all!)

Sharp 216- and 224-W (DC) PV modules--12,908 of them (6104 in the half-dozen different Beringer arrays)--were chosen for the fixed rooftop installations, while the range of inverters--from 75- to 500-KW models--came from Satcon. In both cases, the brands were tapped because they have the "best quality for a large commercial project," according to Phipps.

The more than 2.82 MW DC of installed PV power will turn into about 2.38 MW of usable AC electricity power for the barrel rooms, cellars, and warehouses, once it flows through those 0.945- and 0.96%-efficient inverters and the rest of the balance-of-system components. A Draker system monitors "site loads as well as production on a 15-minute interval basis to provide the detailed performance data we need to calculate 'avoided costs,' [since] Foster's is paying 90%" of those costs, he added.

Next time you pop the cork on a bottle of Souverain or Cellar No. 8 or any number of California wines, savor the flavors knowing the vino might come from a photovoltaically assisted vintage.