Looking to the Sun for Renewable Energy   Practical Winery and Vineyard Magazine, January/February 2004, by Tina Vierra www.practicalwinery.com Wineries in the U.S. (especially in California), have been installing solar energy systems at an ever-increasing rate in recent years. While the energy efficiency and environmental benefits of solar energy have long been known, the initial cash outlay for a solar system has deterred many potential customers. But solar energy advocates and installation companies have capitalized on current state and federal incentives to make solar energy more attractive than ever. Mount Eden Vineyards Mount Eden Vineyards (Saratoga, CA) installed a 20 kilowatt (KW) capacity photovoltaic (PV) solar system in October 2003. (For comparison purposes, the average size for a home solar system is 2.5 KW.) Working with Akeena Solar (Los Gatos, CA), the 14,000 case/year winery chose a $185,000 system. Mount Eden’s system was installed on a hillside near the assistant winemaker’s home, and includes 136 panels of 185 watts each (known as “modules”), and nine “Sunny Boy” inverters. Inverters work to turn the energy current, generated as DC current through the solar modules, to AC current for use in the winery. Some systems are installed with a single inverter with the same capacity as the entire system. Others employ multiple inverters, whose capacity adds up to the total system capacity. At Mount Eden, the winery and solar company agreed on multiple inverters. “Although it was slightly more expensive, we took this approach because with multiple inverters, failure of one will not affect the others, and they operate at a slightly higher efficiency over a single inverter,” says Barry Cinnamon of Akeena Solar. At its peak (during long, sunny summer days), the Mount Eden system will generate 20 KW of power. Annual energy output is a factor of sunlight hours, sun intensity, orientation of the panels, equipment output, and efficiency losses during power transmission or periods of down equipment. Akeena, like other solar system installers in this report, works closely with client wineries to assess not only the amount of energy needed to serve the winery, but the confusing maze of energy rebates, tax credits, and other financial incentives offered by local and state energy programs. “We developed a detailed economic analysis of the system for Mount Eden,” reports Cinnamon. “Mount Eden is on Pacific Gas & Electric’s (PG&E) A6 rate, which is a small, commercial Time of Use (TOU) rate. TOU rates are terrific for PV systems because they generate additional energy credits during summer afternoons — exactly when PV systems create their greatest output. Mount Eden has an annual electric bill of about $7,000. We expect that their bill will drop to $55 — virtually zero.” Incentives for commercial PV systems are significant. The California Energy Commission (CEC) offers up to $4 per kilowatt-hour (KWH) in rebates for a commercial business that applied before June 2003; a $3.80 per KWH rebate for businesses that filed before December 31, 2003; and a $3.60 per KWH rebate after January 1, 2004. As its funds run out, the CEC reduces the rebate by $.20 per KWH every six months. For 30 KW and smaller systems, the California Public Utilities Commission offers a rebate of up to half the net purchase cost of the system. The federal government offers an investment tax credit of 10% on the remaining cost of the system installation after the CEC rebate. The state of California offers its own tax credit (15% until the end of 2003 and 7.5% thereafter). There is a depreciation credit on a PV system from state and federal governments. Some PV systems are set up to feed excess power back to their energy company, making the winery a power producer that is paid for the power it generates. With Akeena helping on all of the state and federal paperwork, Mount Eden expects the $185,000 system to cost only $90,000 in its first year, and to pay for itself within five to seven years of operation. Copyright © Practical Winery and Vineyard Magazine