Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
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Spring 2011
  • Environmental benefits include reduced carbon emissions, reduced reliance on fossil fuels, and the marketing value of going “green” with solar thermal;
  • System cost ROI/payback can be as little as five years for many wineries (this varies widely depending on the size of the system and hot water usage).
“Wineries use a lot of energy on the way to making that perfect wine,” says Rob Smits of Citizen Green Solutions (Santa Rosa, CA), who installed the system at Kunde Family Estate. “They love solar energy savings, and how it fits their plan of long-term sustainability while giving them a competitive edge. Being a ‘green winery’ has a proven record of appealing to consumers who prefer to purchase beverages from environmentally responsible businesses.
“Fortunately, most wineries and breweries have warehouses with large, unshaded roofs, which are ideal for a solar PV or solar thermal installation. Solar thermal systems make good sense for wineries and breweries, which spend a tremendous amount on fuels to heat water for cleaning and sterilization.”
Financial incentives available as of Fall 2010 for solar thermal installations at wineries are:
  • Cash rebates from California utility companies such as Pacific Gas & Electric (PG&E);
  • MACRS (federal accelerated depreciation tax benefit);
  • Federal investment tax credit of up to 30% of system cost;
  • Some county-by-county programs and incentives, such as the Sonoma County Energy Efficiency Program (SCEIP).
Nick Stimmel, PG&E program administrator for the California Solar Initiative (CSI) thermal program, notes the residential solar thermal program was launched in May 2010, and the commercial solar thermal systems program in Fall 2010.
“The commercial solar thermal rebates are retroactive to all projects final (signed off by the local jurisdiction) after July 15, 2009, meeting the program requirements,” Stimmel reports. “We are developing a calculator for this rebate. The system installer will input data for the system to be installed at a winery, and the calculator will generate an estimated
energy savings and rebate amount to file with the utility.”
Large solar thermal projects (larger than 250 kW thermal) will participate in a 70/30 “true-up” payment plan. Predicting system performance using the calculator, PG&E will pay 70% up front on that performance calculation. Then performance of the solar thermal system during its first year of operation will be metered, and the remaining incentive will be paid based on the “true-up” calculation. Basing part of the rebate on real performance of the system could mean larger rebates for a winery if the system performs well. Systems smaller than 250kW will receive a 100% rebate upon installation.
Handbooks for solar thermal installers, and rebate information for wineries, are available at
Kunde Family Estate
Citizen Green Solutions installed a solar thermal system at Kunde Family Estate in early 2010. System output is estimated at 6 million BTUs per year, cutting the winery’s average annual natural gas bill in half. The life of the system is estimated at 30 years, which will save Kunde about $95,000 in natural gas costs over that period.
“Our solar thermal system is used to heat water, which we then use directly in wine processing,” says assistant winemaker Russ Fish. “This is the same type of system installed in many new homes to generate domestic hot water, and was very simple to install. Each of the 50 collectors we have should be able to heat 50 gallons of water by 50°F on a warm, sunny day.”
Kunde’s solar thermal system has:
  • 50 flat-plate solar thermal collectors on the south-facing winery building roof (1,000 square feet of collector surface area);
  • Insulated copper piping containing glycol;
  • One 1,040-gallon storage tank;
  • Two recirculation pumps (one for glycol, one for water);
  • A 120-gallon drain-back tank to collect glycol from the collectors and pipes, to prevent overheating or freezing. When the storage tank reaches 200°F, the system shuts down automatically, and the glycol flows to the drain-back tank;
  • A small electronic controller to control system functions, including temperature set-points, temperature display panels, heat exchanger, and storage tank.
Heat exchanger (top of photo) at Kunde accepts heated glycol from the rooftop solar thermal array and sends the heat to the hot water loop in the winery. When the hot water in the system reaches 200°F or the winery is not using the hot water in the system, the glycol drains from collector pipes to a 120-gallon drain-back tank (bottom of photo) to prevent freezing or overheating.
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