July 2010 Issue of Wines & Vines

Managing Solar Power Efficiently

Tolosa directs and analyzes solar use with high-tech tools

by Thomas Ulrich
Tolosa Winery solar installation

  • Tolosa Winery in California’s Edna Valley uses many high-tech tools to maximize the efficiency of its new solar setup.
  • Federal and state subsidies reduced the investment in solar power significantly.
  • A medium-size winery and tasting room can recoup the cost of the solar array in six-and-a-half years.
  • Tracking solar energy use encourages staff to operate the vineyard and winery with a longer view.

Like most farmers, Jim Efird, co-owner of Tolosa Winery, pays close attention to the one variable he cannot control. And while he can’t influence the weather, Efird and a growing number of Central Coast winemakers have harnessed one of the region’s most abundant sources of renewable energy.

Part of the 22,400-acre Edna Valley AVA, the winery overlooks a gap between the San Luis and Santa Lucia mountains that rises 450 feet above sea level and stretches several miles east of the Pacific Ocean. The valley’s latitude, endless cycle of foggy mornings, breezy afternoons, cool nights and east-west exposure generate a long growing season with the sun shining directly overhead.

It is nearly noon, and the winery’s 3-acre solar farm is converting radiant energy into 390 kilowatts (kW) of electrical power. Hundreds of electronic trackers equipped with global positioning systems adjust solar panels to follow the arc of the sun. Electricity flows from two refrigerator-size DC/AC inverters to the winery, the tasting room and the power grid.

At just 2,205 growing-degree-days—a cool region by Winkler Scale standards—the Edna Valley is surprisingly well suited for solar power. Tempered by morning fog during the hottest months of the year, the region’s average daily maximum temperature is 70ºF. Solar panels are most efficient around 77ºF, and they absorb sunlight even on cloudy days.

“It makes sense to run our business with a clean, renewable source of power,” Efird says. “It’s efficient and helps us produce wine more sustainably.”

Programming the remote
During summer 2009, Efird removed 2,600 vines from the vineyard closest to the winery so that SunPower Corp. technicians could install 2,508 solar panels (left). Like the 102 acres of Syrah and Pinot Noir that he left untouched, Efird aligned the panels north-south to capture as much sunlight as possible. Capable of delivering 539 kW of power, the solar farm can supply 95% of the electricity required to operate both the winery and tasting room.

“We launched the solar system last August,” Efird says. “During the three-month harvest—the peak of our demand—the total electrical bill was $9,765, an expense we expect to recover in May, June and July. The cost of electricity for 2008 harvest was $85,580.”

A field station adjacent to the two inverters collects data about radiance of the sun, air temperature, rainfall and wind speed. It sends the information to a local controller that determines the angle of the sun and updates the position of the solar panels. It can lower the panels in high wind or raise them for a rinse during a rainstorm.

Web-based tools track production and demand instantaneously. They store data, charts, graphs and statistics, and download tools for monitoring energy patterns and demand. The staff can predict peak loads, compare production to demand, evaluate time-sensitive rates and then schedule work around peak periods to lower costs.

During daylight hours, the inverters send electricity to the power grid, from which PG&E (Pacific Gas & Electric) delivers it to other customers and then credits the winery. When demand at the winery and tasting room increases, the electricity flows back to Tolosa. “We refrigerate a lot of wines during the off-peak hours so that we don’t pay higher rates for using electricity during the day,” Efird says.

Recently the cost of lighting, heating and cooling the winery and tasting room has fallen for another reason. “Since we installed the solar system, the team on the cellar floor is more aware of the power needed to operate the facility,” Efird says. “The less power we use, the more money we save.”

A 30% federal tax credit and a state subsidy reduce the initial investment. At current electrical and interest rates, Efird estimates that he could recoup the cost of the solar system for his 75,000-square-foot winery and tasting room in six-and-a-half years.

“By the 2016 harvest, we’ll have recovered our investment. After that, the electricity is free,” Efird says.

The computer alerts the winery and SunPower Corp.’s operations and maintenance team when a panel fails. Within an hour, the computer reports its exact location and dispatches a repair crew. Another fail-safe feature built into the solar power system: PG&E can alert the winery when the grid experiences a high demand for electricity.

Tolosa Winery solar installation
Crews pulled out three acres of vineyard (left) in the Edna Valley to make room for 2,508 solar panels.

Less is more
Shortly after installing the solar farm at the winery in San Luis Obispo, Efird outfitted a 315,000-square-foot custom crush facility in San Miguel, Calif., with a fixed-panel solar array. (The solar panels at the winery track the arc of the sun and are 30% more efficient than the crush facility’s fixed panels.) The San Miguel solar farm is nearly twice the size of the winery and tasting room site, supplying 1,000 kW of electricity to a facility processing nearly six times the volume of grapes.

“It does not make sense to overbuild the solar system,” Efird says. “With energy conservation on everyone’s mind, and new ways to reduce energy use, these facilities will become much more efficient.”

PG&E is a willing partner. The Renewable Portfolio Standard (RPS), an EPA-sponsored program, requires that California public utilities and other retail energy suppliers generate 20% of their power from renewable sources this year, 33% by 2020. (For 2007, 11.8% of all electricity in the state came from renewable sources such as wind, solar, geothermal, biomass and small hydroelectric facilities. Large hydroelectric plants generated another 11.7%.) Beyond California’s borders, 33 states and the District of Columbia abide by RPS requirements or have established goals for increasing the amount of renewable energy businesses use.

California has established subsidies and goals to decrease demand for foreign oil and reduce greenhouse gas emissions. The state subsidizes solar power systems larger than 30 kW for five years, issuing monthly payments based on output. The governor and legislature have created a comprehensive program to reduce emissions to 1990 levels by the year 2020.

The winery’s performance tracker calculates that the solar power system at Tolosa Winery could reduce CO2 emissions by 16,000 tons or 32 million pounds during the next 30 years. That’s equivalent to removing 2,600 cars from local roads. According to the performance tracker, the solar farm has produced 820 megawatt hours of energy, reducing carbon emissions by 435 tons since Efird converted the winery and tasting room to solar power in August 2009.

Changing your mind
The Central Coast Vineyard Team (CCVT) certified Tolosa as part of its Sustainable in Practice (SIP) vineyard certification program during 2009. In addition to conserving energy, CCVT recognized the winery’s vineyard management team for protecting natural habitats, preserving soil, reducing synthetic pesticides, conserving water, improving air quality and enhancing biodiversity.

With more than 30 vineyards from Santa Barbara to Monterey counties now SIP-certified, many winemakers and vineyard managers from Central California are re-evaluating how they care for the earth.

“One of the biggest changes I see is that growers and winemakers are taking a longer term and more holistic look at their operations,” says Kris O’Connor, executive director of the CCVT. “Rather than making decisions on an annual basis and from an economic point of view, they are considering the 5-, 10-, 20-year window that includes not only the financial but also the natural resource side of their balance sheets.”

Their values reflect the growing commitment that many technology-savvy vineyard managers and winemakers make to preserve the land for generations to come.

“We are now part of a culture that is making a difference—one kilowatt at a time,” Efird says.

Thomas Ulrich has written news, features and advertising copy for Time magazine, the Christian Science Monitor and The New York Times. He was a senior writer for Hewlett-Packard for many years and a contributing editor for Sun Microsystems. He teaches journalism at San Jose State University. Reach him through edit@winesandvines.com.


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