Practical Winery
58-D Paul Drive, San Rafael, CA 94903-2054
phone:415/479-5819 · fax:415/492-9325
email: Office@practicalwinery.com

This article is from the January/February 2004 issue of Practical Winery & Vineyard Magazine. Order current or back issues here.

January/February 2004

BY Tina Vierra

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.

Vino Noceto Winery
Vino Noceto Winery (Plymouth, CA) installed a 10 KW system in the spring of 2002. The system consists of four 2.5-KW panels and four Sunny Boy inverters. An attractive aspect of smaller multiple inverters like the Sunny Boy is that they are mass-produced, making them quicker and easier to replace or repair if they go down.
The 200-ton capacity winery is at 1,500-foot elevation in the Sierra Nevada foothills, and the panels were installed facing southwest for good sun exposure. They are mounted on a sloped (15%) roof. With only four relatively lightweight panels, the winery did not have to reinforce the roof before installation.

The system cost was $110,000, but the winery received an immediate state rebate of 40% of the installation costs. Owner Jim Gullett expects payback in six to seven years, and may install up to 50% more solar capacity in the future.

“Before we installed solar,” he reports, “during harvest, we paid an average energy bill of over $1,000 per month. Since putting in solar, our bills during bottling average about $100 to $300, and other months the bill swings down from $100 past zero to as low as –$50.”

In a 12-month period from May 2002 to May 2003, the winery saved $9,000 on its PG&E utility bills, going from annual spending of $13,800 to just $4,800.

Sierra Vista Winery
Inspired by an open house at nearby Vino Noceto, John and Barbara MacCready of Sierra Vista Winery (Placerville, CA) installed a solar system in September 2003.

“We saw the Vino Noceto installation and asked Premier Power (El Dorado Hills, CA) and another company to give us quotes. We were committed to the project if we could afford it,” John MacCready says. “We also bought a new Europress to replace our old press, and those two projects are significant for a small winery with no deep pockets in a less-than-great economy.”

The gross cost of Premier Power’s system was $100,000. Rebates, tax credits, and depreciation reduced the actual out-of-pocket cost to less than 70% of the gross cost. The solar provider helped the MacCreadys with paperwork for the rebates and tax credits, which were provided in the initial quote. (See Table II for details.)

Sierra Vista’s system is 14.4 KW, installed on the winery operations building at a slope of 1:12, with half of the roof facing southeast and the other half northwest. The panels are Sharp 185 modules as at Mount Eden, with Sunny Boy inverters, and they cover 1,500 square feet of the roof. Just the presence of the panels shading the roof of the building should reduce summer cooling costs by as much as 10%.

At an elevation in the Sierra Nevada mountains of 2,800 feet, the winery can expect few problems with fog or other sun occlusion. “We see fog at the winery once or twice a year, but see fog in the valleys around the winery quite often,” reports MacCready.

Accounting for factors such as fog is important in helping determine what type of solar modules to install. “There are different types of modules for different applications,” explains Deborah Millhollin of Premier Power. “Certain modules are suitable for areas with fog; others are better for very warm temperatures, and others for cool temperatures.”

The Sharp solar panels at Sierra Vista have a life expectancy of up to 30 years and are guaranteed for 25 years. Wineries should check warranties with their solar energy installers, since it is a contingency of some state and federal credit/rebate programs that the systems be under warranty and/or service contract for at least the first five years after installation.

Sierra Vista Winery bottled 8,659 cases of wine in 2002, and crushed 126.5 tons. The building is well-built and insulated, needing no reinforcement to install the solar panels.

Premier Power tied the Sierra Vista system into the electrical grid for “net-metering.” Under the net metering system, once the winery’s own energy needs are met, it can funnel energy back to its utility, PG&E, during peak efficiency times such as sunny summer days.

“The Interconnection agreement we provided means PG&E now considers the winery to be a power producer and not a consumer. Sierra Vista will pay a utility bill annually, paying only the difference between what it produces and what it uses,” adds Millhollin.

Bokisch Ranches
Markus Bokisch is using solar energy to power vineyard irrigation in Clements, CA. A 7.5 KW system has three inverters, provided by Renewable Technologies, Inc. (RTI) of Sutter Creek, CA. The vineyard is on the net metering system with PG&E.

Installed on a shop roof at Bokisch’s vineyard, the system sends about 50 KW per summer day to the power grid. At night, 35-horsepower pumps pull energy off the grid to water the vineyards.

“Right now, we’re producing about 35% of the energy we need to power the irrigation for 60 acres, our shop, and a home,” Bokisch reports. “We’ll need a 22 KW system for 100% of the power we need in summer, 50% in winter. We will install more panels and hope to be up to 22 KW by spring 2004.”

The modules are on a 22% incline, in an area with low dust, and they achieve about 78% average annual efficiency. To keep the panels efficient, simple maintenance with sprinklers to rinse dust and dirt is planned.

Bokisch hopes more farmers will get into solar. Indeed, he has seen enough interest from fellow growers that he finds himself guiding informal tours of his solar energy system and educating his peers.

Flatbrook Farms
The Clear Skies Group is a renewable energy installer located in Long Island, NY, with offices in California. CEO Ezra Green has been trying to get Long Island vintners interested in solar energy, but is hampered by New York’s net metering program which does not allow power providers to “bank” energy savings they feed back to the grid for future use.

“We do a lot of farms in surrounding states, and are beginning to work with small wineries in California,” he reports. “Small farms and businesses are the perfect candidates for solar use. The process for getting started is very simple. A grower need only collect 12 months of utility bills, then fax or mail them to us. We give a working proposal recommending system size, potential savings, and a list of components we’d supply. Then we visit the site and walk the owner through the process.”

Clear Skies’ specialty has been working with water companies like World Water in New Jersey, designing systems to power irrigation and water management. Flatbrook Farms in Montague, NJ, is an example. Clear Skies installed three systems (10, 8, and 4 KW for a total 22 KW system) at Flatbrook.

The solar panels are Sharp brand (Clear Skies uses mass-produced name brands for cost reduction and ease of repair or replacement), with Sunny Boy inverters, mounted with galvanized piping set in 12-inch pilings. Green describes the panels as “single crystal” panels, which have the highest ratings for efficiency of energy collection. Power flows through the inverters, converts to AC power, and then goes into the circuit breaker panel for Flatbrook’s consumption.

Green and his team monitor new systems closely at first. “For the first three weeks, we monitor the system weekly. Then we come every two weeks for the next six weeks; then every couple of months for the next six months. There are very few problems with solar energy systems,” he reports.

Solar energy systems require little to no maintenance, Green notes. Clear Skies systems use no moving parts.
Another Clear Skies customer, Rex Farr in Calverston, NY, is participating in a pilot program to bring renewable energy to farms currently dependent on fossil fuels. Farr’s 30 acres of vines will get a new drip irrigation system powered by solar energy.

“By shutting down one diesel generator,” Green states, “you are eliminating tons of pollutants from the air. If we change our energy-producing methods, the effect on the environment will be profound.”

Seavey Vineyard & Winery
Seavey Vineyard (St. Helena, CA) had a 10 KW system installed by Renewable Technologies in February 2003. The 3,500 cases/year winery installed 64 modular panels and four inverters. Half of the modules were installed on a shed with a south-facing roof and half on a custom-designed free-standing shade structure.

“The choice of the shed was an aesthetic and safety decision,” says Will Seavey, son of owners Mary and Bill Seavey and the driving force behind their switch to solar energy. “We wanted to keep the winery building looking nice for visitors, and with so much activity around the main building (children often play there, for instance), any kind of objects could have landed on the roof and damaged the modules.”

But because electricity loses force over distance, the fact that the power had to travel more than 500 feet to the appropriate meter presented a challenge. Darryl Conklin of RTI advised and installed transformers to “boost” energy as it traveled down a buried power line connecting the solar system and meter. The voltage is kept high, but “transformed” back to low voltage just before arriving at the meter. Thus the energy gets back to the meter at its full power rating.

Using the common method of multiplying the number of kilowatts in its system by the average number of hours of sunlight per day, Seavey estimates the solar energy system produces an average of 55 KWH per day. It produced up to 75 KWH of power on a long summer day, and they expect 35 to 40 KWH on cloudy winter days.
Seavey notes his monitoring of meter readings indicates the solar system provides two-thirds of the winery’s energy needs. During the summer, the system has saved the winery about $450 per month, and savings in winter will be about $170 per month. The winery also received $40,000 back from the state rebate program on initial installation costs. “We estimate financial payback in five years,” concludes Seavey.

Domaine Carneros
The new Domaine Carneros (Napa, CA) Pinot Noir production facility is one of the largest projects of energy efficiency ever attempted in the worldwide wine industry. When planning began on the winery’s new 23,000 sq. ft. addition, it was decided to aim for maximum energy efficiency.

Overseen by Eileen Crane, president, Sid Lipton, (owner’s consultant), and Wright Contracting (general contractor) [Santa Rosa, CA], the building’s grand opening was on June 21, 2003 (the summer solstice). The construction included work from over 40 subcontractors and suppliers. PowerLight of Berkeley, CA, was the solar installer.

The 120 KW PowerGuard system consists of 688 lightweight solar panels mounted flat on the building’s rooftop, and a single 120 KW inverter. The system initially cost $850,000, but the winery immediately claimed a PG&E rebate of $425,000. PowerLight projects a maximum potential of 90% efficiency from the system, which is expected to generate 40% of the winery’s energy needs.

Maintenance of the solar panels consists of washing them off once or twice each month. Projected payback on the system is just four years, factoring in all tax credits, accelerated depreciation credits, the amount of power generated and its attendant utility savings, and the energy efficiency of the building itself.

In addition to 2-inch thick solar panels covering the roof and giving some sun protection, the winery installed R35 roof insulation. Rigid foam insulation on the exterior face of concrete block walls contributes to a total eleven inches of wall and insulation thickness.

Another feature of the building’s energy efficiency is the Sunpipe® Daylighting System. Instead of installing traditional skylights which offer unfiltered light through large openings in the roof (thus allowing heat in, which is counter-productive), Lipton did some Internet research and found the Sun Pipe Company in Elgin, IL. Greg Miller is Sun Pipe’s owner and co-inventor of the system.

“Sun Pipes ‘pipe in’ daylight from above the roof using aluminum pipes with a super-reflective interior,” explains Miller. “Fifteen 21-inch diameter, 5-foot long Sun Pipes were installed between solar panels on the roof to illuminate the fermentation cellar with diffuse daylight. The diffusion occurs at the bottom of each pipe (18 feet above the floor) via a white diffuser dome which glows with however much daylight is available.”

“The greatest category of energy savings is not electric lighting,” notes Miller. “It’s HVAC savings. Sun Pipes remove only 1/10 of the roof insulation that skylights remove, and they introduce comparatively little solar heat gain. This translates into massive HVAC energy savings for air-conditioned spaces.

“The greatest financial reward is the effect that daylight has on employees. Fewer sick days, fewer vision and attention-related accidents, and increased productivity are some of the human benefits of daylighting a workplace.”
Mike Davidson of Industrial Refrigeration and Process Piping (Healdsburg, CA) worked on energy-efficient refrigeration for the facility. “The industrial refrigeration system installed at Domaine Carneros consists of two 20-ton (a system designed for a future 20-ton compressor) open-drive, reciprocating compressors with external capacity control,” explains Davidson, “connected to a flooded glycol chiller providing cold glycol to the winery’s new fermentation tanks and barrel storage room.

“This system uses many efficient components, but two of the primary benefits of the newly installed chiller system are the flooded glycol chiller and operation of the programmable logic controller (PLC) installed on the package.

“The flooded glycol chiller is significantly different than a conventional direct expansion-fed shell and tube chiller. Flooded chillers operate based on natural convection due to the difference in densities between the solid column of refrigerant liquid feeding the chiller and the gas/liquid mixture being boiled by the glycol (heat is absorbed by the glycol returning from the system).”

Some of the energy-efficiency benefits of the flooded glycol chiller include: substantially higher heat transfer coefficients; more efficient use of the heat exchanger surface; a wider range of operating temperatures; and the system can obtain a closer refrigerant-to-glycol approach temperature (as close as 3F), which increases the compressor’s capacity and reduces its horsepower requirement.

A programmable logic controller (PLC) installed on the package provides a measure of energy efficiency, adds Davidson. “This method of compressor loading and unloading provides precise control without over- or under-shooting the target temperature, which yields a much smoother system operation and reduction in electrical usage through reduced demand and use charges.”

Crane is proud of the finished facility. “The installation marks a significant milestone in Domaine Carneros’ continuing efforts to achieve sustainability in the production of premium wines.”

Ridge Lytton Springs Winery

Solar energy panels were installed at Ridge’s new Lytton Springs 18,000 sq. ft. facility (Healdsburg, CA) in September 2003. The new facility will produce red wines, predominantly Zinfandel, and like Domaine Carneros, was designed with energy-efficiency in mind. (See January/February 2003 PWV.)

The 66 KW PowerLight system contains two panel arrays on two slopes of the rooftop. The roof is pitched at 17 degrees and 35 degrees on slopes facing due south. The panels were installed a few inches above the roof, thus doing double the cooling work by blocking sun and by allowing cooler air to circulate along the surface of the roof.
Ridge’s system has two 30 KW inverters. It is expected to generate 80,000 KWH/year and was set up for net metering so that Ridge can sell excess power to the utility grid at peak times. Mark Vernon, chief operating officer at Ridge Vineyards & Winery, anticipates that the winery will use most of the energy it produces, given the size of the facility, but says it’s a bonus that the winery will be in need of the largest amount of energy at the same time that it is producing the most — in the summer and harvest months.

PowerLight helped Ridge file all its paperwork for incentives and net metering. The winery recouped 50% of the initial cost of the system in rebates, and is eligible to receive up to 25% more of the cost back in tax credits from the state and federal governments next tax year.

Evergreen Valley Winery
Evergreen Valley (Luthersburg, PA) is uniquely located to use solar energy. Owners Mark and Lorraine Gearhart planted a 10-acre vineyard in a reclaimed strip coal mine in Pennsylvania Amish Country, where little electricity service is available.

The winery is not connected to an electric power grid. “There is no cash incentive program in our area to install solar or wind power, and a substantial power company charge to even hook us up,” says Gearhart. “So we opted out totally and built our winery and home here to require no outside power.”

The winery building is on a ridge, with solar panels installed facing south at a 45-degree angle. In 1991 when he established the vineyard, Gearhart installed one 40-watt solar panel and a windmill. In 1997, six 100-watt solar panels were added. In 2003, a second windmill and six more panels brought the total energy production to 1.25 KW. Gearhart, a licensed professional engineer, aims to eventually increase the solar energy capacity to 2.5 KW.

Since there is no electricity grid to accept power, the winery uses 18 200-amp, 6-volt golf cart batteries to store energy. The batteries can hold a combined total of 20 to 25 KW of energy. The six bearing acres of vineyard yield about two tons each. The winery has crushed up to 12 tons per year using an electric crusher and a Willmes bladder press. Solar and wind power meet all the winery’s crush, bottling, computer, cash register, and lighting needs, as well as powering Gearhart’s home.

“We don’t have the large numbers of installed panels that others do, but without a tax incentive, we have accomplished a totally self-sufficient business on that tiny amount of energy by being very efficient in the way we use what we do have. We’re about wine first — we’re big on things like battery-powered forklifts and other labor savers.”

Stargazers Vineyard
Stargazers Vineyard (Coatesville, PA), a 2,000-case winery with 14 vineyard acres in southeastern Pennsylvania, is on an electrical grid, so the winery was able to take advantage of public utility rebates, and state and federal tax credits to defray some installation costs. Accelerated depreciation credits mean the winery will see payback on their system in 15 years.

Owners John and Alice Weygandt strive to keep their operations and home “green.” The winery, built into a hillside, requires no additional heating or cooling. Their nearby home is a passive solar “envelope” design. Rainwater collected in cisterns from the winery rooftop is used for cleaning in the winery.

A 30-panel solar energy system will generate up to 4800 KWH/year of power for electrical needs. The BP solar panels are on the south-facing winery roof, which has a 26 slope.

Prior to going solar, the Weygandts purchased electricity from The Energy Cooperative, a Philadelphia-based nonprofit electrical supplier which purchases solar energy from residences and businesses who become renewable energy producers. Now Stargazers Vineyard has become an energy producer, and plans to sell any excess energy produced by the solar system to the Energy Cooperative.

Rodney Strong Vineyards
Installation of a 766 KW system from PowerLight at Rodney Strong Vineyards (Healdsburg, CA) in October 2003 became the largest solar energy installation in the wine industry. Installed on a south-facing roof of the winery’s 100,000 sq. ft. barrelhouse at a 5 slope, 4,032 panels with three large inverters make up the system. The panels are fixed, but mounted a few inches above the roof to give both shade and cool airflow along the roof.
Tobin Ginter, chief financial officer, was instrumental in crunching the numbers and pushing to install solar energy. He reports the gross cost of the large system to be about $4 million, but the net will be only half that, and payback will take about nine years. The system should supply most of the 600,000-case winery’s power needs, averaging 250,000 KWH per month of energy output, and peaking during harvest at up to 420,000 KWH per month.

PowerLight also installed new lighting at Rodney Strong Vineyards for further power savings. Over 400 high-efficiency, linear flourescent fixtures and lamps with electronic ballasts were placed throughout the wine production and case good storage areas. The system includes sound and motion sensors so that only occupied areas are illuminated.

The new lights generate less heat than older lighting at the winery, reduce lighting electric demand by about 500,000 KWH per year, and deliver light at a higher color rendering index (CRI), which matches natural light closely, increases visual acuity, and makes the lighting more comfortable to the human eye.
“Solar electrical systems have never been more suitable to our industry,” notes Tom Klein, chief executive officer. “The combination of solar technology improvements with customary flat-roof winery buildings and their sunny locations, have made renewable energy more commercially viable.”

Never a better time
The wineries and renewable energy companies in this report all stressed that now is the time for wineries and vineyards to get solar or other renewable energy installed if they can.

State and federal incentives have never been better. But state incentives are beginning to diminish as funds, such as the CEC Renewable Energy Program, run out with no sign of replenishment from the financially-depressed state of California. In addition, the California tax credit reduces by half in 2004.

Darryl Conklin of Renewable Technologies, Inc., (RTI) has appeared before state committees with proposals and recommendations for keeping and increasing incentive programs. A fierce advocate of renewable energy, he fights not only to educate government officials but the general public also. RTI has built a special trailer containing working examples of wind and solar power to take to schools and businesses for demonstrations.

“It’s a continuing fight for education and funding,” Conklin says. “We have to fight the utilities also. PG&E wrote legislation to charge net-metering energy producers a nickel per kilowatt to send power to the grid with the argument that PG&E built the grid in the first place. Luckily that got defeated.”

At a March 2003 hearing before the California Energy Resources Conservation and Development Commission, Conklin recommended that the commission, from its budget, send at least $1.35 million annually to the Renewable Resources Consumer Education Account, and $6.08 million annually to both Emerging Renewable Resources and to the New Renewable Resources Account.

Conklin also seeks better oversight of utility companies to ensure that renewable energy producers are getting what they should from net metering and other systems, and that monopolies don’t strangle small businesses as renewable energy producers.

He also encourages regulations that don’t choke renewable energy systems and eat up allocated funds which could otherwise go to encourage more consumers to become renewable energy producers.

Exploring solar energy
Wineries and growers who consider using solar energy should consult their state renewable energy advisory agencies (see Resources at end of this report), and work closely with the solar provider they choose to file all paperwork required and meet all deadlines to receive rebates, tax credits, and depreciation incentives. They should also carefully review how net-metering works within their local utility system if they intend to produce enough power to feed back to the power grid.

Actually receiving money back on a solar installation depends on careful, informed planning beforehand.





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