Managing Energy Costs in Wineries

There are many systems that offer substantial energy-saving potential in wineries, including refrigeration and cooling systems, compressed air systems, lighting, and packaging systems; there are even savings to be gained in tasting rooms and gift shops. As a result, wineries can benefit greatly from a variety of strategies that are easy to implement and that are either free or cost very little.

Turning things off seems simple, but remember that for every 1,000 kilowatt-hours (kWh) you save by turning things off, you save $120 on your utility bill, assuming an average electricity cost of $0.12/kWh.

Lights. Turn off lights when they are not in use. Occupancy sensors and timers can help, but a less expensive alternative is simply to develop standard protocols for shutting lights off during closed hours—particularly in tasting rooms and gift shops.

Electronic displays. Many stores or tour areas have electronic displays that are left on even after open hours. Consider shutting off the displays during closed hours, either manually or with simple timers.

Some equipment cannot be turned off entirely, but turning it down to minimum levels where possible can save energy.

HVAC temperature setbacks. During closed hours, turn temperature settings down in warming seasons and up in cooling seasons. Smart thermostats can help automate this process.

Peripheral and back rooms. Make sure that HVAC settings in stockrooms, offices, and other peripheral rooms are at minimum settings.

Because refrigeration and cooling generally use the most electricity in wineries, they are often a great starting point for making energy-efficiency improvements.

Tank insulation. Making sure that the storage tanks used for fermenting and aging wine are well-insulated is an easy and effective way to reduce energy consumption. Multiple types of insulation are available, including spray-on (for large applications), foil-covered bubble wrap, and rigid foam. According to BEST, adding insulation to tanks should generally reduce refrigeration energy use by about 25 percent, though exact savings will vary depending on the specific tank and insulation used.

Install floating head pressure on glycol chillers. Glycol is the standard refrigerant for industrial facilities because it absorbs heat efficiently. BEST states that allowing glycol chiller head pressure to “float” based on outdoor wet-bulb temperatures can reduce the power consumption of the refrigeration compressors by 5 to 20 percent.

Raise the temperature and pressure setpoints. Tartrates—small crystals that form when tartaric acid mixes with potassium in the wine at low temperatures—are tasteless and odorless, but they’re considered unsightly. They are frequently removed using a process called cold stabilization, which requires wine to be chilled to between 25° and 36° Fahrenheit (F) and then reheated. This process is only necessary when the wine can’t easily be maintained at the optimal 59°F due to cold outdoor temperatures.

Also, refrigeration systems will run at higher efficiencies when operated at higher suction-pressure setpoints. Raising glycol temperature will raise the associated suction pressure; this change can result in a savings of 2 to 3 percent of refrigeration compressor energy for each degree increase in suction temperature.

Nighttime air cooling. Bringing in low-temperature outside air during the night to provide cooling can reduce electricity consumption and lower peak power use during the day. This is particularly effective in spaces where outside-air circulation was not previously required, such as warehouses, offices, and cold-stabilization areas. According to BEST, savings can easily add up to about 20 percent of overall cooling energy.

Air infiltration through doors. By employing air sealing and ensuring that doors between refrigerated and nonrefrigerated areas are properly closed whenever possible, BEST estimates you can save as much as 15 percent of your total refrigeration energy consumption.

Properly sequence compressors. Compressors operate most efficiently at full load. In a refrigeration system that employs multiple compressors, the most efficient operation entails sequencing compressors based on their loads and respective efficiencies and ensuring that only one compressor at a time operates at part load.

Conveyors are widely used in bottling and palletizing; in many facilities, they run even when not fully loaded. Only running conveyors when they’re necessary can reduce energy consumption and demand while also conserving lubricants and water. Automation controls can make conveyer management easier, though it can be done manually as well.

Although compressed air is often viewed as an essentially free resource, BEST estimates these systems typically account for nearly 10 percent of overall electricity consumption in wineries, and they’re often poorly designed or maintained. Optimizing compressed air systems can lead to significant savings.

Match your supply to your load. Generate compressed air only at the pressure required—halving pressure can result in energy savings of more than 50 percent, according to BEST. Additionally, sequence your machines to ensure that when the demand is at less than full capacity, some compressors are entirely shut off, rather than having several operating inefficiently at part load.

Check for leaks. Air leaks in a compressed air system are a major source of energy loss—they can as much as double the cost of compressed air. Because leaks also result in lower pressure at the point of use, they can cause operators to set pressure levels higher than would otherwise be necessary. Leak detectors can cost anywhere from $1,000 to $15,000 to install, but they will often pay for themselves the first time they’re used on a system that hasn’t been maintained (Table 1).

Table 1: Leak detector savings

The US Department of Energy’s Advanced Manufacturing Office measured the energy savings, dollar savings, and simple payback periods of finding and repairing compressed air system leaks in four industrial facilities.

In many wineries, lighting accounts for 8 to 20 percent of electricity consumption. Improving the efficiency of your lighting systems can be a straightforward and inexpensive way to save energy.

Employ daylighting. Daylight can improve the ambience of an office and reduce the need for electric lighting. Dimming ballasts and daylighting controls can be used to reduce the amount of electric light needed when daylight is present.

Install occupancy sensors. Areas that are not consistently occupied—such as storage rooms, restrooms, back offices, and walk-in refrigerators—are ideal places for occupancy sensors. BEST estimates that lighting these low-usage areas only when they’re in use can save between 30 and 75 percent of the lighting energy consumption in those areas; occupancy sensor installations typically yield simple payback periods of one to three years.

Making sure that your HVAC system is regularly cleaned and serviced can help prevent costly heating and cooling bills.

Check the economizer. Many air-conditioning systems use a dampered vent called an economizer that draws in cool outside air when it is available to reduce the need for mechanically cooled air. If not regularly checked, the linkage on the damper can seize up or break. An economizer that is stuck in the fully open position can add as much as 50 percent to a building’s annual energy bill by allowing hot air in during the air-conditioning season and cold air in during the heating season. Have a licensed technician check, clean, and lubricate your economizer about once a year, and repair it if necessary. If the economizer is still operating, have the technician clean and lubricate the linkage and calibrate the controls.

Check air-conditioning temperatures. With a thermometer, check the temperature of the return air going to your air conditioner and then check the temperature of the air coming out of the register that is nearest the air-conditioning unit. If the temperature difference is less than 14°F or more than 22°F, have a licensed technician inspect your air-conditioning unit.

Change the filters. Filters should be changed periodically—every one to six months. More-frequent changes may be required when the economizer is in use, because outdoor air is usually dirtier than indoor air.

Check the cabinet panels. On a quarterly basis (or after filters are changed), make sure the panels to your packaged rooftop air-conditioning unit are fully attached, with all screws in place and all gaskets intact so that no air leaks out of the cabinet. Chilled air leaking out can cost $100 per rooftop unit per year in wasted energy.

Clean the condenser coils. Check the condenser coils quarterly for either man-made or natural debris that can collect in them. At the beginning and end of the cooling season, thoroughly wash the coils.

Check the airflow. Hold your hand up to the registers to ensure that there is adequate airflow. If there is little airflow, or dirt and dust are found in the register, have a technician inspect your unit and ductwork.

Longer-term energy-saving solutions should also be considered. Although the conservation measures covered in this section require more extensive implementation and larger monetary expenditures, they represent good investments. Most will not only save money, but will also enhance the winemaking environment and the comfort of your buildings. Ask your local utility representative for more information about initiating such projects.Refrigeration and Cooling

Upgrade chillers. Installing high-efficiency chillers with variable-frequency drives (VFDs)—also called adjustable-speed drives—will reduce both electricity and maintenance costs by roughly 20 percent. The Danfoss Turbocor is one such chiller; its models are much more efficient at partial load than 300-ton or smaller screw, centrifugal, or reciprocating chillers. Other benefits of the Turbocor include lower maintenance costs and noise levels, plus a small, modular build.

When it comes to centrifugal compressors, another option is to install a VFD. Properly used, they can be an inexpensive alternative to upgrading.

Install a desuperheater on the glycol chiller compressor’s exhaust. A desuperheater is a secondary heat exchanger that’s installed between the evaporative condenser and the refrigeration compressor. This technology can simultaneously heat the boiler makeup water and reduce the amount of heat that is being wasted by the condensers. Installing a heat exchanger can result in 10 to 20 percent savings in natural gas costs.

Use flotation for white juice settling. Flotation can be an alternative technique to using refrigeration to settle the solid byproducts of white wine to the bottom of the tank. This technique uses compressed air or nitrogen gas to saturate the grape juice or must. The gas bubbles stick to the solid particles and float up to the top, forming a cap of foam that can then be easily removed.

Use electrodialysis instead of cold stabilization. BEST mentions that a process called electrodialysis, which uses membranes in conjunction with an electric current, can reduce energy consumption by nearly 90 percent compared to cold stabilization because the need for freezing and reheating is effectively eliminated. Because membrane replacement can potentially be costly, check with a manufacturer first to ensure that this measure will be economical for your particular winery.

Install destratification fans. Destratification ceiling fans can help to maintain a consistent air temperature throughout a cellar or warehouse, resulting in lower cooling requirements.

Create cave storage. Storing barrels of wine in caves rather than in above-ground buildings can be an effective way to save energy while ensuring that temperatures and humidity levels remain at ideal levels on a continual basis. Payback periods vary, but digging new caves to correspond to increases in capacity can be particularly cost-effective.

Motors are widely used in fan and pumping applications and are a good target for efficiency improvements. According to BEST, pumping systems in particular can account for 10 to 25 percent of electricity consumption in wineries, and simple changes can lead to significant energy savings.

Install variable-frequency drives. VFDs match motor output torque to real-time load. BEST estimates that energy savings from adding an VFD can be as high as 45 percent, depending on the application and motor duty cycle. VFDs can also improve power factor, potentially resulting in fewer utility surcharges. BASE Inc. recommends VFDs as good fits for existing screw compressors, condenser fans, glycol circulation pumps, and air-handling fans; in these applications, simple payback periods can range from one to six years.

Use multiple pumps. In many cases, using multiple smaller pumps can be a cost-effective and efficient way to handle varying loads, because they can be run closer to full capacity rather than at a less-efficient part load. This measure can save anywhere from 10 to 50 percent of energy used for pumping.

Downsize your motors. Motors are often more powerful than necessary, resulting in needlessly high energy consumption and peak power draw. If possible, consider replacing oversized motors with smaller units to better match the needed load.

Upgrade to high-efficiency motors. When considering whether to repair or replace aging motors, keep in mind that new, more-efficient units can save significant amounts of energy and are usually subject to short simple payback periods.

Packaging comprises everything from bottle-filling to palletizing and can be a major source of energy consumption in wineries. Although there’s very little hard research available for packaging processes that’s specific to wineries, we did find that heat recovery is a verifiable option to save energy in your packaging processes. To help ensure that labels stick, wine bottles are often heated to about 50°F. Adding a heat-recovery system that utilizes refrigerator waste heat can help drastically reduce the energy used for this purpose while also reducing water consumption and maintenance costs.

Upgrade to LED lighting. LEDs offer several advantages over conventional light sources, including high efficiency, long life, and superior control. These characteristics, along with falling prices, have made LEDs a viable solution for a growing number of applications, including exit signs, task lighting, recessed downlighting, and ambient lighting. You can upgrade to LEDs just about anywhere—there are LED options that are appropriate for warehouses and processing and others that are perfect for gift shops and tasting rooms.

When used in the right applications, replacing standard fluorescent troffers—the rectangular fixtures that fit into a dropped-ceiling—with LED troffers can offer significant benefits in the areas of energy savings, operational productivity, and maintenance. Though fluorescent troffers are the most common type of lighting fixture found in US commercial facilities—accounting for 50 percent of existing luminaires—the best LED products outperform their fluorescent equivalents, though at a higher installed cost. Replacement options include installing LED troffers, using LED retrofit kits, or swapping fluorescent tubes for tubular LED products.

When buying LED-based products, ask for performance data from the manufacturer or distributor. It’s also important to check that their reported performance metrics conform to standard test procedures and are verified by accredited third-party laboratories. When comparing LEDs to other options, you should account for cost savings in both energy and maintenance and make sure that the LED solution will provide both the quantity and quality of light that you need for each application to maintain safe, comfortable, and productive working environments. The DesignLights Consortium’s Qualified Products List serves as a great resource for keeping up with LED technologies.

Replace fluorescent lamps. If your facility uses T12 fluorescent lamps, relamping with modern T8 lamps and electronic ballasts can reduce your lighting energy consumption by 35 percent or more. Adding specular reflectors and new lenses can increase these savings and yield short simple payback periods.

Consider high-pressure humidifiers. Humidification is required in barrel storage rooms to keep wooden barrels at their best, and energy-efficient ultrasonic or high-pressure humidifiers can work well in these areas. According to BASE Inc.,high-pressure mechanical humidifiers and ultrasonic humidifiers are great for facilities that require simultaneous humidifying and cooling, but not when heating and humidifying is necessary.

Use high-efficiency boilers. BASE Inc. says that installing high-efficiency boilers could result in up to 6 percent savings of natural gas in hot water energy consumption, with simple payback periods estimated at one to three years.

Preheat boilers with recovered heat. Refrigeration waste heat can be used to preheat boiler water, which also helps cool the refrigerant and saves on both natural gas used for the boiler and condenser fans for the refrigerant. BASE Inc. estimates a savings of 6 to 20 percent on natural gas with simple payback periods ranging from three to six years.

Wastewater can pose environmental hazards and, depending on state pollution laws, may require quite a bit of energy to treat.

Automatic dissolved oxygen control. Aeration involves adding air—in the form of dissolved oxygen—into wastewater to fuel the microorganisms that help degrade any contaminants. Many facilities use manual controls for this process. Instead, automatic dissolved oxygen controls can be installed to proactively monitor the oxygen level in wastewater and shut off once the threshold is achieved. According to BASE Inc.’s Wastewater Energy Program Case Study (PDF) of the LangeTwins Winery, “automated oxygen controls can reduce the aerator energy consumption by approximately 50 percent during the non-crush season.”

Recover biogas. After fermentation and aging, lees (leftover yeast) and marc (grape remains) can produce biogas that can be recovered and burned, either to provide heating or to generate onsite electricity. According to an article in Waste and Biomass Valorization, Energy Recovery and Treatment of Winery Wastes by a Compact Anaerobic Digester, a 40-cubic-meter compact anaerobic digester is optimal for a winery that processes 1,000 tons of grapes per season. Simple payback periods for adding an anaerobic digester can range from six to seven years. See our biogas recovery topic for more information.