Written by Jim Huston, Manager of System Engineering, W&H Systems
According to The Common Fire Foundation, buildings use 36% of all energy consumed in the US, 65% of electricity, 30% of raw materials and 12% of potable water. Warehousing costs can account for almost 10% of a company’s revenue, with heating and lighting as the two largest energy users. Being able to save money in any of these areas is good for a company’s bottom line.
Warehouse Energy Management Systems
Warehouse and distribution centres can realise great savings by implementing energy management systems. It has been estimated that properly run energy management programs targeting energy efficiency can save five to 20% on energy bills without a significant capital investment. From small to large sites, these savings can represent thousands to hundreds-of-thousands of revenue each year, and many can be achieved with minimal cash outlay. Due to the size of warehouse and distribution centres, even small improvements can have a large positive net effect on the bottom line. In addition to these savings, many utilities offer incentives that can help a business offset the cost to purchase high-efficiency equipment. Also, some US states allow businesses to take a state tax credit that covers a percentage of the cost of investments in energy conservation.
Where do the savings come from when implementing an energy management system? Poor power factor can act as a major energy drain. Inefficient use of supplied power can easily be overlooked because it has few outward signs. There are no blown fuses, tripped circuit breakers, or failed electrical apparatus to alert facility personnel of a problem. Material handling equipment can be made more efficient with the use of high-efficiency motors and an energy management system that shuts parts of the system down automatically when not in use. If a conveyor is required, sensors detect incoming products and automatically start it up again.
By ensuring that equipment is used only when needed, companies can see savings from:
- Improved operating efficiencies
- Less downtime due to undetected equipment problems
- Extended equipment life cycle
- Reduction of power draw (much of your bill is based on the highest peak in a month, even though it may last only a few minutes)
- Lower costs of environmental compliance
Energy-saving Equipment For the Warehouse
The cost for operating equipment in manufacturing facilities and distribution centres is an ongoing cost that requires a substantial amount of electrical power. Companies can reduce electrical demand by upgrading to energy-efficient equipment that utilises high-efficiency motors. Conveyors, sortation units, AS/RS, etc., can be powered by high-efficiency motors or high-efficiency variable-frequency drives.
Many warehouses and distribution facilities are extremely large and house material handling systems that handle varying sizes and weights of containers or products. An individual conveyor system could measure five to six miles. Managing and maintaining this equipment can be a challenge.
Facility managers are always looking for new ways to improve their performance in order to keep equipment running smoothly and efficiently. For example, depending on the complexity of the facility’s conveyor system, it could account for as much as 50% of a facility’s electrical load. Because of these systems’ huge use of electricity, it is a natural target for improving efficiency and saving energy.
One way to reduce power consumption is to retrofit existing conveyor motors with highly efficient, variable-speed motors which feature a “soft-start” that reduces the mechanical shock to the conveyor belts when restarting, significantly cutting maintenance costs. In addition, the “soft start” alleviates the motors’ high draw of electrical current during a restart.
While energy-efficient motors may be more expensive than standard equipment, the true cost of motors is not the purchase price but the cost of daily operation. Over time, the savings provided by an energy-efficient motor can far outweigh its higher purchase price. Energy-efficient motors are also generally more reliable, longer lasting, and put less of a load on electrical distribution circuits.
Saving Space Saves on Utilities
Vertical warehousing helps some companies beat the high cost of land, cut transportation costs, and reduce the operation's environmental impact. By building the warehouse up instead of out, the warehouse has a smaller footprint, and thus saves on costs. A multi-story warehouse allows a company to operate in a dense urban area, rather than locating miles from the population center. Locating the warehouse near the end-customer also saves on transportation costs.
Vertical equipment such as vertical carousels, AS/RS, Conveyors, etc. save on space in the warehouse. Automated storage and retrieval systems, such as Vertical Carousels and Vertical Lift Modules take advantage of unused overhead space to recover 60% to 85% of the floor space typically required by shelving and drawer systems. Improving space utilization in a warehouse saves on the footprint of the building. By reducing the amount of space required for storage and retrieval operations, organisations can construct smaller, more energy efficient buildings, shrinking the construction footprint by up to 15% in some cases, conserving natural resources and reducing maintenance costs. This improved space utilisation helps reduce energy costs, which helps reduce an organisation's overall carbon footprint.
Lighting & Other Energy Saving Tips
To lessen the load, remove one or two bulbs in lighting fixtures that take four or more bulbs. Lighting each bulb in the fixture isn't necessary where lighting isn't critical. Use timers or sensors so that lights turn off when no one is around that area of the warehouse. High-intensity discharge (HID) light sources, such as metal halide and high-pressure sodium lamps, have long dominated the market for lighting indoor spaces with high ceilings, but today other technologies have proven more efficient under many common situations. For aisles, fluorescent fixtures (high-performance T8 lamps and ballasts) work best for heights of less than 20 feet (6 meters). For locations requiring greater clearance, and for many high-bay areas, fluorescent lights (high-performance T8 lamps or high-output T5 lamps) are usually the most efficient choice. LED lighting is the most efficient and has dropped enough in price to be cost-effective for many warehouses.
Painting walls white and installing windows to introduce natural light will improve light levels while reducing energy, provided the windows use thermal or double-paned glass.
The HVAC system is a huge drain on energy in a warehouse. If the warehouse is unoccupied much of the time, evaluate the level of heating and air conditioning really necessary to make the environment comfortable or store the company’s products. Oversized ceiling fans may be able to reduce temperatures in the facility. Regular maintenance, such as changing filters, is important for good operation and to avoid energy waste.
Dock shelters, which enclose the entire back of a truck are more energy-efficient than roll-up dock doors because they reduce outside air exchange. Dock shelters most likely won’t be found in warehouse facilities built on spec because they’re more expensive than typical loading docks. Regularly checking and repairing gaps in the seals around loading-dock doors is a quick energy saver.
A warehouse with older insulation is losing energy to the environment. Traditional batt insulation can be replaced by more efficient spray foam or loose fill. Spray foam insulation is the most expensive but is twice as efficient as batt. Loose fill is a middle alternative that is easy to install in existing spaces and still provides superior insulation.
Another potential opportunity is working with your local utility company on a potential rebate for a reduced peak-load demand. Some utility companies offer these incentives because it minimises the load on power supplied by the local power plant. Utility companies policies on these types of programs may vary from state to state so be sure to inquire about any potential programs that may exist.
As SKU proliferation continues, with new products and packages demanding more space in the warehouse, organizing and finding room for everything in can be a challenge.
Implementing sustainable practices throughout a warehouse will not only save money for the organisation, but will increase customer goodwill. Don’t think of sustainability in terms of costs; think of it as an investment resulting in revenue savings—a better bottom line and a better image that win the respect of your customers and your community.