Surveying the plant-scape for ripe opportunities to save energy, engineers usually find that big boilers or big process heat sources are the low-hanging fruit that will pay the big bucks. Now, at a time when many capital projects are on the back burner, those big heat and steam recovery projects may have to wait.
While a few giant assets can gobble up a large portion of a plant’s energy usage, there are dozens, maybe hundreds, of motors that can’t be bundled into a single project. But they still should be considered and even managed over time in a systematic manner with repair/replace guidelines, purchasing policies based on life-cycle costing and predictive and preventive maintenance planning.
Motors may be overlooked in capital project plans — which may well be on hold while the recession and credit crunch continue — but motors can add up to make a big dent in a plant’s overall efficiency profile.
- Electric motors account for nearly two-thirds of energy used in industrial settings, according to the Dept. of Energy (DOE).
- In keeping with the DOE estimate across industries, motor use in the food industry accounts for 60-70 percent of the typical plant’s total energy costs, according to a consensus of industry experts.
- The purchase price of a motor accounts for a fraction of its actual cost; at least 97 percent of the costs are incurred by electrical consumption over the motor’s service life.
It’s not just inevitable that food plants will gravitate toward higher-efficiency motors; soon, the law will require motor manufacturers to meet higher efficiency standards in the motors they offer.
Law to bump-up efficiency
The Energy Independence and Security Act of 2007 is a federal law that will take effect Dec. 19, 2010 to address a broad range of efficiency measures. Title III Section 313 of the act covers Electric Motor Efficiency Standards. When the law takes effect, it won’t mandate any immediate changes by end users.
The act specifies changes to most three-phase AC induction motors, 600 V or less, ranging in horsepower from 1 to 500 hp, which will fall into one of three groups when the law takes effect:
Looking to the Future
- Motors of 1-200 hp that were covered under a previous law, the 1992 Energy Policy Act (EPAct, enacted in 1997), must be manufactured to the highest level: the NEMA Premium standard of the National Electrical Manufacturers Assn. (NEMA).
- Motors 1-200 hp that were not covered by EPAct must be manufactured to the Energy Efficient designation that covered general purpose motors under EPAct.
- Motors 201-500 hp also must be manufactured to the above Energy Efficient standard.
In short, the act will bump-up the efficiency of motors by law instead of by choice. Some of the things the law will not affect include fractional-horsepower motors, two-phase motors (more common in small machinery) and DC motors, which generally have been eclipsed in plants by lower-maintenance AC motors mated to variable speed drives.
That leaves plenty of room to mandate better AC motors in production; heating, ventilation and air conditioning systems; and elsewhere around the facility — all of which eventually will get more efficient replacements.
“The law doesn’t force anyone to replace their motors. They can maintain their existing motors as long as they like,” says William Hoyt, industry director for NEMA. “But one thing they cannot do is repair a low-efficiency motor to make it a high-efficiency motor.”
So at some point, perhaps long after the supply chain is depleted of older-generation motors, the only available replacement motors will have been manufactured to higher standards.
Leading and green-leaning companies already opt for NEMA Premium-rated motors (http://www.nema.org/gov/energy/efficiency/premium), which bowed in 2003 to raise the bar on motor efficiency. Among their operational benefits, they meet tighter manufacturing tolerances for greater reliability and run cooler for greater overall energy efficiency.
Not surprisingly, progress has its price. When plants decide a motor can’t be rewound or refurbished, “They’ll be buying better products at a higher price,” says Robert Kindred, technical services manager at Toshiba International’s Industrial Division (www.toshiba.com/ind), Houston. Which is what happened 12 years ago when EPAct became law.
In the case of NEMA Premium, the price premium varies from 25 percent on a small motor costing $200 to 5 percent in the hundreds-of-horsepower range — a minor increase considering that “motors are usually a very minor component in much larger systems,” Kindred says. “People shouldn’t forget that this is not about motors alone. If people really want to save money, they need to look at total system efficiency.”
A DOE study conducted 10 years ago showed the average efficiency for a 200-hp motor was 93.5 percent. At that standard, a 200-hp compressor motor costs $139,785 to run 24/7, year-round, based on an assumed average electrical cost to the industrial user of 10 cents per kilowatt hour.
The same motor meeting EPAct energy efficiency levels would cost $137,578, for annual savings of $2,207, based solely on a 1.5 percent efficiency increase in the EPAct Energy Efficient designation from 93.5 percent efficiency to 95 percent.
Furthermore, if the replacement motor was chosen from the next step up, to NEMA Premium, it would be 96.2 percent efficient. Using the above assumptions, the motor would cost $135,862 to operate, saving $3,923 over the original motor, according to John Malinowski, product manager for AC and DC motors at Baldor Electric (www.baldor.com), Fort Smith, Ark.
Those savings will likely exceed this example in light of rising energy prices, lower maintenance costs and steadily increasing service-life for motors, currently “around 28 years,” Malinowski says. He adds: “For the sake of this conservative example, let’s say that motor lasts 20 years — that’s still $78,460 savings for a NEMA Premium motor over the original motor.”
And for that reason, he believes “everybody” should embrace the use of higher efficiency standards such as NEMA Premium. “It’s green, you save money and the numbers are there.”
NEMA Premium motors would save 5,800 gigawatts of electricity if used to the fullest, NEMA reports, preventing the release of nearly 80 million metric tons of carbon dioxide into the atmosphere in a decade. That’s the equivalent of taking 16 million cars off the road.
Food & beverage plant managers already are looking at the motor requirements in the Energy Independence and Security Act of 2007, which will take effect in 2010.
NOTE TO PURCHASING
A lack of awareness, visibility or even corporate culture can lead to short-sighted purchasing decisions. Sometimes, budgets or even perceptions can prevent maintenance and purchasing departments from working well together. For example, when a motor fails, many maintenance departments will opt to rewind and repair it years beyond the point of cost-efficiency because “they feel it’s just not worth the trouble of getting capital sign-off on a new motor,” says John Malinowski, product manager-AC & DC motors at Baldor Electric Co.
Then there are the purchasing departments that are rewarded for spending less rather than saving more. Spending $2,000 extra for a higher-efficiency motor can save $3,923.
When a plant’s electric bill is handled by a different location, and purchasing doesn’t have access to the cost via integrated reports, the purchasing department may “never realize what they’re spending, or saving,” Malinowski says. “We have to change the paradigm.”
More Efficient Chips, Cheese and Beans
No, those aren’t leftovers from Super Bowl Sunday. The following trio of companies exemplifies how motors play a sometimes hidden role in the larger context of energy savings:
Frito-Lay (www.fritolay.com), PepsiCo’s green-leaning snack division based in Plano, Texas, reportedly is replacing old motors with NEMA Premium in higher energy markets in the northern U.S. while maintaining motors for a longer period in the South, where energy is cheaper. The company’s stated goal in 1999 was to reduce electricity consumption by 25 percent, which has been within low single-digit reach in recent years. Al Halvorsen, director of environmental sustainability, in a university presentation late last year, said the company saved $55 million on water and energy last year alone across 39 manufacturing plants and 195 distribution centers.
Davisco Foods (www.daviscofoods.com), brought together personnel at its LeSueur, Minn., food ingredients plant as part of its work with DOE’s Save Energy Now program (www.eere.energy.gov/industry/saveenergynow/index.html). In one exercise, Ron Wroblewski, the designated DOE energy expert and president of Productive Energy Solutions, Madison, Wis., helped plant employees identify at least one case where a “larger motor that had been ordered for one [spray dryer’s] fan was probably unnecessary,” according to his DOE report.
Bush Brothers & Co. (www.bushbeans.com), at its flagship plant in Chestnut Hill, Tenn., underwent a major renovation, in which new motors and associated assets were installed. “We chose products based on what we felt was a good TCO [total cost of ownership] strategy,” says Michael Rife, the plant’s maintenance planner and buyer.