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Demand Less, Manage Better

Oct. 6, 2011
The emergence of electrical demand-control technology allows metalcasters to have a more comprehensive understanding of their energy consumption and its effects on their operations and that creates new options for growth.
Powerit Solutions develops electrical demand-control programs for industrial consumers, like the web-based Spara package installed at Eagle Alloys in Muskegon, MI.

Information is power, and for metalcasters aiming to manage their production costs more effectively, information about the power they consume —how much they consume, and when they consume it —is giving them greater control over their operations, and enhancing their bottom lines, which in turn aids their growth prospects. In terms of electrical power, they realize it’s not necessary to choose between higher output and decreasing their energy bills.

Foundries’ electricity consumption is vast, of course, from air compressors to heattreating furnaces, to exhaust scrubbers and innumerable other applications. The most demanding electricity consumers are melting furnaces, and nothing reveals the tension between cost and productivity better than electric melting.

Generally, power is supplied by an electric utility from a local grid, and while the suppliers make considerable revenue from industrial users like foundries they must maintain grid reliability. Electrical surges that may occur when melting aluminum or steel can disrupt grid stability.

“The local grid has a complicated billing procedure,” reported John Workman, who with Mark Fazakerley is coowner of Eagle Alloy Inc., a shell-mold foundry in Muskegon, MI. “There is on-peak and off-peak: On-peak is 11 am to 7 pm, indicating that this is the peak demand period in our state, or our grid, for utilization of electricity; 7 pm to 11 am is considered off-peak.

“But, the energy charges are higher for on-peak than they are for off-peak,” he continued, “and it varies, but the kicker for us is that there is a significant penalty for exceeding our limit for use of energy on-peak, and that could range from $10 to $14 per kilowatt hour, in any 15-min. period between 11 am and 7 pm. So, if we use 4,500 kW in any 15-minute period, multiply that by $10, and that’s quite a penalty — $45,000 — and we end up paying that high rate for the whole billing period.”

Eagle Alloy produces carbon and stainless steel castings weighing anything from just a few pounds up to 800 lb. Melting is done using three induction power supply systems, including: one 1,750-kW Inductotherm VIP® Dual-Trak® Plus unit, one 1,500 -kW Inductotherm VIP® Power-Trak® unit, and one 1,500-kW ABB unit. The three power sources represent 4,750- kW of total electrical demand, and they power six coreless induction melting furnaces, so avoiding penalties as furnaces power-up to complete their melting cycles, all while keeping the entire operation performing smoothly, takes skill, and more.

Workman noted in particular the need to finesse the end of a melt cycle, when there is a critical “25-degree window” for holding the temperature of the liquid metal to ensure the metallurgical quality of the melt.

“We are not a high-volume foundry,” Workman said, explaining why Eagle Alloy’s melting schedule is challenging to manage. “Orders will range from a few pieces (castings) to a thousand pieces, and average probably 50 to 100 pieces in an order. So, we do have a lot of variety of metal specifications and sizes.”

By being flexible and attentive to its buyers, Eagle Alloy has built a reliable customer base, especially over the past two years. “We’re expecting quite a bit more volume,” Workman said.

Managing electrical energy consumption is a critical factor in Eagle Alloy’s success. More than a decade ago the foundry developed a power management program in which an alarm would sound if a furnace exceeded its demand limit. It wasn’t perfect. “It was manually controlled,” Workman recalled. “We had to go and turn down the power level (if the alarm sounded.) There were times when the alarm didn’t work; there were times when we didn’t get to it quickly enough. It doesn’t take long to build up your kW in a 15-min. period.

“What that forced the guys to do was to keep everything at a lower power level, constantly,” he said, an obvious restraint to productivity.

Eagle Alloys melts carbon and stainless with three induction power supply systems representing 4,750- kW of total demand.

In March 2005 Eagle Alloy adopted a new energy management approach and implemented Powerit Solutions’ EMS energy management system. A proprietary control program built into a local platform, it tracked energy consumption and melting cycles, and controlled power usage to avoid exceeding the limit.

“With Powerit we were able to anticipate what the 15-min. period would be, (i.e., the period when the foundry risked exceeding its demand limit) and could virtually start running at 4,500 kW for the first five or 10 minutes. But then, it would hold us back the last five minutes if necessary, whereas before – if we set a limit of 2,000 we could never get over 2,000-kW total, ever, if we reacted to the alarms. With the Powerit EMS we were able to go over that and anticipate the energy utilization in a 15-min period. So, we became more efficient right away.”

In addition, during that temperature- critical period at the end of a melt cycle, Workman said the Powerit system allows Eagle Alloy operators to leave the furnace alone. “Before and after this critical window, we can hold the power back to stay below our set-point and rotate power use with the other pots while charging them,” he said.

In May of this year Eagle Alloy improved its control capability again by updating to Powerit’s latest energy management package, called Spara. It’s an integrated hardware and software package that synchronizes demand reductions by carefully analyzing and managing electrical loads to achieve the desired kW reduction, all while maintaining production volumes.

“The Spara unit has a built in webserver,” according to Powerit’s expert for metalcasting, Dick Winsemius. “It operates with a similar hardware and programming local to the facility, but it’s storing the data on a server and the control application is accessible over the web. So, users can access the data and make adjustments from any location without the need to load and maintain software on each PC.”

Winsemius, who has roughly 30 years of foundry experience, emphasized that Spara is a user-friendly, web-based interface that gives the facilities engineer, plant manager or business owner visibility into a particular furnace or the entire plant remotely through the web – just as they would have at their desktops. More than that, with Spara the overall maintenance demands of the energy management program are simplified. Any program updates are handled centrally, and are universally applied.

The implications of this are farreaching for electric melting, and metalcasting generally. Processes like heat-treating also can realize cost savings by adopting demand-control, Winsemius said.

Earlier this year, Powerit Solutions and Inductotherm Corp. agreed to cooperate to expand energy management for the foundry market: Inductotherm will make Spara available to its induction furnace and control module customers; and both companies will work together to implement energy management strategies and integrate Spara technology in operations.

“We are impressed with Powerit’s ability to manage energy for its many metals customers,” Inductotherm Corp. president and CEO Satyen Prabhu, said in May. “Spara is a proven tool for smart grid connectivity in our field, and we know our customers will be interested in further driving down their energy costs via Powerit’s peak demand control, automated demand response and dynamic pricing features.”

John Workman reported that Spara has allowed Eagle Alloy to fine-tune its kW set-point to operate at a lower level of electricity demand than he had thought possible — 2,400 kW — down from 2,800 kW. The result is more thousands of dollars saved.

A better understanding of electicity demand helps foundries like Eagle Alloys to plan energy consumption more effectively.

Beyond that, Spara is expanding Workman’s opportunities to soon take advantage of an emerging local trend for foundries – demand response. Demand response programs pay end-users like Eagle Alloy to reduce electricity consumption, at times upon demand.

Workman reported that he is looking forward to Eagle Alloys participation in the local utility’s “interruptible supply” arrangement, which is a kind of demand response. In this agreement, the foundry will agree with the utility to decrease its demand set point by a specific kW amount less than the plant’s highest peak kW use during the preceding six hours of operation, when a demand reduction is requested by the utility. “Without Powerit, I would have had no idea what my peak had been in the past six hours,” Workman explained.

More generally, by increasing its energy demand knowledge base, Eagle Alloy is expanding its prospects for success in utility rate negotiations, or in evaluating open-access opportunities. The ability to manage Eagle Alloy’

energy demand is having actual results even now. Soon, the foundry will be melting even higher volumes and expects no loss in efficiency due to the replacement of their current 1,500-kW ABB power supply. The new power supply will be another 1,750-kW Inductotherm VIP® Dual-Trak® Plus unit. With the new unit’s ability to power two furnaces simultaneously for greater production without increasing energy usage, and with the precision power control that Spara makes possible, Eagle Alloy has developed a melting strategy to enhance its position in the industry.

The 70,000-sq. ft. expansion also includes a spent shell-sand reclamation and coating plant, along with equipment additions, in keeping with the additional melting capacity. “This is a record year for Eagle Alloy, and next year we’re expecting a minimum of 40% increase in production,” according to Workman.