Owens Corning saves more than $175,000 a year by reducing electricity consumption by 2.3 million kilowatts

Project

Saving more than $175,000 a year by reducing electricity consumption by 2.3 million kilowatts at Owens Corning’s fiber glass plant in Guelph.

Line of Business

Fibre Glass Manufacturer

Background

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Owens Corning’s plant in Guelph makes tens of thousands of tons of glass fibre annually for customer goods industries. The fiber glass, manufactured as thin thread-like strands, is used to make products such as interior car-door panels, ladder frames, tire cores and cafeteria trays.

The challenge for the Guelph site was to find ways to reduce the electricity costs for the blowers, fans, pumps and compressors required to move, heat and cool the tonnes of glass used to make the glass fibre, says Frank Peel, Owen Corning’s Electrical Engineering Specialist. The process is “very energy intensive,” he adds. 

Early In 2007, the plant began to develop a range of conservation projects to reduce its electricity costs. By the end of 2008, it had completed 10 projects, including two involving lighting replacements, which reduced electricity consumption by more than 2.3 million kilowatt-hours annually. The annual cost saving was more than $175,000.   

Guelph Hydro through the Ontario Power Authority’s Electricity Retrofit Incentive Program (ERIP) has provided more than $17,000 to the Owens Corning’s conservation projects under its prescriptive lighting replacement and customized programs. There is an additional $15,000 committed to proposed projects yet to be completed.

Implementation

As part of a companywide effort to reduce energy costs, Owens Corning facilities around the world received corporate funding in early 2007 to install real-time metering equipment to measure and monitor energy use for its’ major manufacturing processes.

Using its’ new metering system, the 400,000-square-foot Guelph facility launched its’ first energy-efficiency measure – the installation of a variable frequency drive of the furnace stack’s cooling fan.

The metering showed that instead of operating the 75-horsepower blower on the stack at maximum speed, it could be slowed down when not required. The manufacturing process was not affected, but the operating cost was reduced. Because the plant produces glass fibre continuously, electrically driven equipment used for production should never totally shut down, Mr. Peel says. By switching to a variable frequency drive, the fan could be kept running at a lower, less costly, speed until the maximum speed is needed.

After this changeover proved to successfully reduce costs, we looked at other blowers and fans that were running at full speed constantly, but didn’t need to be, and installed variable frequency drives to save money,” he says.

Variable frequency drives have now been installed on the blower units in the plant’s raw materials storage section to move powdered feedstock to the furnace.

Replacing the motors and fans used in its manufacturing processes has reduced the plant’s electricity costs alone by more than $113,000 annually, Mr. Peel says. The simple payback on close to all of the investments was less than three years.

The largest investment was made in the fall of 2008 when nearly more than $175,000 was spent to replace inefficient lighting in the office, plant and warehouse. The annual savings is about $60,000, Mr. Peel says.

In office areas, T12 with magnetic ballasts where replaced with T8 lamps and high efficiency electronic ballasts.  In the plant and warehouse the inefficient 400-watt high-intensity discharge fixtures lamps were replaced with T8s and T5s that have timers and motion sensors.

Mr. Peel estimates the Guelph plant will need to spend another $300,000 to complete the lighting retrofit. “We are only about one-third of the way.”

He says two more energy-efficiency projects will be in place by year’s end, including a new control system for the plant’s chillers, which will reduce electricity consumption by an additional 150 megawatt-hours a year.

Financing

Since 2007, Owens Corning has invested nearly $400,000 in energy conservation projects at the Guelph plant as part of its multi-million dollar investment in energy efficiency at its operations around the world. “Projects are approved for funding on the basis of the best payback,” Mr. Peel says.

At the Guelph plant, paybacks on the energy conservation projects have averaged 2.2 years.

Guelph Hydro, which administers the OPA’s ERIP for its customers, works closely with Owens Corning to develop the applications for the financial incentives.

Results

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Mr. Peel says the 10 energy-efficiency projects now in place at the Guelph plant will reduce electricity consumption by more than 2.3 million kilowatts annually and save about more than $175,000 a year.

These range from a 25 kilowatt reduction by installing a variable frequency drive on the furnace stack cooling blower to 46.5 kilowatt reduction on the cooling fan used in a fiber glass mat production process.

Mr. Peel also noted that the Guelph facility has added to its bottom line by participating in the OPA’s Demand Response 3 program, which pays the company for reducing its electricity demand during periods of peak demand. When the DR3 program is in effect, the Guelph plant adjusts it process to reduce electrical demand by about 10% or 650 kW.

Lessons Learned

Real-time metering equipment is essential in controlling energy costs, Mr. Peel says. “It lets you know where you use energy. And if you make changes you can see where the paybacks are. You don’t know what you’re losing unless you measure it.”

With metering equipment installed, it is straightforward to identify how much electricity is being used and its cost. For example, to determine how much money you can save by installing a variable frequency drive, you measure the electricity used when the blower is operating at its highest speed and then take the measurement when it is operating in the idle mode. You then multiple the net difference by the number of minutes the blower is not running at high speed to determine the potential savings.

“The next challenge is to figure out whether your calculations will save money. It looks great on paper, but when a variable frequency drive costs $10,000, you don’t want to invest in equipment that costs more than the eventual savings,” Mr. Peel says.

It is also important to consider what effect a change in equipment may have on the manufacturing process itself, such as if a fan is slowed down how will it affect the product, Mr. Peel says.

Each change in equipment must be carefully considered, which is one of the main reasons that it can take on average about six months from conception to planning to implementation of energy-efficient measures.