Get Connected!

Supplement - Scrap Metals Supplement

Auto shredder operators can live happily ever after with their local power providers.

January 16, 2012

If you want to obtain power company approval for your auto shredder, propose a shredder system you know will work.

This would appear to be obvious advice, but Quad Plus, based in Joliet, Ill., can cite dozens of examples where yards have been feuding for months with their power companies, simply because they selected a shredder drive without fully researching the power grid or analyzing the situation. As a systems integrator, the company has put in more than 75 shredder drives, helping customers in the U.S. the U.K., Mexico, Canada and Australia connect to the grid.

In that time, the company has discovered some of the "secrets" to successfully navigating the sometimes complex process of obtaining power company approval.

"Don't decide on your shredder drive first and then complain about the headaches your power company is giving you," warns Joseph Crosetto, Quad Plus Recycling Industry Manager.

It's important to look at your request from the power company's perspective, he says. "Yards do things that get them on the bad side of the power company. When you come in with multiple proposals or keep changing your equipment specs, you're asking the power provider to do a tremendous amount of analysis and calculation work.

"You can say, 'It's their job.' But power companies are stretched thin in terms of manpower and resources. Our experience has shown that many of them won't act on a request unless they feel the customer is serious."

Of course the power company wants you to connect to the existing infrastructure and use a lot of energy, especially during off-peak hours, Crosetto says. But, that usage also has to be done in a way that is not going to cause problems for the grid and its existing customers.

As power consumption continues to grow, the investment in power grid infrastructure lags behind, and the power grid is pushed to its limits. For that reason, power companies have tightened their guidelines to make sure new equipment going on the grid will not adversely affect other users.
 

Modeling a Solution
When yards attempt to connect a large shredder motor to the power grid, they question if there is enough capacity on the grid. In reality, that is rarely the problem. The main issue is often voltage fluctuation, or flicker, that disrupts service for other customers. When a motor starts or encounters a load, it will suddenly consume a great deal of power from the line, causing the lights in the area to flicker.

Remember that car shredders are not typical applications. They have a single large motor. The shredder application puts atypical stress on the motor, which does the same to the electrical power being fed to it. The existing distribution lines of most areas are just not set up to handle 9,000-horsepower motors running with a constantly changing load. This requires special attention on the part of the power company when attempting to model a solution.

The power company has a patchwork of transmission lines, substations and distribution lines that have been installed and changed during the last 100 years. They have plans for future expansion but very little money available for infrastructure upgrades. If and when they come up with a way to connect your auto shredder to the grid, it is a given that you will be paying the majority of the cost.

The power company will generally compare the predicted impact of your operation with fairly strict accepted national standards such as IEEE (Institute of Electrical and Electronics Engineers) 1453 for flicker and IEEE 519 for harmonics. A typical, traditional shredder plant cannot meet these standards without being put on a dedicated circuit.
 

Calling on Specialists
A dedicated circuit can be very costly for the shredder operation and is an option you want to try to avoid. The cost of a dedicated service, which involves running a dedicated transmission line to your facility and building a dedicated substation at your site, can run into millions of dollars and can kill a shredder project.

"When I help a customer," Crosetto says, "my goal is to get them connected to the existing distribution lines that run alongside their yard. They connect their shredder drive to the same lines used by other customers. They do this within their construction allowance with little or no out-of-pocket cost to the yard. I have been able to achieve this about 95 percent of the time."

One of the key strategies to achieve that goal is using a power quality specialist working on the customer's behalf. A power quality specialist can perform the same calculations and analysis that the power company would. The specialist can determine the impact of a particular shredder drive on the grid, based on information about the power grid that he or she obtains from the power company. The power quality specialist can then model several solutions on the grid and present the yard with options or recommendations to take to the power provider.

Your power quality specialist can tell you which, if any, of the options will allow you to hook up to the grid using the existing distribution lines in your area. That alone could save a good deal of time and money. They also can tell you if there is a transmission line in your area that would be a good option. You will get more than a yes or no. Your power quality specialist will tell you that 6,000 horsepower is just over the limit but that 5,000 horsepower will work. Or, your specialist will inform you that you have a strong line in the area and can run up to 7,500 horsepower.

It's important to note that most power companies and power company personnel are extremely competent and fair. But they are short-handed. Having a power quality specialist on your team is like having a very affordable insurance policy. The power company may not have the resources to model your proposed system in a timely manner, especially if it is a less common configuration. A good fallback position for the power company is simply to put your auto shredder on a dedicated service. That means the power company will not have to analyze your request in great detail. The power company does not need to risk making a mistake. Future distribution planning will be easier without a shredder drive on a line that's used by other customers.

For those reasons, power company personnel may embrace the idea that the customer can supply a power study. It saves them a lot of work, and it indicates that you are serious about your shredder request. The power company may readily supply the required information about the grid that your specialist needs to create a power study.
 

Receiving Approval
Crosetto explains the Quad Plus process: "Once I receive the data about the local grid from the specialist and the proposed shredder specifications from the manufacturer, I can begin my analysis. The main areas of concern are flicker and harmonics.

"After doing initial calculations, I report back to the customer with preliminary results. We discuss alternative configurations that may improve the power quality or lower costs. The equipment supplier may need to revise quotes at this point.

"Once the customer selects the configuration that best suits their needs, I produce a formal report. After customer review, it is presented to the power company. They sometimes accept the report and sometimes have questions. A second revision of the power study may be required. Occasionally, the power company will call for a face-to-face meeting."

Crosetto continues, "In the end, the power companies have always accepted our reports.

"In a few instances," he explains, "the power company could not refute the calculations but was skeptical that the equipment would act as indicated in the report. In those cases, the company wanted to monitor power quality after startup."

He adds, "I am happy to say that of the many power studies we have done, we have never had a single problem after startup. Several power companies that were initially skeptical have come back and indicated they were shocked that our study was actually conservative. The real-world results were better than predicted."

What else should the prospective auto shredder operator know that would help facilitate connecting to the grid? Crosetto acknowledges that while every situation is unique, a few pointers may apply.

The power company will ask you to fill out a request for service form. The form will not be set up for a shredding facility. Instead, it will be set up as if you are putting in an apartment building. Fill it out as accurately and completely as you can and include a separate document that clearly describes and details your shredder plant electrical requirements, Crosetto suggests.

Make sure you have the right person on your end of the line when you call the power company to make your request, he advises. If a nontechnical person makes the request, he or she will end up speaking to a nontechnical person. However, when a knowledgeable technical person makes the request, he or she will quickly get put through to a planning engineer, who can discuss the situation and supply many of the answers you are seeking in a five-minute call.

Understand that the power company representative usually can use information provided in your power report to produce an estimated power bill for you, if you ask.

Use the information gathered for your power report to help you weigh major decisions and options:

  • Is it better to have 'primary' or 'secondary' metering? These terms identify the owners of the transformers on the site. Primary metering means the customer buys his own transformer and receives a power bill reduction. The power company provides the transformers for secondary metering and builds that cost into future power bills. Rely on your high-voltage design company to work out the best option for your site.
     
  • What is the best kind of shredder drive for my yard? Most traditional shredder plants have only considered AC-WR motors controlled by liquid rheostats. This configuration will almost always require dedicated service. A variety of other shredder drive solutions are available that cause fewer power quality issues on the grid. It is worthwhile to consider these and to factor the cost of power grid infrastructure improvements when making your decision.


The bottom line is that while the process of successfully and cost-effectively connecting your auto shredder to the power grid may not be as easy a process as you had envisioned, putting in the effort up front definitely pays off.

 


This feature was submitted on behalf of Quad Plus, Joliet, Ill. Joe Crosetto, Quad Plus recycling industry manager, can be contacted at 815-724-2242 or at joecrosetto@quadplus.com.