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Questions & Answers

Frequently Asked Questions with Co-generation and or Interconnecting Distributed Generation, Specifically Wind Energy

General Wind Energy Questions:

What are the benefits of installing a wind turbine at my home or business?
Wind energy has both environmental and economic benefits. It is emissions-free, and it is renewable. The fuel (the wind) is free, and will never fluctuate in cost.

However, wind is a long-term investment, and the amount of electricity it produces is very site specific. Before purchasing a wind turbine, you should first evaluate your site – assessing wind speed, understanding the site topography, identifying any permitting restrictions that may apply. All these things will determine how much power you can generate.

If I am looking a purchasing a wind turbine then what should I know before hand?
You need to know several things.

  • First, what average wind speed can you expect at your site. Ideally, you should erect an anemometer to measure the wind speed. If erecting an anemometer is not practical, go to the web site of the Iowa Energy Center at http://www.iowaenergycenter.org. This site is an excellent source of reliable information.
    • Click on Renewable Energy, then on Wind. If you click on Wind Assessment and Calculator, agree to their conditions, and enter the data for your site, you will get information such as average wind speed, air density, average wind power density, and estimated output for each month of the year.
  • Secondly, is there any building code or zoning ordinance that would restrict the location or height of the wind turbine tower. Even if there are no such restrictions, it is general wise to set the turbine back at least by the height of the tallest point on the turbine from all buildings, electrical lines, roads, and property lines.

What questions should I ask a dealer or company that wants to sell me a wind turbine?
There are a few questions you will want to ask a wind turbine representative that wants to sell you their product.
Performance –

  • How long has the manufacturer been producing small wind turbines?
  • How long has the make and model been on the market?
  • Can you get the names and contact information of other people who have purchased his unit?
  • Is the wind speed at your site above the minimum speed required for the turbine to start generating power?
  • Has the turbine’s overspeed protection been demonstrated to be effective?
  • What noise level (in decibels) does the unit generate at what distances?

Components –

  • Do you need to buy the tower, electronics, and other components separately or are they included in the price?
  • Do all the components have UL approval?
  • Is there sufficient lightning protection (wind turbines make great lightning rods.)?
  • Is there a warranty?
    • Does the warranty cover a reasonable period of time?
    • Does the warranty cover the cost of parts and labor?
    • Does it include the cost of a crane if it is needed?

Services –

  • What services are offered with the turbine?
  • Will the manufacturer install it?
    • If not, will it provide installation assistance?
  • Is there a maintenance package that you can purchase?
  • Does the manufacturer offer technical support?

Installation and Maintenance –

  • Is it feasible for you to install the turbine and all components?
  • If you need to hire someone to install it, how much will that cost?
  • What is the routine maintenance schedule for the unit you are considering purchasing?
  • How often do major components fail?

Documentation –

  • Can you browse the user manual before purchasing?
  • How easy is it to understand?

What will T.I.P. Rural Electric Cooperative require of me if I want to connect my wind turbine to the distribution lines?
Permission to interconnect with the Cooperative or CIPCO electric system is contingent upon the following conditions:

  • The member-consumer shall comply with acceptable standards for interconnection, safety, and operating reliability. Acceptable standards include the most current revisions of the following, as adopted in the Iowa Administrative Code section 199-15.10(1), in order to be eligible for interconnection to the Cooperative or CIPCO electric system:
    • Standards for Interconnecting Distributed Resources with Electric Power Systems, ANSI/IEEE Standard 1547-2003. For guidance in applying IEEE Standard 1547, the Cooperative may refer to:
      • IEEE Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems - IEEE Standard 519-1992; and
      • IEC/TR3 61000-3-7 Assessment of emission limits for fluctuating loads in MV and HV power systems.
    • Iowa Electrical Safety Code, as defined in 199—Chapter 25.
    • National Electrical Code, ANSI/NFPA 70 2008.
  • The member-consumer facility shall meet the standards for interconnection as set forth in the Model Interconnection Agreements and the attachments thereto. Said Model Agreements are attached hereto as Appendices B and E.
  • The member-consumer shall agree to indemnify and defend the Cooperative and CIPCO and their representatives against liability for any injuries or damages caused by the operation of the member-consumer's equipment or by any failure of the member-consumer to maintain such equipment in satisfactory or safe operating condition. The member-consumer will arrange for and maintain liability insurance with limits of not less than those set forth in the attached appendices, with the insurance requirements varying depending upon the size of the interconnecting generator. Failure to maintain required insurance or proof of financial responsibility shall be cause for disconnection. The Cooperative and CIPCO shall be named as additional insureds, to the extent specified in the attached appendices.
  • The member-consumer shall reimburse the Cooperative or CIPCO for costs incurred by the Cooperative or CIPCO for all costs of connection, switching, metering, transmission, distribution, safety provisions and administrative costs incurred by the Cooperative or CIPCO directly related to the installation and maintenance of the physical facilities necessary to permit interconnected operations with a qualifying facility (or qualifying alternate energy production facilities, or qualifying small hydro facilities), to the extent the costs are in excess of the corresponding costs which the Cooperative or CIPCO would have incurred if it had not engaged in interconnected operations, but instead generated an equivalent amount of electric energy itself or purchased an equivalent amount of electric energy or capacity from other sources. Interconnection costs do not include any costs included in the calculation of avoided costs.
  • The member-consumer shall agree to discontinue sales to Cooperative/CIPCO when, due to operational circumstances, purchases from the member-consumer will result in CIPCO costs greater than those which CIPCO would incur if it did not make such purchases, but instead generated an equivalent amount of energy, provided, however, that CIPCO shall notify the member-consumer within a reasonable amount of time to allow the member-consumer to cease the delivery of energy.
  • The applicant and the Cooperative shall execute the applicable Model Interconnection Agreement prior to interconnection. In the event the applicant desires to sell any excess output from its facility to the Cooperative and/or CIPCO, a separate power purchase agreement shall be required for all interconnections except Level 1. For Level 1 interconnections, the terms of purchase are set out on Attachment 2 to the Level 1 Standard Application Form and Interconnection Agreement.
  • The member-consumer shall permit Cooperative or CIPCO representatives to enter upon member-consumer's property at any reasonable time for the purpose of inspecting or testing member-consumer's equipment, facilities or apparatus and the accuracy of the Cooperative or CIPCO’s metering equipment, but such inspections shall not relieve the member-consumer of the obligation to maintain the member-consumer's facilities in satisfactory operating conditions.
    The Cooperative or CIPCO may charge the direct expense of such inspecting or testing of the member-consumer’s equipment, facilities or apparatus to the member-consumer, unless the member-consumer can demonstrate the inspecting and testing was not necessary. The member-consumer shall adopt a program of inspection of the generator and its appurtenances and the interconnection equipment in order to determine necessity for replacement and repair.
  • The member-consumer shall be responsible for the costs of installation and maintenance of any necessary power factor correction capacitors. Member-consumers with a distributed generation facility larger than or equal to 1 MVA shall design their distributed generation facilities to maintain a power factor at the point of interconnection between .95 lagging and .95 leading at all times. Member-consumers with a distributed generation facility smaller than 1 MVA shall design their distributed generation facility to maintain a power factor at the point of interconnection between .90 lagging and .90 leading at all times.
  • The member-consumer’s electric generating equipment shall be designed; operated and maintained in such a manner that it does not adversely affect the Cooperative’s or CIPCO’s system or their service to their other members.

You will need to determine which Level of interconnection you are applying for.

Level 1:
Level 1 Application and Agreement shall be used for all interconnection requests to connect a distributed generation facility when:

  • The applicant has filed a Level 1 application; and
  • The distributed generation facility has a nameplate capacity rating of 10 kVA or less; and
  • The distributed generation facility is inverter-based; and
  • The member-consumer interconnection equipment proposed for the distributed generation facility is lab-certified; and
  • No construction of facilities by the cooperative or CIPCO shall be required to accommodate the distributed generation facility.

           To remain in Level 1, the following screens must be met:

  • For interconnection to a radial distribution circuit, the total of all distributed generation connected may not exceed 15% of the maximum load normally supplied by the circuit
  • For interconnection on a single-phase shared secondary line, the aggregate generation capacity on the line will not exceed 20 kVA
  • When the distributed generation facility is single-phase and proposes to interconnect on a center tap neutral of a 240 volt service, its addition may not create an imbalance between the 2 sides of the 240 volt service of more than 20% of nameplate rating of the service transformer
  • Utility shall not be required to construct any facilities on its own system to accommodate the distributed generation facility's interconnection
  • For interconnection to a spot network, distributed generation will use protective equipment to ensure power imported from utility to the network will remain above 1% of the network's maximum load over the last year

Level 2:
Level 2 Application and Agreement shall be used for evaluating interconnection requests when:

  • The applicant has filed a Level 2 application; and
  • The nameplate capacity rating is 150 kVA or less; and
  • The interconnection equipment proposed for the distributed generation facility is lab-certified; and
  • The proposed interconnection is to a radial distribution circuit or a spot network limited to serving one member-consumer; and
  • No construction of facilities by the cooperative or CIPCO shall be required to accommodate the distributed generation facility, other than minor modifications permitted by the Cooperative.

           To remain in Level 2, the following screens must be met:

  • For interconnection to a radial distribution circuit, the total of all distributed generation connected may not exceed 15% of the maximum load normally supplied by the circuit
  • The proposed distributed generation, in aggregation with other distributed generation on the distribution circuit, may not contribute more than 10% to the circuit's maximum fault current at the point on the primary line nearest the point of interconnection
  • The proposed distributed generation, in aggregation with other distributed generation on the circuit, shall not cause any electric utility distribution devices to be exposed to fault currents exceeding 90% of their short-circuit interrupting capability
  • When a distributed generation facility is to be connected to a 3-phase, 3 wire primary line, a 3-phase or single phase generator shall be connected phase-to-phase
  • When a distributed generation facility is to be connected to a 3-phase, 4 wire primary line, a 3-phase or single phase generator shall be connected line-to-neutral and shall be grounded
  • For interconnection on a single-phase shared secondary line, the aggregate generation capacity on the line will not exceed 20 kVA
  • When the distributed generation facility is single-phase and proposes to interconnect on a center tap neutral of a 240 volt service, its addition may not create an imbalance between the 2 sides of the 240 volt service of more than 20% of nameplate rating of the service transformer
  • A distributed generation facility, in aggregate with other distributed generation facilities interconnected to the distribution side of a substation transformer feeding the circuit where the facility proposed to interconnect, may not exceed 10 MVA in an area where there are transient stability limitations
  • Utility shall not be required to construct any facilities on its own system to accommodate the distributed generation facility's interconnection, except minor modifications following agreed upon additional review
  • For interconnection to a spot network, distributed generation will use protective equipment to ensure power imported from utility to the network will remain above 1% of the network's maximum load over the last year.

Level 3
Level 3 Application and Agreement shall be used for evaluating interconnection requests to area networks and radial distribution circuits where power will not be exported based on the following criteria.

  • For interconnection requests to the load side of an area network, the following criteria shall be satisfied to qualify for a Level 3 expedited review:
    • The applicant has filed a Level 3 application; and
    • The nameplate capacity rating of the distributed generation facility is 50 kVA or less; and
    • The proposed distributed generation facility uses a lab-certified inverter-based equipment package; and
    • The distributed generation facility will use reverse power relays or other protection functions that prevent the export of power into the area network; and
    • The aggregate of all generation on the area network does not exceed the lower of 5 percent of an area network’s maximum load or 50 kVA; and
    • No construction of facilities by the cooperative or CIPCO shall be required to accommodate the distributed generation facility.
  • For interconnection requests to a radial distribution circuit, the following criteria shall be satisfied to qualify for a Level 3 expedited review:
    • The applicant has filed a Level 3 application; and
    • The aggregated total of the nameplate capacity ratings of all of the generators on the circuit, including the proposed distributed generation facility, is less than 150 kVA; and
    • The distributed generation facility will use reverse power relays or other protection functions that prevent power flow onto the electric distribution system; and
    • The distributed generation facility is not served by a shared transformer; and
    • No construction of facilities by the cooperative or CIPCO on their own systems shall be required to accommodate the distributed generation facility.

           To remain in Level 3, the following screens must be met:
Utilize the same screens as are applicable for level 2 interconnections; except for the one prohibiting the total distributed generation connected to a radial distribution circuit from exceeding 15% of the maximum load normally supplied by the circuit

Level 4
Level 4 Application and Agreement shall be used for evaluating interconnection requests when:

  • The applicant has filed a Level 4 application; and
  • The nameplate capacity rating of the small generation facility is 10 MVA or less; and
  • Not all of the interconnection equipment or distributed generation facilities being used for the application are lab-certified, or Applicant is unable to comply with level 1 through 3 screens.

Please read them carefully and contact us with any questions that you may have.

The Cost of Extending our Lines –
If you want to connect your wind turbine to our lines, the first thing that we would need to do is extend our distribution lines to your unit. We will charge you our cost, but in general in costs $30,000 per mile of line to extend a single-phase circuit and $50,000 per mile to extend a three-phase circuit.

Cost of the Interconnection Point –
The point of interconnection will require a meter that has the capability to record power flowing from us to you and a separate channel to record power flowing to you to us. It must have anautomatic disconnection that disconnects your wind turbine anytime we suffer an outage on your circuit. This prevents power from flowing onto our system when our line personnel think that the lines are not energized. We will also require you to have a switch that provides a visible break or opening and is capable of being padlocked in the open position. This is necessary so that our line personnel can isolate your wind turbine when they are working on the lines and know that only they can reconnect your turbine to our system.

A Liability Insurance Policy – The interconnection member-consumer shall provide the Cooperative with proof that it has a current homeowner’s insurance policy or other general liability policy. The interconnection member-consumer agrees to provide the Cooperative with at least 30 calendar days’ advance written notice of cancellation, reduction in limits, or non-renewal of any insurance policy required by this Agreement and may be required to show proof of insurance on an annual basis.

Do you offer “net metering”?
Yes, we do – on wind turbines that are less than 100 KW. We meter the amount of power that flows from our lines into your home, farm, or business and separately the power that flows from your equipment onto our lines. If you “sell” us more electricity than you buy from us, we pay you our “avoided cost” for any kilowatt-hours generated in the month.

What do you mean by “avoided cost”?
Avoided Cost is a term that is found in federal law. It means that we have to pay a Qualifying Facility an amount for energy that we purchase from it at a rate equal to what we could purchase that power from the open market. Since the Central Iowa Power Cooperative (CIPCO) provides us with all of our power under a long term contact, our avoided cost is the same as CIPCO’s avoided cost. That cost is generally adjusted each year.

What if I want to install a wind turbine with a rated capacity greater than 100 KW?
We would negotiate an agreement for such larger wind turbines on a case-by-case basis.

Who else can I get help and advice from?
We would recommend that you contact the Iowa Energy Center. It is part of Iowa State University and is funded in part by a small charge on the electricity that electric utilities sell. In addition to information, it has a loan program that can help finance the purchase of wind turbines. Its address is:
Iowa Energy Center
2521 Elwood Drive
Suite 124
Ames, Iowa 50010-8229
Phone: 515-294-8819
Fax: 515-294-9912
E-mail: iec@iastate.edu
Website: http://www.iowaenergycenter.org

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