Tennessee Valley Authority
Frequently Asked Questions
Why are only solar and wind systems accepted as qualified systems?
How much will the generation system cost?
Where can I buy my system? Is there a list of qualified vendors?
How long am I guaranteed credits/payments for the power I generate?
How is the program different for demand-metered customers (less than 50 kW)
Why are only solar and wind systems accepted as qualified systems?
All of the generation that is purchased through the GPS Generation Partners demonstration will be used for TVA’s renewable energy program, Green Power Switch. This means the generation must meet the same accreditation standards that are required of Green Power Switch. Green Power Switch consists of energy from solar, wind and methane gas, but accreditation standards require a certain amount of each generation source. At the present time, GPS does not need any more methane gas, but is trying to focus on increasing the amount of solar and wind.
How much will the generation system cost?
For a typical size photovoltaic system, 1.5 kilowatts to 2 kilowatts, you can expect to pay on average $8 - $10 per watt for parts and installation. A typical small wind turbine system averages $2 to $4 per watt for equipment, plus the cost of installation. There are several factors that must be taken into consideration when pricing either solar or wind systems. These consumer guides offer more detailed information (PDF files, require Adobe Acrobat Reader):
Where can I buy my system? Is there a list of qualified vendors?
System sizing tips, cost estimations, supplier/installer information, and related information can be researched at the following Web sites:
North American Board of Certified Energy Practitioners
NABCEP is a volunteer board working to develop national voluntary standards and certifications for renewable energy professionals, beginning with solar electric installers. Look for the listings of these certified installers under the Resources link on the Web site.
American Solar Energy Society
Center for Renewable Energy and Sustainable Technology - Click on Solar
Consumer Energy Council of America, Distributed Energy Forum
U.S. Department of Energy, Energy Efficiency and Renewable Energy
U.S. Department of Energy, Energy Efficiency and Renewable Energy Solar Technology Division
Florida Solar Energy Center - click on Photovoltaics and/or Solar Energy
Tennessee Solar Energy Association
National Association of State Energy Officials
North Carolina Solar Center
National Renewable Energy Laboratory
Solar Electric Power Association
Solar Energy Industries Association (202-383-21600)
Note: The listings provided here are for informational purposes only. The listing of any group or organization is not to be considered as an endorsement by TVA. TVA assumes no responsibility for actions taken by the mentioned groups or organizations.
How long am I guaranteed credits/payments for the power I generate?
The credit/payment schedule for qualifying systems remains valid for 10 years upon the effective date of the signed contract with the local participating power distributor.
How safe is my system?
All interconnection and safety equipment must be listed by Underwriter Laboratory (UL) or Electrical Testing Laboratories (ETL) for grid-connected terrestrial power systems. In addition, all systems must be manufactured and installed in compliance with the National Electric Code (NEC). Systems must be permitted and certified by a licensed electrician along with passing all applicable code inspections.
Having your system meet these national standards means that your system is very safe. In addition to these national standards, GPS Generation Partners requires an outside lockable disconnect device that provides the additional security and peace of mind necessary for the demonstration to succeed. The lockable disconnect device must be accessible by personnel from the local power distributor, who have the ability and authority to lock out the power from the grid via the disconnect device. For more information about safety, see the following sites:
- National Fire Protection Association
- Underwriters Laboratories
- Institute of Electrical and Electronics Engineers
- Solar Electric Power Association
How is the program different for demand-metered customers (greater than 50 kW)?
Many of the requirements for demand-metered customers are the same as for the residential and small commercial customers, but there are some key differences:
- Demand-metered customers are limited to installing photovoltaic (solar) systems only.
- Due to the higher installation costs associated with these systems, the credits paid are $0.20 per kilowatt-hour.
- Due to more complex metering, participants must review plans and agree on the metering protocol with the power distributor prior to installation.
- The power distributor will bill the participant for the equipment cost of the generation meter due to wide variation in metering arrangements. The power distributor may also charge the participant for remote meter reading, if necessary.
- The system size limit of 500 watts to 50 kilowatts is still applicable, but larger systems may be considered on a case-by-case basis.
The following distributors offer the demand-metered contract:
- Appalachian Electric Cooperative
- Cleveland Utilities
- Florence Utilities
- Greeneville Power and Light
- Harriman Utility Board
- Huntsville Utilities
- Johnson City Power Board
- Knoxville Utilities Board
- Lafollette Utilities Board
- Memphis Light, Gas and Water
- Murfreesboro Electric Department
- Nashville Electric Service
- Oak Ridge Electric Department
- Powell Valley Electric Cooperative
- Sheffield Utilities