SOLAR TODAY - March/April 2012

One missing piece remains: electrical testing and listing of small wind turbines for code compliance. UL is developing new electrical safety standards to address this issue.

S WCC Consumer Label

standard for reporting turbine energy and sound performance, and provides consumers with performance data to help them make informed purchasing decisions.

AWEA is recognized by the American National Standards Institute (ANSI) as an accredited standards developer. The AWEA standard was developed in a regimented ANSI process for “voluntary consensus standards,” which requires participation from representatives of manufacturers, technical experts, public-sector agencies and consumers.

The AWEA standard is based upon three international standards issued by the International Electrotechnical Commission (IEC): • IEC 61400-2: Design requirements for small wind turbines;

• IEC 61400-11: Wind turbine generator systems – Acoustic noise measurement techniques; and • IEC 61400-12-1: Wind turbines – Power performance measurements of electricity producing wind turbines.

In addition, the AWEA standard is similar to the British Wind Energy Association (BWEA) standard issued by RenewableUK and used by the Microgeneration Certification Scheme.

SWCC issues labels showing the rated annual energy output, rated power and rated sound level for each certified turbine. The labels also confirm that fully certified turbines meet durability and safety requirements. As turbines are certified, SWCC’s web directory includes their power curves, annual energy performance curves, measured sound-pressure levels and other technical information.

swcc issues easy-to-understand labels showing the rated annual energy output, rated power and rated sound level for each certified turbine. the labels also confirm that fully certified turbines meet durability and safety requirements.

Reports from testing organizations accredited to ISO/IEC Standard 17025, such as the National Renewable Energy Laboratory, require minimal scrutiny from SWCC. Test reports from non-accredited organizations require a higher level of scrutiny to independently verify the competence of the organization and the quality of the test reports and that the testing complies with the AWEA standard. SWCC performs onsite evaluations of all non-accredited test organizations.

SWCC maintains a list of test organizations that intend to test small wind turbines for the North American market. The list may not be all-inclusive and is not an endorsement of any test organization, only a resource intended to help manufacturers find a test organization.

SWCC certification takes approximately two to four months from the time SWCC receives test reports and a complete application, depending on the quality of the test reports and the issue resolution required. The structural analysis of the wind turbine can be performed in parallel with field-testing, but SWCC recommends that this analysis be performed early in the certification process, before field-testing begins.

Once its Certification Commission grants certification, SWCC issues a certificate and posts technical information about the turbine model on its website. While applications are pending, SWCC lists the applicant’s name and turbine model, the date the applicant’s contract was executed, the date the turbine testing began and the date the applicant submitted reports. The applicant can choose to have its name, model and status remain confidential while it pursues certification.

Milestones in SWCC’s process include — • Under Contract: Indicates that the applicant has executed a certification agreement with SWCC.

• Under Test: Indicates that the small wind turbine has been installed at the test site, commissioned, instrumented and is collecting data.

• Reports Submitted: Indicates that the applicant has submitted a complete test and analysis report to the SWCC with a certification application.

• Conditional Temporary Certification: Indicates that SWCC has granted a time-limited certification for a small wind turbine tested and certified to the IEC 61400 series of standards or the BWEA Standard by a certification body that has signed an agreement with the SWCC.

Process depends on Quality testing

Eligible turbines are newly manufactured electricity-producing wind turbines with a swept area up to 200 square meters ( 2,150 square feet). That corresponds to a rotor diameter of about 16 meters ( 52 feet). Depending on the turbine design, this maximum size is a turbine producing about 50−65 kilowatts. Both horizontal- and ver-tical-axis turbines are eligible for certification.

SWCC does not test turbines; it accepts reports from testing organizations. Testing a small wind turbine to the requirements of the AWEA standard takes at least six months due to durability testing requirements. Depending on the wind regime in which the test facility is located, the wind turbine design and issues that arise, testing and reporting may take one year or more.