The IREC Interview: Small Wind Expert Brent Summerville

Brent Summerville is Technical Director of the Small Wind Certification Council.  He is a licensed professional engineer with a BS in Mechanical Engineering from North Carolina State University and a Masters in Appropriate Technology from Appalachian State University (ASU). He started his career testing small wind turbines while serving as the manager of the ASU Small Wind Research & Demonstration Site on Beech Mountain.

IREC: You’ve been involved with Small Wind for a while now.  Tell us how you first got involved and what drew you into the field.

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Summerville repairing the Whisper 500 on Beech Mountain

BS: The day I graduated from the Mechanical Engineering program at North Carolina State, I picked up a copy of Home Power magazine at a friend’s house and I was immediately hooked on renewable energy. Soon after, I had a ‘take your bedroom off the grid’ system that travelled with me. After working as a Manufacturing Engineer for nearly a decade, I finally decided to pursue this interest by going through the Appropriate Technology graduate program at Appalachian State University. I was open to all RE technologies and the program allowed me to design and install solar water heating, PV, microhydro and small wind systems. ASU had a DOE grant at the time to set up their Small Wind Research & Demonstration facility on Beech Mountain. I ran the Beech Mountain site as a graduate student and employee, where I spent several years installing, repairing and testing small wind turbines. We also led many successful hands-on workshops at the site. This experience at ASU eventually led to my current position at SWCC.

IREC: In your work as the Technical Director of SWCC, you have a unique opportunity to see the changes in the field.  What, in your opinion, are the most important developments in small wind right now?

BS: After working at an energetic, demanding small wind test site, I realized early on that designing a durable, reliable turbine is very challenging. Some folks might guess that the big developments would be related to efficiency. I just finished plotting all of the rotor efficiency curves for the turbines currently certified by SWCC and they are in a fairly tight grouping, all peaking in the 30-40% range. The most important developments, in my opinion, have to do with designing a system that efficiently converts wind energy into electricity AND offers reliable power and speed control in high winds. A small wind turbine is an immense engineering challenge. It’s easy to design something that spins in the wind but it is quite a challenge to design a turbine that will survive the extremes and fatigue loading that it will see during its useful life.

IREC: What have you learned about testing and certifying of new turbines since SWCC started its program?

BS: A turbine design with a long track record that is installed at a test site for field testing for the purpose of certification will likely experience some issues during testing but these issues will probably be relatively minor and correctable. The manufacturer may discover a weak component in the electronics or a defect in the manufacturing process. For a new design, certification is a way to prove that it meets the requirements of industry standards in terms of performance, durability, safety and function. What is surprising is how often a new design is just not ready for certification. This proves to me that certification works. The manufacturer designs the turbine, they perform some shakedown testing on a prototype and make some design improvements. But when the turbine is installed at an independent test site in a strong wind regime and is instrumented for data collection, the manufacturer will often discover that the turbine does not perform as anticipated or does not hold up in strong winds. Sometimes it is ‘back to the drawing board’.  When a turbine design makes it through the certification process, that is a respectable achievement.

IREC: Why do you think there aren’t more turbines certified?

BS: As I mentioned previously, many have started the process only to discover that they haven’t actually completed the development of the turbine design. Also, the process of documenting the design calculations and completing the field testing takes a considerable amount of time. The process of testing and reporting can be completed in 9 months, but it typically takes over a year. The length of this process is mainly due to the mandatory Duration Test. After reports are submitted to the SWCC, the certification process involves a lot of back-and-forth between the certification body, the turbine manufacturer and the testing organization, all of which adds another few months to the process. So, we have four turbines that are currently fully certified, four that have been granted a conditional certification and one with a Power Performance certification. Ten others are moving through the process, and new turbines continue to sign up.

IREC: You travel quite a bit internationally for your work.  Is Small Wind a local or global business?

BS: If you are a farmer in the Midwest and you are interested in a wind turbine, you will typically be dealing with a local dealer/installer who will assess your resource and energy requirements, and design and install a wind turbine system that meets your needs. In this case, small wind is a local business.

For the manufacturer of the wind turbine, it is certainly a global business. The standards to which we certify are developed by groups of international small wind experts. There is a new international group of small wind test sites, the Small Wind Association of Testers that meets annually to share lessons learned and technical presentations. There is also a new small wind turbine subcommittee of the IEC Certification Advisory Committee that meets globally to discuss and make decisions regarding the certification of small wind turbines. Part of my work is to collaborate with these groups to maintain global harmonization. For example, a small wind manufacturer sells their turbine to customers in the US, the UK, Canada, Japan and elsewhere. Each country or region has its own certification requirements, but fortunately they are all based on international standards and are therefore harmonized, or similar. The overall goal is to enable the manufacturer to test once and certify anywhere.

IREC: What opportunities or lessons does the U.S. Small Wind industry have to gain from other countries’ experience?

BS: The incentives for small wind in the US are typically state-level, forming a patchwork market with ever-changing requirements. This landscape makes one envious of the national feed in tariff offered in the UK which is tied to their Microgeneration Certification Scheme. We can learn from the folks in the UK that setting a deadline requiring certification is tricky matter; setting it too soon may result in a list with zero turbines. Being unclear about certification requirements doesn’t create the incentive for manufacturers to pursue certification.

IREC: Finally, what advice do you give to people who are interested in or just starting out in the renewable energy field?

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Carving blades at ASU for a Hugh Piggott turbine

BS: I say get out there, go to some workshops, classes and conferences, get educated and trained and network with others in the field. I had a great time at a PV workshop at The Farm in Tennessee with Ed Eaton – one of those great workshops with camping out and homework. I went to the Midwest Renewable Energy Fair when it was in Amherst and met folks like Mick Sagrillo. While I was at ASU, we set up a booth at Windpower in Denver. Grad school at ASU was a really great time, since I had my hands on some real technology and I was teaching workshops alongside folks like Don Harris, Robert Preus and Steve Wilke. These educational events always turned out to be inspiring and bonding. So, don’t stay at home and just read magazines. Get out there with real people and get your hands dirty.


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