Solar Builder

JUL-AUG 2016

Solar Builder focuses on the installation/construction of solar PV systems. We cover the latest PV technology (modules, mounting, inverters, storage, BOS) and equip installers/contractors with tips and tools to make informed purchasing decisions.

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40 J U LY / AU G U S T 2 0 1 6 CUT THROUGH THE HYPE Five tips for purchasing from a mounting manufacturer By Patrick Keelin, Director of Product Management, SunLink PV POINTERS 1 ) E N G A G E M A N U FA C T U R E R S E A R LY Successful renewable energy projects optimize the power generation equipment in accordance with a site's unique conditions. Unsuccessful projects fight their envi- ronment. Rather than advocating a one-size-fits-all solution, your mounting system manufacturer should be involved in project planning from day one to recommend options as to how to best work with site realities like heavy snow, uneven terrain, poor geotechnical conditions and more. In addition, when it comes to portfolio scale projects, ask what products are in the development pipeline. Rapid innovation in solar means that what's available today may not be the best solution for a project installing 18 months from now. 2) FURTHER INVESTIGATE MODELED ASSUMPTIONS Seek out partners who are able to advise you as to 1) how different assumptions affect modeled results, and 2) how likely you are to achieve your modeled results based on historic performance. Your mounting solution provider should have the expertise to optimize project design to help your realize the highest possible energy yield. For example, pushing the assumption that extending tilt range improves prod- uct actually has diminishing returns. Instead, looking closer at your ground coverage ratio can do more to improve yield. Your project partner should also be able to help you reduce the delta between modeled and actual performance. 3) REVIEW THE RELIABILITY DOCUMENTATION In the world of solar product development, relentless price pressure can either drive rapid innovation or leads to solutions that cut corners. Evaluate which is the case for every product you consider. If the manufacturer has a bankability report, have your engineers read it and engage with the manufactur- er to ask questions, dive deeper and learn more. Don't just check the box. A bankability report is nonbinding, and it's not an endorsement. It is an independent assessment of the product. The final decision is with the buyer. Beware of misleading metrics. For example, Mean Time Between Failures (MTBF) is used to characterize how long components in a system will operate before failing, but applying MTBF to solar trackers can be a misleading. Intuition says that half of the components in question will fail before the mean, and half will fail after the mean. In reality, with a constant failure rate, two- thirds will fail before the MTBF. The issue is that MTBF is a single number and says little about the dis- tribution of failures over time. Reliability is a clearer, more actionable statistic. Reliability asks how many components will still be working after a given number of years. Continuing the example above, a 40-year MTBF is equivalent to a 40-year reliability of one-third. 4) CHOOSE YOUR MAINTENANCE STRATEGY When you choose a mounting solution, you are at the same time choosing an anticipated maintenance path and budget. The only no-maintenance mounting alter- native is a fixed tilt system. Centralized trackers that uti- lize 1-2 drives per MW and commercial off-the-shelf components require greater investment on the front end, but need minimal attention over the long term in the context of the entire solar plant. At the other end of the spectrum, distributed tracker systems introduce thou- sands of control and actuator assemblies into harsh envi- ronments, requiring a carefully designed component replacement strategy to ensure long-term performance. In either case, make sure that a realistic maintenance plan is discussed before the final purchase decision. 5) LOOK FOR SCADA AND DATA MONITORING SUPPORT SCADA is often last to be considered in the design of a project, but it is an enduring touch-point that accounts for a disproportionate share of issues post commission- ing. A solar portfolio manager recently told us that 80 percent of his project alarms are due to communications failures. The tech industry gives us a roadmap for dra- matic improvements in how projects are monitored and controlled. When it comes to mounting solutions, you want a partner, not a vendor. Those partners who are truly invested in seeing your projects succeed and helping your business grow will not only be open to having a trans- parent discussion about optimizing your solutions, they will be enthusiastic about it. Don't be shy about asking the tough questions. As Director of Project Management, Patrick helps define SunLink's next generation of products and servic- es benefiting the solar PV industry.

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