Solar Power World has been intrigued for quite a while about the differences between central inverters and microinverters. In particular, we were curious about what those companies see happening in the inverter segment of the market. Fortunately, we already had a friend of the magazine on tap who could answer those kinds of questions for us — Craig Lawrence, VP of Marketing and Product Management for SolarBridge Technologies. Here are his thoughts on the subject:
SPW: What is the biggest change in the inverter industry in the past 12 months?
CL: Other than the obvious declines in prices across most segments of the inverter market, one big change that we are witnessing (and participating in) at SolarBridge is the significant trend towards the increased use of distributed electronics in commercial PV systems. We are seeing a lot more string inverters being used in large commercial sites that would previously have used larger central inverters. And 12 months ago, it was not common to see microinverters used in large commercial PV systems (greater than, say, 50 kW). Now, we are routinely seeing at SolarBridge and amongst our microinverter competitors, AC modules and microinverters used in commercial systems up to 1 MW. Commercial-system owners are recognizing the benefits of distributed electronics in terms of energy harvest, system up-time, safety, and operations-and-maintenance costs. This is the same kind of trend that has been happening in IT, where the benefits of distributed processing and redundant systems has made it the dominant paradigm in computing. Interestingly, this trend has not yet reached the large utility-scale PV systems, although we expect that over time, it will. Twelve months from now, I would expect to see some of our first AC module installations in utility-scale PV plants.
SPW: What are the biggest obstacles you see that the inverter market has to overcome?
CL: Quality and reliability remain the single biggest problem for the inverter market. The market has a track record of releasing products that do not meet customer expectations in terms of failure rates, up-time and quality. A recent study published by SunEdison pointed to inverters as the single largest source of maintenance in their PV fleet —more than 50%. While module lifetime has been established at more than 25 years, inverter lifetime is still in the 5 to 10-year range. And in a central inverter system, a failure means lost revenue and expensive emergency repairs. SolarBridge has been almost singularly focused on product reliability since its inception, and we were the first company to offer a 25-year inverter warranty, backed by a patented design that eliminates all of the components that typically fail prematurely in inverters. Our goal is to set the expectation for the industry that an inverter can and should be as reliable as a module, and that an AC module with an integrated warranty from the manufacturer is something customers can rely on for the life of their PV system.
SPW: What are the most common solar applications for microinverters?
CL: To date, grid-tied residential PV has been the most common application for microinverters and AC modules. The most recent data I’ve seen is that microinverters now account for over 30% of all residential PV in the United States, which has been an amazing disruption to the PV market. In the last 12 months, however, we have seen an increased interest from our customers in the use of AC modules in commercial PV systems up to, and sometimes greater than, 1 MW. Our belief is that the main driver is the reduction in O&M costs as a result of having a single point of failure in the system. This allows maintenance to be scheduled on a predictable basis.
SPW: Why is SolarBridge Technologies doing a technician-training roadshow?
CL: SolarBridge is a component supplier — we exclusively provide microinverter and monitoring solutions to module manufacturers who integrate these technologies into their AC module products. So we are at least one step removed from the installers and technicians who purchase and install these solutions. As we now have over 10 AC module partners offering products with our technology, and a new second-generation microinverter launched, we felt the time was right for us to help promote our partners’ solutions to the installer and technician market.
We believe that our products can help accelerate installers’ businesses by providing a solution that harvests more energy, is faster to design and install and reduces their operations-and-maintenance expenses. Unlike other manufacturer roadshows, ours has been a collaborative effort with our AC module partners. We have brought our partners with us on the roadshow, visiting their customers and getting first-hand feedback on our products. We have been to 15 cities and trained more than 500 installers in every major U.S. PV market. It has been an invaluable experience, and we plan to repeat this annually — and globally — as we expand to new countries.