Enphase Energy has been creating a market for solar microinverters –distributed inverters that replace a central inverter for solar panels — since its initial product launch in the summer of 2008 and has now shipped more than 500,000 of them.
To keep its lead will not be easy, however. Not only is venture-backed Enphase facing competition from other microinverter developers, but it’s also up against companies making alternative and more mainstream products, like the traditional central inverters. To remain competitive, the Petaluma, Calif., startup will be launching a series of products this year that are smaller, lighter and tailored to different customer types.
In June, it plans to launch its third-generation technology that will boost its microinverter’s average efficiency to 96 percent, a one percentage point improvement from the current version, Enphase’s VP of products, Raghu Belur, told a group of reporters at the company’s headquarters Tuesday. The company will also offer a new installation method that will help shave labor costs. Enphase CEO, Paul Nahi, also hinted at the possibility of offering a warranty that will be longer than the 15 years that it current provides.
In addition, the startup, founded in 2006, is working on a microinverter specifically designed for the larger, commercial installations, Nahi said. Until now, the company has offered the same microinverter for both residential and commercial installations. And, by the end of the year, Enphase is looking at rolling out yet another product that will feature three chips, which will reduce the number of components in its microinverter box and improve its efficiency at power conversion, Nahi said.
The three-chip design will be a departure from the use of a single chip, but Nahi was mum about how the three chips will divide up the core functions of power conversion, communication, control and command. He also declined to talk about the likely efficiency of this new design.
Inverters are electronic devices that accompany every solar energy system. They convert the direct current from the solar panels into alternating current for use onsite (at home or business) or for feeding into the grid. Microinverters are so named because they are much smaller than the centralized inverters that dominate the market today. A centralized inverter is larger and sits near the edge of a solar energy system and converts all the electricity flowing from the solar panels.
A microinverter, which is roughly the size of a half-piece of paper, is attached to each solar panel instead. It’s a design that enables close monitoring of each solar panel’s performance and circumvents the tendency of a solar array to drop its power output collectively even if only a few solar panels aren’t able to perform optimally because of, say, shading or debris that blocks the sunlight from hitting the cells inside the panels.
“Our microinverters are generating more power than you would with a centralized inverter. That’s just physics,” Nahi said.
Enphase executives say they’ve carved out a market for a type of technology that couldn’t take off before Enphase’s arrival, primarily because it was too expensive, inefficient, unreliable and lacked communication functions to effectively monitor performance. The company sells not only the microinverter but also software and services for monitoring the power production of each system. Both installers and system owners can check on the performance of each solar panel by logging into an Enphase portal, and the microinverters will alert them of significant drop in power production.
Microinverters have no shortage of critics, who contend that microinverters haven’t proven their staying power because they are new to the market. They also argue that installing a bunch of microinverters could lead to frequent repairs and replacement. Microinverter advocates have countered that the failure of a centralized inverter will cripple the production of an entire solar array, whereas problems with a few microinverters will only handicap the performance of those few solar panels.
Microinverters do remain more expensive than central inverters. Enphase executives say their gears are 15 percent more expensive, but they have come up with installation methods to cut labor costs. A new installation method, to be offered with the third-generation microinverter in June, will involve Enphase-provided cables with built-in connectors and clips to pin the cables to the racks underneath the solar panels. A single bolt will secure each microinverter, which will then plug into the connector on one side and solar panel on the other.
So, that 15-percent price premium will be offset by a lower installation cost and the extra 5-25 percent electricity production, Nahi said. This sales pitch could work well for installers who care more about the amount of energy to be produced over time than the upfront installation cost.
The majority of its microinverters have gone to residential systems. Enphase is keen to expand its reach in the commercial sector, where each installation is larger and therefore requires more microinverters. The company plans to launch a microinverter with a higher voltage to target the commercial sector, Nahi said. The largest project to date that uses Enphase’s gear has 750KW of generation capacity, Belur said.
The company sells its microinverters and services through distributors and solar panel makers such as Suntech Power, Canadian Solar and Siemens. A major installer who until recently wasn’t an Enphase convert will use the microinverters as a result of snapping up businesses that were Enphase customers. That installer is SolarCity, based in San Mateo, Calif., which bought Clean Currents Solar and groSolar’s residential installation business recently in order to expand its business to the East Coast, said Jake Whiteley, strategic account manager at Enphase.
Although Enphase is the largest microinverter supplier, it’s not the only one and will face a growing competition from fellow microinverter developers. Competitors include SolarBridge Technologies in Texas and Enecsys in the United Kingdom. Its central inverter nemeses include SMA Solar Technology and Power-One.
Transphorm, a Google Venture-backed startup, also is eyeing the solar market with its power conversion technology. Instead of using silicon chips, as Enphase does, Transphorm is using gallium nitride. Enphase also is investigating the use of these more exotic materials, Nahi said, but has no plans to roll out products using them any time soon.
Photo: Enphase’s product testing lab at its headquarters
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