Overlooked Solar Balance-of-Plant Technology Getting Its Due
While firms like Nanosolar and Solyndra garner the lions share of media and VC attention, one facet of the solar ecosystem has been relatively overlooked -- inverters and balance of plant. While innovation marches on in PV materials, inverter technology and solar installation architecture has been relatively stagnant. Until now.
Innovative firms like SolarEdge are challenging the way PV systems are installed and wired together as well as influencing the way modules are manufactured. And they’re doing it with ICs and semiconductors, not with PV materials.
SolarEdge, in its first interview with the press, has revealed a few tidbits about their technology and announced to Greentech Media that the company is engaged in sales agreements, testing agreements, joint development agreements and has booked significant initial orders for its products from major module manufacturers and system integrators.
And remarkably, despite less than splendid market conditions, SolarEdge has a number of term sheets and will be closing on a $20 to $25 million VC round B in the coming days or weeks. Its previous round was $11.8 million in funding from Walden International, Opus Capital and Genesis Partners.
I spoke with Lior Handelsman, VP and Co-founder of Israel-headquartered Solar Edge on Monday, Dec. 1.
The typical solar installation strings together a number of, say, 180W solar panels. Because they are in series the panels act like batteries and the poorest performing panel or a partially shaded or dirty panel can degrade the performance of the entire string. According to SolarEdge, partial shading of solar panels can result in a dramatic reduction of solar panel output. One completely shaded cell can reduce a solar panel’s output by 40 percent to 95 percent.
There are a few different approaches to solving this problem. Startup SolarEdge and a few other firms are leading the way.
The DC approach used by SolarEdge (as well as National Semiconductor, Tigo Energy and a few others) optimizes the Maximum Power Point current for each module and monitors each panel via an ASIC embedded in the panel. SolarEdge claims that the performance of a PV solar system can be improved by 15 percent to 20 percent by using the company's chips and inverters. There is also a reduction in cabling costs and wiring losses as well as an added element of security and panel-level monitoring.
An alternative AC approach integrates a micro-inverter with each panel and performs the DC/AC conversion at the panel itself, not at the inverter. Rockport-funded Enphase as well as GreenRay and Petra Solar are using variations of this method.
There are some advantages and disadvantages to each architecture. In my conversations with the notably conservative installer industry, many were enthusiastic about new energy harvesting technology but reluctant to work with a product that was not yet field proven like the micro-inverters/AC approach.
Nevertheless, expect new thinking and innovation in solar installation architectures because of innovative ICs from the likes of SolarEdge.