The Silicon Valley mantra of smaller, faster, cheaper hasn’t really applied to the Photovoltaic (PV) market—until recently, that is, when micro-inverters and optimizers started being employed in solar installations, according to the solar market research firm iSuppli Corp.
Rather than reducing costs the way microchips do—by becoming smaller and faster—PV systems historically have achieved the “cheaper” part of the equation by delivering on the three efficiencies of solar technology: efficient energy conversion, efficient manufacturing methods and efficient use of materials.
However, the PV market is beginning to take a page from Moore’s Law with the arrival of Module Level Power Management (MLPM) systems, a product area consisting of micro inverters and optimizers.
MLPM systems are beginning to gain favor because of the increased energy harvest that they enable at the individual module level instead of the total module string level. Depending upon the location of installation, such as “shadowing” conditions, MLPM solutions can harvest 3 percent to 20 percent more kilowatt hours of PV electricity during the course of a year. And while they cost significantly more per watt than traditional inverters, that gap is rapidly narrowing.
As a result, total MLPM shipments are forecasted to reach 7.8 Gigawatts (GW) by 2014, managing a Compound Annual Growth Rate (CAGR) of a whopping 204.3 percent, up from just 30 megawatts in 2009.
Micro-inverters perform the same general functions as traditional inverters except that they work on a per-module basis rather than for a string of modules. Optimizers perform the Maximum Power Point Tracking (MPPT) algorithm and are often used in conjunction with a string inverter that has been cost-reduced by removing the MPPT function.
Applying Moore’s Law
How does Moore’s law play a factor in these systems? The Bill of Materials (BOM) for MLPM systems are more chip intensive than that of regular inverters. Micro-inverters also are adopting some of the latest advanced semiconductor technologies, such as Gallium Nitride (GaN) power components.
Being chip intensive is actually helping these systems by allowing them to drive out costs, as they benefit from functional integration and the lower power draw from the constantly evolving chip-process technologies. The use of chips is also allowing MLPM system providers to offer much longer lifetime warranties than traditional inverters, to 15 years and beyond—which more closely aligns with the payback lifetime of PV installations.
The U.S. residential installation market, in particular, has fallen in love with micro-inverters as they make it easier to design a PV system for a specific roof. Optimizers have found an interesting interim market in which they are being used to boost the harvest of already installed modules that have dropped below installation warranty levels. Optimizers are also used to create so called Smart Panels—a possible margin-enhancing path for module suppliers.
iSuppli believes that traditional string and central inverters will continue to be preferred in many regions and applications, especially utility-scale projects, but that MLPM solutions are set to seriously penetrate the rest of the installation market.