By Gil Miller
As the world market for solar continues to grow, some warn that solar modules run the risk of being viewed as commodities, as polysilicon already is. Module manufacturers try to avoid being labeled as commodities by having their own levels of vertical integration and different versions of technology. But, realistically, the average consumer often never notices these nuances. Without distinct and meaningful product differentiation that consumers can readily identify, the ultimate deciding factor becomes price.
There lies the commodity trap, ready to catch any manufacturers who neglect to repeatedly evaluate and promote their own products and whose competitors advance their own products to offer a more appealing product for the price. In this sea of variables, many solar module manufacturers and installers find themselves struggling to stay ahead of the competition and out of the commodity trap.
To avoid this trap and gain market share, manufacturers and installers must truly differentiate themselves by providing meaningful and distinct technologies that reliably offer dramatic benefits to end users. These benefits include increased energy harvest, the ability to monitor a solar array’s output remotely, reduced Balance of System costs and increased safety features that protect the investment. One newly developed technology does all this: the smart junction box.
Adding ‘Smarts’ to the Junction Box
The Smart Junction Box (SJB) advances the basic solar junction box beyond a humble case for diodes and connections between the solar module and the rest of the system. This new junction box is ‘smart’ thanks to sophisticated power electronics embedded in it that provide system monitoring and increased total energy harvest. As an example, the SJB AP300 developed by Azuray Technologies can recoup up to 99.2% of power lost from modules experiencing shading, module mismatch or soiling. This translates to an increase up to 30% in total energy harvest for the array.
The Azuray® AP300 achieves this by moving the function of Maximum Power Point Tracking (MPPT), commonly found only at the inverter level, to each solar module. This gives the system greater control over its energy output and increased ability to adapt to shading and soiling conditions. Though this effect can also be achieved through separate MPPT DC-DC converters, the SJB reduces Balance of System redundancies created by using a separate junction box and power optimizer.
Embedding power optimization electronics in the junction box gives solar modules ‘smarts’ they would not otherwise have. As a result, they are able to harvest more energy in the same array space than otherwise possible?a key consideration when space is at a premium or when partial shading cannot be avoided. These benefits open up opportunities for solar suppliers to command premium pricing in an increasingly crowded solar market thanks to distinct and meaningful product differentiation.
Greater Energy Harvest
Naturally, energy harvest is at the forefront of most system owners’ minds. When you consider shading on less than 10% of the surface area of a PV system can lead to a 50% decline in energy production, it’s unfortunate that traditional modules cannot improve their own energy harvest by making independent, automatic adjustments to common challenges like shading, soiling or module mismatch.
Fortunately, power optimization provided by SJBs gives solar modules the ability to increase performance efficiency and, therefore, energy harvest. System owners enjoy a faster return on investment because power otherwise lost to shading, mismatch or other obstructions is recovered and used.
For example, a 10-module array with morning shade covering the lower five percent of three modules might produce 1600W. By utilizing power optimization electronics on the shaded modules, array production increases to approximately 2050W?more than a 28% increase in power production.
Reduced BOS Costs
Another concern of most system owners is their initial investment. In total, Balance Of System (BOS) activities such as labor, racking, mounting, cabling and power electronics equipment account for slightly more than 50% of the total cost of a PV system. With its combined functionality, the smart junction box developed by Azuray Technologies reduces redundant Balance of System costs compared to mounting a separate junction box and a distributed power electronics device, such as an MPPT power optimizer on the back of a module. By recouping power otherwise lost to shading, module mismatch or soiling, SJBs like the AP300 can yield higher energy harvest using fewer modules and connections.
Smart junction boxes can also reduce design costs. Because SJBs offer solar installers greater flexibility to design systems that avoid or adapt to partial shading, installers can offer simpler design schemes and shorter design periods that result in reduced costs to the owner. These savings in the planning process can lead to lower Levelized Cost Of Energy (LCOE) and an even greater reduction in BOS costs like wiring, housing and labor costs.
Monitoring and Communication Capabilities
The communications capability of the smart junction box provides the foundation for a truly systemic approach to PV installations. By creating communications links between all components of a PV array, the SJB allows the system to achieve even greater efficiency and energy harvest. The Azuray® Communications Gateway (ACM300) is a critical part of this new systemic approach as it collects data from solar modules and calculates the most efficient operating point for the array. In addition, it controls the power optimizers to reach and maintain that efficiency point over the course of the entire day.
The information communicated by the distributed power optimization electronics to the communications device can be viewed via the web or exported to email or FTP, providing the installer and owner with both PV energy production data and information on the health of the various SJBs within the system. Besides daily monitoring, integrated communications devices can be used as remote diagnostic tools and warranty repair indicators to maximize system uptime and energy harvest even further.
Safety Shutoff Features
Safety is another real-world concern for system owners. Particularly in rooftop installations, the presence of high DC voltages is a significant safety concern, especially in case of fire. In these emergency situations, solar modules can continue to generate high-voltage energy even after the AC and DC disconnects are engaged. This potentially exposes emergency responders to high voltages that impede their efforts to put out fires and/or rescue trapped inhabitants.
Using power line communications, the ACM300 offers remote shutoff of the power coming out of the AP300 smart junction box. The robust power line link between the ACM300 and the AP300 runs over the existing DC wires, avoiding any additional wiring expense.
As the solar industry continues to mature, experts foresee profit margins shrinking in an effort to reach grid parity goals. To avoid losing profitability, solar manufacturers and installers must find opportunities to dramatically differentiate their products and services to command premium pricing.
Smart junction boxes like the AP300 offer this opportunity today. As a complete package of embedded MPPT power electronics, SJBs increase total energy harvest and provide monitoring and safety features modules alone do not possess.
The smart junction box is the future of solar. Those who adopt these advancements in technology today will find themselves at a significant advantage over their competitors in the ever-more cramped solar industry. Those who sit back and wait are likely to find themselves stuck deep in the commodity trap.
Gil Miller, Vice President of Business Development at Azuray Technologies (www.azuraytech.com), has more than 23 years’ experience leading emerging electronics companies. From 2004 until joining Azuray Technologies, he was the co-president and founder of Siren, Inc., a consumer electronics company specializing in digital audio and digital photo frames. Miller headed business development and product marketing for the Rio Group, a digital audio pioneer, between 1999 and 2004. Earlier he ran worldwide LCD projector product lines for InFocus from 1995 to 1999 and held senior positions at Apple Computer, California Devices, Inc., and Advanced Micro Devices. Miller attended the University of Texas, where he earned his MBA, as well as Temple University and Drexel University.
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