Industry professionals point to customization, optimization and software as three key areas where BOS will drive lowered costs in solar PV installation and operation.

Vince Font, Contributor

Short for balance-of-systems, BOS is one of most important yet seldom considered aspects of solar power generation. It’s a catch-all term that encompasses everything beyond the solar panel itself, including inverters, racking systems, cables, wires, and switches. Even software and labor fall under the BOS umbrella.

Currently, BOS accounts for nearly 80 percent of the total cost of solar PV installation — a figure that’s risen rapidly in recent years, up from 58 percent in 2007. The good news is that the cost of BOS components and services is dropping, albeit not quite as quickly as modules themselves, and further innovations are predicted to drive the cost of solar even lower.

Where BOS is concerned, the vast majority of residential and large-scale solar customers are entirely unaware of what it entails and know even less about the role it plays in getting a solar panel to do what it was built to do. Three of the most potentially impactful areas of BOS innovation lie in the areas of customization, optimization and software.

Customization: Made-to-Order Solar

Solar customization describes the discipline of looking at every single aspect of a proposed installation prior to spending a dime on equipment. According to Zuzana Piras, marketing communications manager for SolarBOS, the extent to which balance-of-systems components is forgotten is pervasive, even among commercial and large-scale utility solar systems installers hired to perform the work.

Circuit breaker recombiners and floating disconnect combiners make up the BOS. Credit: SolarBOS.

“There are many, many pieces to the puzzle and often the most expensive and most critical components with the longest lead times are thought of first,” Piras said. “The electrical balance of systems components tend to be at the end of this list.”

As a result of this common oversight, solar installation costs can rise and lead to extended time frames for a project’s completion. “This is where our customers could save themselves a lot of time, money and headaches,” Piras said, adding that clarifying technical specifications and seeking customized solutions in advance is critical to the timely completion of any solar project.

“No two solar projects are the same,” Piras said. “If we figure out at the beginning of the process what someone needs, it saves everyone a ton of time and problems.” Piras said that customization can also provide a more accurate accounting of a solar project’s approximate cost long in advance, allowing for solar adopters to secure necessary financing.

Optimization: Juicing the Array for All Its Worth

The concept of optimization isn’t new, and it’s certainly not new to solar. But a growing number of PV product manufacturers are leading the charge in design improvements that can do more with less, reducing the overall cost of solar installation.

Trina Solar, a module developer headquartered in China, is developing “smart” solar modules that provide maximum power optimization by enabling diagnostics and monitoring of individual modules in real time. Smart solar modules, designed for plug-and-play functionality, also greatly reduce installation times and can result in a simplification of the supply chain, which translates to decreased systems cost.

In addition to developing smart solar modules, Trina is one of the first developers to introduce utility-scale modules capable of operating at 1500 volts, compared to the standard of 1000 volts. The significance of increased voltage capacity in solar systems is that it lowers the loss of power during transmission. Systems configured to operate on higher voltage can also accommodate longer strings of modules, which in turn decreases the amount of necessary components within a given solar installation.

According to Jeff Dorety, president of the Trina Solar Americas Region, optimization and improvement of solar equipment will play a significant role in the proliferation of commercial and residential solar by “chipping away at the increased costs associated with the reduction of the ITC [Investment Tax Credit].”

Zuzana Piras, marketing communications manager for SolarBOS. Credit: RenewableEnergyWorld.com.

Jing Tian, head of global marketing for Trina Solar stands in front of the Trinasmart Module display. Credit: RenewableEnergyWorld.com.

Other areas of BOS optimization focus range from the electrical to the mechanical. “We are also working with suppliers to add features that can reduce the number of mechanical mounting parts needed,” said Jing Tian, Head of Global Marketing for Trina. “This can greatly reduce the overall system BOS cost.”

Another company making headway into the reduction of BOS cost through optimization is Alion Energy, an EPC and O&M service provider that employs robotic technology to perform tasks typically handled by humans, like panel installation and maintenance. This reduces time frames and associated labor costs, and can also improve panel performance, particularly in environments where corrosive elements can reduce the efficacy of solar modules.

Software: Programmable Energy Management Driven by Energy Storage

Software is the technology that drives the world, and nowhere is that most evident than in the solar industry, where an interesting transformation is taking place: inverter manufacturers are beginning to take on the attributes of software developers. It’s a curious hybridization within an industry traditionally planted firmly in the physical world.

Brian Korgaonkar, senior product manager for Enphase Energy, described it as a “change of mentality” and a “moving beyond the solar solution to understand how everything works together.”

The software programs that power the activities of solar arrays are among the most rapidly developing and commonly deployed facets that comprise the full solar BOS picture. Solar software is used to perform a variety of operation-critical tasks, including tracking energy production, monitoring whole-system health, gauging panel performance, and programming battery storage and deployment options.

Mark Fritts (left) and Brian Korgaonkar (right) stand in front of the Enphase AC Battery. The increasing interest in battery storage is driving some inverter manufactures to focus on software to control Energy Management Systems. Credit: RenewableEnergyWorld.com.

It is an area of the solar industry rife with opportunity for development, which is what’s driving companies like Enphase Energy to transformative growth.

“We now have an equivalent number of software engineers and hardware engineers,” said Mark Fritts, Enphase’s director of product marketing. “Historically, you would have seen a much different balance. The interconnected nature of our solution requires a lot more sophistication on the software side, that glue that stitches everything together.”

BOS Cost Drops May Keep PV Affordable

Across the world, solar power incentives are on the wane. In the U.S, the ITC is facing imminent expiration and when that happens, residential and commercial PV may slow to a crawl due to increased costs of installation and operation — a prospect that could deal a major setback to an industry still in its formative years.

But in deus ex machina fashion, innovations in BOS could offset that increased cost. Some experts project that prices for solar systems will drop by 40 percent between now and 2020, fueled by technological improvements in customization, optimization and software. If nothing else, BOS innovations will serve to keep the solar industry alive and kicking long after the inevitable sunset of government subsidies. ◑