301 Moved Permanently

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After breaking installation records in 2012, the U.S. commercial PV market entered a moderate slump during the first quarter of this year. Wounded by disappearing state-level incentives and an uncertain outlook for private-market project finance, the market shrank 20% both quarter over quarter and year over year, according to a recent report from the Solar Energy Industries Association (SEIA).

This segment slowdown, coupled with widespread worries about module quality and power losses, places greater pressure on PV system developers and owners to ensure that their current fleets and future projects reliably produce power as promised. After the market bounces back - which SEIA predicts will occur later this year - project performance is expected to remain under intense scrutiny.

Fortunately, new and upgraded system monitoring technologies offer a wealth of performance data designed to reassure investors and other partners by minimizing catastrophic system downtime and identifying subtle performance problems that threaten long-term revenue.

“Monitoring data has finally come to the forefront,” says Matthew Alestra, vice president of operations at Sorapro, a Yardville, N.J.-based provider of solar monitoring products. “With module failures becoming more frequent, the need to recognize faults has increased.”

According to many system monitoring technology providers, the ability to detect system abnormalities and underperformance ties directly to data granularity.

“Granular monitoring is a great way to identify losses that would be undetectable based on a lack of data,” says E. Cosmos Corbin, a system designer at Portland, Ore.-based energy monitoring solutions provider DECK Monitoring. “Over time, all of the losses can add up to a significant cost.”

But for project owners and their operations and maintenance (O&M) partners, how much system performance information is too much?

“For larger systems, it’s not hard to imagine how the volume of data could become positively overwhelming,” says Jay Miller, senior design engineer at groSolar, a White River Junction, Vt.-headquartered provider of design-build, product procurement, O&M and other solar project services. “The challenge for providers will be to demonstrate the value of more-granular data and provide new products that leverage that increased granularity into actionable opportunities to maintain or improve asset performance.”

To make the case for highly granular monitoring, DECK Monitoring recently developed a tool that measures a given system’s hypothetical power losses - and, consequently, revenue losses - that would have persisted undetected with cheaper monitoring options. “Once they have this information, the customer can compare estimated losses to the cost of zone or string monitoring,” Corbin explains.

Miller agrees that the question of data granularity should be examined on a system-by-system and customer-by-customer basis.

“More data is not necessarily better,” he says. “It [is] up to the customer to decide whether there is value added with, for example, knowing the energy production of every single module in an array.”

 

Selective alerts

Alestra reports that system owners and their partners rarely complain about having too much data or too detailed data. Rather, Sorapro seeks to minimize potentially unnecessary and bothersome alerts generated from that information.

“Too many alerts complicate the understanding of the problem and funnel into troubleshooting confusions,” he notes. “We typically default systems to releasing alerts a few times a day, unless otherwise specified by the partner.”

Miller believes performance alerts only truly serve a purpose if they directly lead to a response from an O&M team to resolve or mitigate a problem, or identify an opportunity for better performance. However, other maintenance providers and their partners prefer more comprehensive alerts.

“Given that each customer can have a different approach to the issue, flexibility in the products that monitoring system providers are offering will be important,” he says.

Recognizing that some monitoring customers were experiencing alarm overload, DECK recently redesigned its alarm system to reduce the frequency of what Corbin describes as nuisance alarms. Users can select to receive alerts only on particular issues they identify as important.

Similarly, greater visual customization of monitoring systems’ interfaces allows users with different relationships to the PV installation to view only the system production information that is relevant to their needs. Sorapro, for instance, now offers four different selectable viewing settings - reseller, installer, host and site - on a single interface.

 

Purchase decisions

In the diverse commercial solar sector, projects’ power outputs, system designs, financial packages, ownership structures and other qualities can all vary widely, leading to a range of priorities for system monitoring equipment selection.

For some projects, decisions on granularity, alerts and overall technological sophistication may come down to simple business motivations: Who stands to benefit most if a project performs well, and who stands to lose the most if output suffers?

As Miller points out, more or higher-quality operating data can motivate better decision-making by the asset operator and improved uptime and performance - which, in turn, can lead to more solar energy sold and more revenue.

“For projects financed primarily with debt, there is no expectation that the added revenue resulting from good performance and uptime will be shared with the debt holders,” he adds. “On the other hand, for projects financed primarily with equity, the shareholders will participate in the upside. So, they may support the upfront costs of a more sophisticated monitoring system.”

In some cases, the terms of incentive programs and power purchase agreements set the performance data requirements for a project and, thus, drive monitoring equipment selection. Corbin says DECK Monitoring often works directly with investors and utilities to provide certified data for incentive programs.

Naturally, installations on the larger end of the commercial-scale solar spectrum tend to use more sophisticated, expensive monitoring equipment. Because equipment costs for PV monitoring do not necessarily scale with project size, costs on a per-watt basis for an upgraded monitoring system tend to be lower for larger installations, Miller says. The impact of downtime or subperformance, on the other hand, does scale with the size of the installation, thus further justifying the expenditure.

“In general, the larger the system, the more incentive there is to maximize the system’s production,” Corbin agrees.

PV monitoring product selection also must consider the system owner’s desired level of maintenance over the life of the system. “In some cases, minimal maintenance is expected,” Corbin says. “In these situations, it’s necessary to identify [only] acute problems that dramatically affect system performance and would require a truck roll.

“In other situations, the owner is counting on producing as much power possible from the solar system, and detailed monitoring allows their team to react to a wider variety of issues quickly,” he continues.

Responding to those issues - whether a dusty sub-array or a central inverter failure - requires time and labor expenses. While owners of some large-scale commercial solar farms may keep local technicians on standby to correct faults, doing so would be impractical for smaller installations, Alestra notes. In these cases, alert frequency is often limited.

 

Future of monitoring

For commercial solar projects of all sizes and budgets, many of today’s system monitoring technologies offer increasingly streamlined installation and improved analytical capabilities.

DECK, for instance, recently debuted a new revenue-grade monitoring product with plug-and-play installation using standard socket-meter technology. The device automatically connects to the company’s servers with a cellular modem, eliminating the need for wiring or additional networking steps, Corbin says.

In the field, many modern monitoring systems have become capable of doing more with less, thanks to more sophisticated algorithms. These advancements may prove to be a boon for developers and owners of small-scale commercial PV installations in particular. Sorapro, which supplies projects 2 MW and under, can now often give customers their desired level of data granularity while staying under budget, according to Alestra.

“As algorithms get better for analyzing the data being collected, it may not be necessary to purchase additional hardware to recognize production shortcomings,” he explains. “Obviously, having more hardware deployed at the site to collect more data is ideal, but if the financial model cannot handle the costs of the hardware system, then algorithms can be used to effectively analyze the data and recognize the same faults [as] the additional hardware.”

Owners and operators of larger plants, meanwhile, can - and often must - take advantage of the latest monitoring technologies to meet the stringent, thoroughly modeled expectations of their investors and other partners.

“There’s an increasing emphasis on making comparisons of PV asset performance to expected performance as predicted by customized or tuned models,” Miller says. “Some of the potential benefits are early detection of long-term degradation and a better understanding of how and where to focus maintenance resources.”

From drawing attention to a shading issue to mathematically confirming concerns about subpar module quality, solar monitoring systems often serve as the bearer of bad news to an owner.

However, production data can also be a built-in sales and marketing tool. Sorapro, for example, actively encourages its customers to share their data, visually highlighting cost savings and the installation’s other benefits in the system interface.

“Users are given the tools to see savings and then share with their peer group through social media,” Alestra says. “We streamline the referral process and promote the installation of more solar power.”

As the commercial PV market moves toward recovery and the industry as a whole seeks to assuage widespread fears of inconsistent module quality, real-life, data-backed proof of solar performance could play an even more important role in sustaining business. S

 

Kiley Southwood is a freelance writer based in New York.