Commercial PV System Data Monitoring, Part One: Page 2 of 11

Data monitoring systems that are well designed, installed and maintained can ensure that a PV asset achieves the highest return on investment by minimizing operations and maintenance (O&M) costs and system downtime. Not only is the risk of underperformance or nonperformance unacceptable to owners and investors, but federal laws also define and specify data monitoring requirements for utility-scale PV systems that fall under the jurisdiction of the Federal Energy Regulatory Commission and the North American Electric Reliability Corporation.

“No traditional power plant would be built without extensive monitoring for determining that it is operating properly at all times and figuring out what is wrong when it is not,” notes Chuck Wright, principal at PowerDash, a monitoring services provider. “Likewise, renewable energy will not be a serious component of the world energy supply unless monitoring is an integral component. It is just a cost of doing business properly.”

Nevertheless, Power-One’s Tansy observes, “At the residential scale, data monitoring is often considered optional because performance-based incentives are generally not involved.” While it is certainly possible to build a business case for offering data monitoring as a standard feature on residential PV systems (see Summarizing the added value gained from data monitoring, Blair Kendall, director of business development at Southern Energy Management, a North Carolina–based PV integrator, says: “High-quality, accurate and accessible solar PV monitoring for commercial systems serves two primary objectives. The first is to provide certainty to CFOs and investors that they are getting what they pay for. The second is to facilitate effective O&M on the system to ensure maximum system uptime and production. Both of these goals are really about mitigating investment risk that further facilitates greater investment in commercial PV systems.”

Value to owners and financial backers. According to Adrian De Luca, VP of sales and marketing at Locus Energy, a provider of software solutions to the distributed renewable energy market, the value of data monitoring for system owners and investors is twofold. “First, monitoring systems enable accurate and timely customer billing,” he notes. “Second, they maximize system uptime and therefore the return on investment.”

For owners and backers of commercial-scale PV systems in particular, the ability to manage a portfolio of distributed PV plants in a unified manner may be as important as the ability to track individual plant performance. Many monitoring solutions providers offer multiplant, portfolio-level management. The caveat, of course, is that data for every site must be centralized with a single vendor.

Because they can optimize system performance and return on investment, data monitoring solutions also reduce financial risk. Financing large PV systems is often contingent upon having a performance guarantee contract in place as a risk mitigation mechanism for investors. (See “PV Performance Guarantees” June/July, 2011 [Part One] and August/September, 2011 [Part Two], SolarPro magazine.) Data monitoring is central to every performance guarantee—it gives the guarantee its teeth and makes it enforceable.

Without accurate data monitoring, actual system performance in the field cannot reliably be compared to what was guaranteed. Therefore, performance guarantee terms need to outline minimum data monitoring requirements commensurate with the performance risk. Uncertainty in data collection may make it difficult, if not impossible, to collect damage payments.

While performance guarantees may not be in place for the majority of small- to medium-sized commercial PV systems, the basic premise holds. Effective data monitoring not only helps to identify system performance problems, but it also helps to resolve them.

“Constantly measuring power production against expected performance benchmarks allows the owner to determine if and when remedial action is necessary,” explains Mark Lane, director of product management at ArgusON, a provider of site monitoring and services. “Assisting system integrators or O&M providers to resolve problems and get solar power systems back online as quickly as possible is part of the value that data monitoring adds for owners and financiers,” he concludes.

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