On Thinking About Solar Trackers and O&M

By on March 21, 2017

In my new role here at NEXTracker as VP of Asset Management, I’ve been learning a lot about how we do operations and maintenance – more specifically, how our customers handle their O&M practice with regard to our tracker.  No doubt, single-axis trackers (SATs) have become increasingly popular because of the higher energy yield they produce compared to fixed-tilt systems. But I can’t help but wonder why so many contractors and developers are still gun-shy about buying SATs for their projects. A possible conclusion is because of the presumed costs of maintaining such systems.

I decided to team up with my long time colleague, Rue Phillips, CEO of 365 Pronto, to author a white paper, “Tracking Your Solar Investment: Best Practices for Solar Tracker O&M.”  In this paper, we dive deep and analyze the factors to consider when evaluating tracker technologies from an operations and maintenance perspective.  We discuss how the O&M costs—and in particular NEXTracker’s O&M costs—reduce the project’s levelized cost of energy (LCOE).

This blog series is based on that white paper. In the first post of the series, Rue and I review the importance of smart O&M planning, budgeting and proactive strategies, as well as other cost issues such as O&M considerations in racking type selection and the O&M cost per kilowatt-hour advantages of self-powered SATs.

Successful O&M Planning

For any installation, planning and budgeting for system O&M are key steps in project development. These steps are critical for distributed generation applications as well as utility-scale systems, and both require thoughtful analysis of costs along multiple dimensions: conditional versus routine; preventive versus corrective; and site versus component. While time pressures can cause some developers to delay development of a thorough O&M strategy to later in the project’s lifecycle, successful upfront planning can help inform decisions on system design. The purpose of a proactive O&M strategy is to maximize system energy output while minimizing operational costs, thereby improving the project’s financial return.

I wholeheartedly believe that finding the right partner to help develop a comprehensive O&M strategy at the design stage  is an important part of selecting your system component.  With accountability, true partnerships and the right components, project owners will have a plan for the project’s entire service life that covers aspects such as site management, predictive maintenance execution, system monitoring, and long-term asset management.

O&M Considerations in Racking Type Selections

When planning for O&M, it’s important to understand how costs scale with and are influenced by project attributes such as installed power capacity, land area, and racking type. Certain costs that represent a large portion of the total O&M budget, such as inverter maintenance, scale with the capacity of the plant but are independent of racking type. On the other hand, vegetation management and PV module cleaning costs are driven both by land area as well as the specific racking technology.

In the chart below, for example, O&M costs for array cleaning and vegetation management are shown to be considerably higher for typical linked-row tracker systems than for decentralized systems.          

O&M costs NEXTracker v.s. Linked Row System

Looking at tracking systems specifically, it should be emphasized that O&M represents a small percentage of a system’s overall O&M budget—approximately 3% in the case of decentralized trackers—which is significantly less than inverter and other balance of system O&M costs. 

When evaluating fixed-tilt structures versus trackers, O&M costs should be considered on a per-kilowatt-hour (kWh) basis since energy output varies significantly between these system types. For example, although the tracking system adds 3% more O&M cost on a capacity basis, it will produce 20% more energy. The O&M cost for the tracker then becomes 17% less on a per-energy-unit basis.

In my next blog, I’ll explore tracker system design and technology considerations, with a strong focus on the O&M advantages of decentralized versus centralized single-axis trackers. The post will also explore panel cleaning and vegetation management, redundancy and resiliency, drive system and power requirements, fasteners, and torque versus tension. Read the 2nd post on this series here

(If you’re interested in reading the entire “Tracking Your Solar O&M Investment: Best Practices for Solar Tracker O&M” white paper, you can download it HERE. And in case you missed all of us who participated  (or want to hear us again) on the recent Greentech Media webinar, “Solar Field of Dreams: Tracking Your Solar O&M Investment,” listen and download the presentation HERE.)