How to use tracker control systems to your advantage

In the December 2016 Solar Builder, I discussed the industry evolution from passive to active and dynamic systems. Here’s a primer on control systems and how to make them work for your project.

The Basics

sunlink distributed tracker

Clients frequently ask how trackers will respond to a given condition. Your tracker manufacturer will have a Control Narrative that documents how the system behaves, but strategies include:

  • Excessive Wind. Trackers move to wind stow. Several manufacturers adopt a high-angle stow to mitigate torque. SunLink adopts a low angle stow and activates Dynamic Stabilization.
  • Snow. Trackers move to maximum tilt to shed snow. The higher the tilt, the more snow is shed. For example snow load is reduced by >80% at 60 degrees tilt.
  • Flood. Trackers move to flat to keep modules and wiring out of the water.
  • Obstructions. An abnormal rise in current triggers a fault that stops movement and prevents damage to the tracker.

Along the same lines, clients also ask how the control system works. It varies from system to system but generally there are several layers of communication and intelligence.

The fundamental tracker tilt behavior is governed by the tracker controller at each tracker. Data from individual trackers are sent through the communication network to the plant controller. The plant controller synthesizes data from the trackers and meteorological sensors and makes site-wide decisions about stow and manual control.

From there the data is sent to the local SCADA / DAS system or cloud for use in remote monitoring systems. SunLink’s VERTEX platform helps stakeholders track system performance by displaying critical data in a secure web app.

Impact on Economics

Given the significant role tracker control systems play in the operation of your project, be sure to take the time to discuss monitoring and control systems with your mounting system provider as part of your technology evaluation process.

This diligence is particularly helpful when it comes to commercial and small utility projects. Most developers in this segment opt to monitor performance with simple and relatively inexpensive energy meters. Energy data from the project or a portfolio of projects is accessed through a third-party data monitoring system. While that approach is fine when the system is operating well, it is insufficient for answering questions about why performance varies over time. Are the inverters underperforming? Has it been cloudy? Do trackers need service?

Spread the Wealth: We look at the value decentralized tracker systems bring to a project

A more sophisticated monitoring system could generate more granular data but would cost tens of thousands of dollars. And once implemented, the data is only as good as the insights and actionable information it generates. Too many small developers we talk to are frustrated by a sea of nuisance alarms generated by the data monitoring system and limited O&M resources to do anything about it. After all the effort to put in advanced data monitoring system, the data is ignored. For those reasons, most developers in this segment don’t use sophisticated systems.

Is there a middle ground? Leveraging the intelligence of the tracker system is one way. The same data needed to drive the intelligent control systems of active and dynamic tracker systems can complement energy measurements to answer questions about how the site is performing. Some companies are going a step further. SunLink’s VERTEX platform, for example, is designed to summarize the most important performance metrics and alerts.

Patrick KeelinThe Takeaway

Control systems and their ability to gather data and make it actionable play a pivotal role in ensuring tracker projects perform optimally over the long term. Particularly for the commercial and small utility segment, the ability to leverage real-time project intelligence collected by smarter mounting systems is essential in increasing the value of solar projects without increasing capital cost.

Patrick Keelin is Director of Product Management at SunLink.

— Solar Builder magazine

Coldwell Solar to install 14-MW of Solar FlexRack trackers across 12 locations

Solar FlexRack announced its solar pipeline agreement of 14 MW to install their TDP™ Turnkey Solar Trackers in 12  installations in California for Coldwell Solar.

Solar FlexRack TDP Solar Trackers Installed in Coldwell Solar Agricultural Sites in California

Steve Daniel, EVP of Solar FlexRack said, “Coldwell Solar’s in-depth experience and proven track record has made them the top solar provider serving the agricultural market. Solar FlexRack is pleased to be selected as the supply partner for these solar projects.”

Agricultural operations benefit from distributed solar energy generation that can significantly reduce their electricity costs, stabilize rates and support energy independence. Solar FlexRack’s TDP Turnkey Tracker is an ideal solution for these types of projects. The TDP solar trackers include a full suite of project services and support ensuring projects avoid installation pitfalls. The TDP Tracker bundle ensures systems are constructed for long-term performance and reliability ultimately saving costs on solar project budgets.

“Coldwell Solar performs a thorough inspection of a property to determine the most appropriate, site-specific, solar solution that maximizes cost savings. Solar FlexRack’s TDP Turnkey Solar Trackers were the optimal solution for these agricultural installations ensuring successful projects”, said David Hood, CEO, Coldwell Solar.

Spread the Wealth: We look at the value decentralized tracker systems bring to a project

— Solar Builder magazine

Facebook adding Array Technologies solar trackers to new data center

Array Technologies

Array Technologies, Inc., (ATI) a leader in the solar tracking industry, is partnering with Affordable Solar to install trackers at Facebook’s upcoming data center located in Los Lunas, N.M. Array has been selected to provide trackers for three 10 MW-AC sites to help Facebook’s newest data center be powered 100 percent by renewable energy.

“With decades of innovation and experience under our belt, we’re excited to see large global brands like Facebook adopting renewable energy solutions,” said Ron Corio, CEO of Array Technologies. “Solar technology should be designed and built to withstand the test of time. Array is proud to deliver the only time-proven solar tracker to utility-scale project owners around the world.”

Alongside engineering, procurement and construction (EPC) firm Affordable Solar, Array will install trackers throughout 2017 and complete the first of three 10 MW-AC installations by the beginning of 2018. Affordable Solar was awarded the contract by Public Service Company of New Mexico (PNM) to build the three sites.

Affordable Solar President, Kevin Basselleck, says “We’ll be partnering with Array Technologies, an Albuquerque-based manufacturer of the tracking systems that allow the solar modules to follow the sun throughout the day. They are a global leader in solar trackers and a tremendous local success story. We’re proud to deploy more of their systems right here in New Mexico.”

Mexico solar expansion: Two solar tracker companies with Latin America updates

— Solar Builder magazine

Canada’s IEC working on solar tracker safety standard

IEC PV standards

The International Electrotechnical Commission IEC TC82 WG7 meeting was held recently at the University of Ottawa, Canada. The meeting covered topics on safety, performance and testing requirements of CPV modules, cells and the safety standard for solar trackers and CPV optics. For the first time, a solar tracker safety standard will be incorporated into an IEC standard. Arctech Solar is the only tracker manufacturer who is specially invited by IEC committee to lead the standard drafting.

As a producer and advocate of safety standards for solar trackers, Arctech Solar introduced the tracker safety standards in detail during the meeting, answering all queries from the present and online experts. It has been the only international tracker standard drafted by a Chinese tracker supplier in the history of IEC standardization. The standard has come to the consensus and has been pre-confirmed and improved after serious discussions. It is expected to enter the Committee Draft for Vote (CDV) stage in early 2018.

Mr. Bruce Wang, Chief Technology Officer of Arctech Solar proposed that it is necessary to establish an internationally uniform, reliable safety standard for solar trackers. The proposal of standardization is fully recognized and approved by all experts in the committee. Upon request by the IEC committee, Arctech Solar will submit the final revised standard shortly.

Arctech Solar says it will continuously advocate a more recognized industrial safety standard for solar trackers and promote the tracker industry as a whole.

How are solar trackers holding up in hurricane season? NEXTracker sends an update

— Solar Builder magazine

Solar tracker certified: Arctracker Pro readies for U.S. market with UL certification


Recently, the flagship product of Arctech Solar, Arctracker Pro with the world’s first invented redundancy design, obtained the first UL tracker certificates in China. Arctech Solar is also the first and the only Chinese company approved by UL. Arctracker Pro has met the UL2703 and UL3703 requirements set by UL Company after a series of strict tests and evaluations in China.

The UL Company  is a leading testing and certification institute in the US. All the tests were conducted by UL’s professional testing sites with professional testing equipment under simulated environments to examine the performance of the product under extreme climate conditions. Therefore, the certified product meets up with the international standards of UL2703 and UL3703 in mechanical strength, operational performance and numerous other aspects.

RELATED: We look at the value decentralized tracker systems bring to a project 

Mr. Bruce Wang, Chief Technology Officer of Arctech Solar, indicated that the certificates were a recognition of Arctech Solar’s technical strengths.

“A good product could not have been invented without the efforts of our talented R&D team. The UL certificates confirmed Arctracker Pro’s quality and performance. This will also be a starting point for Arctracker Pro to enter the American market and to be used by American consumers. I believe the smart redundancy design will shortly be accepted by the American market and bring them more cost-efficient and intelligent solutions,” he added.

You can check out this new-to-you tracker in a few months when Arctech Solar attends the 2017 SPI tradeshow in Las Vegas, Sept. 11 – 13.

Arctech Solar has cumulatively installed 10 GW and completed almost 600 projects in more than 10 countries. With a production capacity of 6 GW and 3 GW respectively in fixed mounting structure and tracker fields (a total annual capacity of 9GW), Arctech Solar has grown into a reliable partner in the global PV tracking and racking system field.

— Solar Builder magazine