Manufacturer Perspectives on Array Tracking Markets, Equipment and Innovation
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According to GTM Research, “By the end of 2017, 23 percent of ground-mount PV systems globally will use trackers, with that number expected to grow to 44 percent by 2022.” In addition, it reported that solar projects in the US accounted for 70% of worldwide array-tracking system deployments in 2016. In the US and at the utility scale, the ongoing market shift from fixed open-field arrays to tracked ones is well documented and linked to driving project-site characteristics, including location and irradiance values.
Vendors of array tracking solutions for utility-scale projects have a diverse makeup. Some are pure-play vendors that have focused on tracking technology for decades. Others are manufacturers of fixed-tilt racking solutions that have expanded their product lines to include tracking solutions.
For this article, I interviewed team members from five different vendors. Each vendor has a unique history, market perspective and tracking technology in what has become one of the PV industry’s most interesting and exciting areas of growth, both in the US and beyond.
Ron Corio, founder and CEO, Array Technologies, arraytechinc.com
JS: Array Technologies has a long history in the solar industry. Can you run us through its business and product development timeline?
RC: Basically, we started in 1985. We were building concentrator PV modules, and I developed a tracker for the modules. We never commercialized the module, but we did start selling trackers to the remote home market. The real kickoff for the company (then called Wattsun Corporation) was when Home Power magazine bought a tracker—tracker number three. Home Power’s publisher, Richard Perez, wrote a positive review, and that kick started our off-grid home tracker marketing. We probably shipped about 20,000 of those trackers over the years to all kinds of places: the Arctic Circle, Fiji, you name it.
Simultaneously, we always had our eye on utility-scale trackers. We did our first utility-scale project in 2002. It was a 250 kW horizontal single-axis tracker project with BP Solar in Davis, California. It had an individually motorized row system with an offset center of gravity. We also sold some of those trackers in Korea and in Spain. In 2007, we developed our first linked tracker system in Alamosa, Colorado. It was the largest utility-scale solar plant in the US at that time—7.2 MW. That project has almost 11 years on it now. It’s operationally spectacular. There have been maybe three repairs on the tracker system since installation.
At the time, the big news was in Spain, where a lot of companies installed dual-axis trackers because of artificial economics that were driving the market, such as high feed-in tariffs. But the reliability of those things was horrible, which created a lot of resistance to trackers in the US. Everybody believes if it moves, it breaks. What we really had to sell was reliability.
We developed a system that could follow terrain, that wasn’t rigid and that was material efficient. It’s based on the rotating driveline linked-gear design that we came up with for the Alamosa project. It just took off. We called it DuraTrack because durability was the focus, and we had to do a lot of justification for the lifetime of the equipment. The banks were nervous. They saw what happened in Spain, so we had to go through failure mode effects analysis. I had to get scientific about defining the term lifetime, because without good design all kinds of failures can occur.
JS: Array Technologies’ DuraTrack product has been through a few versions at this point. What are some technical highlights of the DuraTrack HZ version 3, and what did your team learn from the various design iterations?
RC: Version 3 came out about 2 years ago, and that was a step forward for us. We had done about 3 GW of projects. We had 250, maybe 300 utility-scale projects under our belt. We had learned a lot and we aggregated enhancements—to installation, to metal use, even to functionality in terms of wind events—into version 3. We’ve differentiated how we deal with the wind. Most tracker manufacturers thin out the metal in the structure and design around a stow-flat or stow-at-a-shallow-angle strategy. The nice thing about our system—and one of the tenets that I instill in the engineering team—is that it’s all about minimization of materials through intense integration of function. Everything has to do as much as it can. When you’re considering square miles of tracked arrays, every small item matters.