Mounting Frameless Thin-Film Modules on Solar Trackers

Mounting thin-film solar panels is a growing trend in the solar industry. Although these panels are typically installed on fixed-tilt racks, they are also becoming increasingly popular in utility-scale solar tracking sites. This is especially true in the Southwest United States, since thin-film modules have a higher temperature coefficient which gives them an energy-yield advantage in warmer climates. Solar tracking technology also has a proven track record of superior performance and higher energy gains in the Southern states, leading to competitive LCOE rates that are too good to pass up.

Credit: ATI

In addition to this natural trend, the recent announcement of U.S.-imposed tariffs on Chinese module manufacturers will lead investors and project developers alike to look for alternative sourcing solutions in order to meet their project deadlines and move pipelines forward. One potential option is the application of thin-film modules manufactured in the United States. Currently, the largest producer of this type of technology is First Solar.

With the solar market rapidly changing, it pays to be ahead of the game.  That’s why Array Technologies Inc. (ATI) made history in 2013 with the shipment and successful installation of thin-film modules on single-axis solar trackers at the 265-MW Mt. Signal Solar project. The largest thin-film solar tracking facility in North America, Mt. Signal Solar boasts more than 3 million First Solar thin-film modules mounted on the state-of-the-art DuraTrack HZ single-axis tracking system from Array Technologies.

With more than 290 MW thin-film modules racked at various sites, Array Technologies’ DuraTrack HZ single-axis solar tracker, and the team behind it, have more experience racking these glass-on-glass frameless First Solar modules than any other tracking system on the planet, including First Solar. As the industry rapidly changes, that expertise will be a safe haven for installers and project owners alike.

Like any industry leader, ATI welcomes a challenge. By design, these glass-on-glass thin-film modules are frameless. What changes when you have to take this into consideration? While the torque tube and gearbox structure of the tracker remain identical, framed modules do not require special supports or custom designed clips for attachment. Frameless thin-film modules require support at specific locations. To install these at the lowest possible price and support them properly, custom racks must be specifically designed to each module make and model.

Credit: ATI

For Mt. Signal Solar, ATI designed a custom tracker structure, including a brand-new patent-pending racking system created specifically for frameless thin-film modules. The system is extremely rigid to prevent module damage while including a well-thought out assembly that allows for rapid deployment on-site, a minimization of materials to keep costs down and assembly tools to reduce install time in the field.

Rapid install times are key, especially at a utility-scale site with over 3 million thin-film modules to install like Mt. Signal Solar. Workers can be trained in less than one day on how to properly install frameless modules on our patent-pending system. While the instructions and tools needed differ from traditional module install, we do have full documentation and a dedicated project management team for assistance in the field.  Our team will train customers on best practices and installation techniques once a project has officially commenced.

Installation times at Mt. Signal Solar were faster than expected, allowing for accelerated solar tracker shipments to the site which were finalized seven weeks prior to the original schedule.

ATI has dedicated time, research and innovative thought to design the new patent-pending rack for mounting frameless thin-film modules on our tracker, as a response to the demands of our customers and key industry trends. As a leading ground-mount solar solutions provider, it is our policy to work with customers to find the most effective configuration of our tracker to bring the lowest LCOE, fastest installation and most reliable product possible to each solar project.

Overall, frameless thin-film modules look to be an important element for solar projects in the United States moving forward. Through constant innovation, a partnership with module suppliers and a commitment to cost-reduction, Array Technologies Inc. strives to create industry-leading solar tracking and racking solutions that directly benefit the needs of our customers and the continued growth of the solar industry as a whole.

— Solar Builder magazine

[source: http://solarbuildermag.com/featured/mounting-frameless-thin-film-modules-solar-trackers/]