‘Floating’ Solar Tracker Technology Boosts Efficiency and Profit for Solar Farms

Trabant Solar’s innovative floating tracker increases profits for solar farms by more than 20% and efficiency by up to 42% over fixed-position systems. Pre-programmed controller, which scales up to 25 trackers, relies on easy-to-use function blocks from a special Siemens solar library. 

Solar energy is becoming more viable as the green movement grows and pricing gets closer to matching existing utility rates. Infrastructure improvements such as the trackers that help position solar arrays are helping make solar even more competitive.

Ron Sade came up with a technology that can increase the profits of solar farms by more than 20% over fixed position systems during their two-decade lifetimes. His technology makes it possible to locate solar array farms in wetlands, sand, rock and other unstable or unusable conditions that weren’t suitable using conventional infrastructures.

Sade eliminated the masts and poles that secure a solar array to concrete foundations. Instead, his tracker uses a ballast pan filled with dirt, gravel or sand. The pan, which holds 9,000 pounds, floats on the surface of the ground, anchors the array even in winds higher than 90 MPH.

Sade decided to bring his solar tracker to market, so he founded Trabant Solar Inc., based in Richmond, Va., in early 2010. After more than 11 years in the solar industry as a project developer in the U.S. and abroad, he says the time was right to “stop digging for gold and start selling shovels.”

In addition to coming up with an improved mounting technique that works in many environments, Sade also wanted to improve the reliability and performance of previous tracker control boxes. To do that, he needed a technology partner with off-the-shelf products and the sophistication to reliably control large arrays at a single farm. The partner also had to provide global service.

Trabant TT and HT Solar Trackers 

Today, Trabant is shipping two products:  tilted (TT) and horizontal (HT) Ballasted Solar Trackers. Trabant’s Solar Trackers are already controlling 12 Monocrystalline solar panels producing 10 kWp of electricity at a private installation outside of Toronto, Canada. Many more installations are underway or planned – including a 33 MW, 5,600-unit project in Leon, Mexico.

“More than ever, we must reinvent ourselves and move ahead with renewable energy,” Sade says. “A big part of that is in the photovoltaic (PV) market. The U.S. is in the early stage of PV development and there is still time to enter with good products on an international scale.”

Trabant’s TT-72 and HT-72 Solar Trackers accommodate 12 or 18 of the standard 72 cells solar modules from any manufacturer. The TT-60 and HT-60 Solar Trackers accommodate 16 or 24 of the standard 72 cells solar modules from any manufacturer.

Control Confidence

The ballast pan used on both Solar Trackers that floats on high- or low-density ground is a game changer, but it’s not the only innovation. Trabant’s automation and controls technology partner, Siemens, provided the tested technology that adds instant credibility to the Trabant Trackers, Sade says.

“Siemens is a technology oriented company, and the quality of Siemens personnel is outstanding,” Sade says.  “Siemens has a network of technicians and engineers who fully understand the entire market. The name Siemens alone is absolutely a value add.”

The Trabant Solar Trackers are controlled by Siemens Simatic S7-1200 Siplus controller with onboard Ethernet communication. The extended temperature controller is a standard controller enhanced to handle harsh environmental conditions.  Housed in a combiner box, it includes outdoor rated devices including a 24vdc power supply for linear actuator power, a RS485 Serial interface for Modbus Serial line actuator communication, RS232 Serial communications for GPS clock and wind sensor and DC string combiner and fuses. An optional touch screen operator panel is also available.

Preprogrammed and Preinstalled

The controller is preprogrammed with Simatic Step 7 Basic software with easy to use function blocks that are part of a Solar Library developed by Siemens.  The solar positioning algorithms at the heart of these function blocks were developed by the U.S. Department of Energy’s National Renewable Energy Laboratory.

The algorithms know the exact position of the sun for the next 100 years and enable each controller to position the trackers to maximize the incident radiation, thereby maximizing the amount of energy generated. The controller is also capable of reporting system and operational diagnostics out of the actuator via the operator panel. The controller is preprogrammed and the combiner box already wired, so startup is reduced from more than a day to just minutes.

“Once the GPS is hooked up and the controller knows position or latitude/longitude coordinates, the controller automatically acquires the time signal, position of the sun, automatically updates the position of the tracker and drives the tracker to its optimal position for maximum energy generation,” Sade says. “That makes all the difference in the world, especially for field technicians. Rather than doing a lot of complex programming it makes it easy for the customer. It even automatically positions the panel for storm conditions or maintenance.”

Profitable and Scalable

Sade says his customers measure profit by cost per watt. Keeping hardware and installation costs low while generating the most watts possible defines ROI. By using an RS485 cable, the S7-1200 controller can control actuators installed on up to 25 other trackers. This scalability, inherent with the S7-1200 controller, can be utilized for both large and small systems giving solar farm owners almost unlimited potential for adding new arrays.

“We are 25 to 42 percent more efficient than fixed mounted systems and our standalone solution can compete with utility grade trackers. This makes us very competitive on mid- and large-scale projects,” he says.

 Off The Shelf Products, Worldwide Support

“The reason I chose the S7-1200 over other controllers was because of the reliability, availability and standardization of the product around the world,” Sade says.  “Most trackers have reliability problems in the control panel.  The solar panels stop and don’t move. I wanted a product that creates the most reliable tracker in the world.”

Every S7-1200 comes with a memory card. In the event of a failure, a new controller is available off the shelf at electrical distributors on every continent. Replacement is easily accomplished by reloading the program from the memory card, Sade says. The availability of remote monitoring and diagnostics further enhances troubleshooting and maintenance, he says.

 

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