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Photovoltaics solar farms Tracker technologies and mounting methods Hill & Smith from the UK rely on panel slide-in systems with corresponding racking profiles.

1 Photovoltaics solar farms Tracker technologies and mounting methods Hill & Smith from the UK rely on panel slide-in systems with corresponding racking profiles. This is intended to further reduce time and material consumption and assembly costs. Photo: Hill & Smith When it comes to technology for solar farms, horizontal trackers are the big thing these days. As a cost-effective material for substructures, steel is still gaining ground. Other trends include using state-of-the-art technology and intelligent solutions in mounting technology, such as coatings. The U.S. economic research institute IHS expects annual growth rates of the global photovoltaics markets to surpass the 70-gigawatt mark by Some 47 GW was newly installed in 2014, which is 24 % more than in The segment of large-scale PV power stations was the driving force for this growth over the last few years, accounting for 30 % of the 170 GW installed around the world, and the outlook is equally bright for the coming years. Ground-mounted systems are the most important project type for large-scale power plants. Here, fixed mountings compete with tracking systems that include horizontal or vertical single-axis or dual-axis trackers. Project developers and solar farm operators are under pressure to reduce as much as possible the balance of system (BOS) costs for investments and the levelised cost of electricity (LCOE) in operation. Especially for trackers, this means using smart construction methods in order to keep expenses and costs for statics, laying foundations, required space, the number of fasteners, motors and controls just as low as maintenance costs and investment risk. Tracker business is growing While fixed mounting systems will continue to account for the greatest volume, single-axis horizontal trackers are the order of the day, not least because of requirements in energy management (afternoon peaks in countries with strong sun, sustained electricity production). With these systems, the panel surface rotates on a horizontal axis from the east to the west (see photo on page 60) throughout the day. A large number of new systems and drive technologies are 58 Sun & Wind Energy 4/2015

For Exotrack HZ V.2, panel frames are placed on central pivotal points above the posts. A sector gear is driven by a torque tube across the rows. Photo: Exosun currently being developed.

2 For Exotrack HZ V.2, panel frames are placed on central pivotal points above the posts. A sector gear is driven by a torque tube across the rows. Photo: Exosun currently being developed. According to another IHS study, tracker business is already on the rise. The global figure for single-axis trackers alone is expected to grow from 1.9 GW in 2014 to 9 GW in Sales for this type could reach approximately US$ 2 billion by then. The U.S. is regarded as the largest national market for single-axis tracker systems. Now that system prices have dropped considerably in the last few years, Chile, Mexico and other countries with high solar irradiation are also preferred target markets. The market for dual-axis trackers has collapsed because this technology is simply too costly, says Maria Lahuerta, Marketing Director for French tracker manufacturer Exosun SAS. Another drawback of the dual-axis tracker is the large amount of space needed because of mutual shadowing, which is especially detrimental in countries where space is precious. According to Lahuerta, horizontal trackers by contrast achieve the same utilization of space as fixed mounting systems while also having other significant benefits: Using the Exotrack HZ, we achieve 17 to 25 % higher yields at 15 % higher costs, depending on the site. She also said that up to 25 % higher yields might be possible, especially in the upcoming PV markets of the U.S. and Chile. The single-axis horizontal Exotrack HZ tracker is the flagship of the company, which was founded in 2007 and has so far built trackers for about 200 MW of PV. Exosun also has dual-axis trackers for concentrated solar PV in its portfolio. Internationalisation AS 2.1 INNOVATIVE PITCHED ROOF SYSTEM ALUMERO s most economical pv mounting system for pitched roofs is quick and easy to install. The system AS 2.1 scores with structurally optimized profiles and pre-mounted components. The ALUMERO SOLAR.PRO.TOOL supports you in the technical layout of the pv mounting system. It generates the project report, a material list and a verifiable structural calculation for your pv system. + EFFICIENT + PROFESSIONAL + FAST Learn more about AS 2.1 at: ALUMERO Systematic Solutions GmbH Sonnenweg Seeham. Austria T solar@alumero.at MADE IN EUROPE Solar Edition 59

Photovoltaics solar farms For their horizontal tracker, Array Technologies Inc. from the USA have moved the drive beneath the panel frames by means of a newly designed gear drive.

3 Photovoltaics solar farms For their horizontal tracker, Array Technologies Inc. from the USA have moved the drive beneath the panel frames by means of a newly designed gear drive. Photo: Array Technologies led to branch offices in the U.S., South Africa, Mexico, Brazil and Chile. In many countries, especially the ones mentioned with Exosun branches, local content requirements can be met. In a case study for a 12 MW project in Arizona (U.S.), Exosun compared the Exotrack HZ to a fixed mounting system (at 0 azimuth, 25 module tilt). The result shows that standard power purchase agreements (PPA) frequently found in the southwestern U.S. prove advantageous to tracking technology thanks to the high summer peak purchasing rates. Horizontal trackers increase annual energy yields by 20.8 % and revenue by 21.1 % compared to fixed mountings. For Exotrack HZ, module rows consist of up to 24 panels mounted vertically next to each other. Module frames are placed on central pivotal points above the posts. A sector gear driven by a torque tube across the rows moves the module row from east to west at an angle of up to ±50. At Intersolar Europe in Munich, Exosun presented the second generation of Exotrack HZ V2, which boasts an even more efficient drive and control system. One tracking motor can drive up to 30 rows, which is approximately equivalent to 200 kw. A control unit can now control up to 10 MW, a significant improvement over the previous 4 MW. We refer to Exotrack HZ as a low-impact tracker, says Lahuerta. She says that cranes aren t required for installation and that thanks to the relatively short module rows, the system adjusts to a site s topography quite well, as long as the downhill gradient is 10 % at most. Lahuerta says that the tracking motor s electricity consumption is only about 0.25 % of the yield, since the motor runs less than 30 minutes a day. Moreover, the motors are maintenance-free and greasing is not required. Recently, Exosun signed an agreement with Forza Systems in Mexico. The installation of a pilot plant in the state of Sonora, northern Mexico, is said to mark the beginning of a long-term cooperation. On the other side of the border, in the U.S. state of New Mexico, a 1.3 MW solar farm with new Duratrack HZ v3 trackers from Array Technologies Inc. was recently inaugurated. The company, also located in New Mexico, has been building trackers for 25 years and recently redesigned their horizontal tracker from the ground up. Before, the module rows central supporting tubes were driven directly, but across the rows. This required angular gears, which were placed outside the module rows. For version 3, the drive has migrated to beneath the module frames. To this end, the Americans have redesigned the drive with a focus on a large gear drive. According to Array Technologies, the design now permits a much higher energy density, especially since the distance between the modules was also reduced by 1 inch to ¼ inch. To achieve this, Array developed a new type of module fastening. Overall, the number of mounting points is said to have been diminished from 25,000 to 10,000 per MW; the number of driven posts was also reduced by 9 % thanks to a better balancing of loads. Moreover, only half as many motors and control units are needed one motor can now move 650 to 750 kw. Array is presenting the DuraTrack HZ v3 at the Intersolar North America in San Francisco soon. New suppliers Some German mounting system manufacturers who until now have only provided fixed ground-mounted systems have recently ventured into trackers and displayed their models at Intersolar Europe. While Habdank PV has designed a gear drive, Arausol and Schletter are banking on pushrods. According to Schletter, the company couples 16 rows per drive with each other using a standard mechanical pushrod. With this method, one drive can move about 1,200 m 2 of panels depending on local conditions. The Schletter FS Track-2 system is intended to be maintenance-free and provide a tracking range of up 60 Sun & Wind Energy 4/2015

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Photovoltaics solar farms At Intersolar Europe, Ideematec presented a tracker system with a drive for each row of panels that works with a universal shaft and steel ropes.

5 Photovoltaics solar farms At Intersolar Europe, Ideematec presented a tracker system with a drive for each row of panels that works with a universal shaft and steel ropes. Photo: Christian Dany to ±55. The company says backtracking retracting when long shadows are cast in winter means that the site can be more densely packed with PV. It also says that FS Track-2 is configured on a modular basis in line with site conditions and as the customer requires with a maximum extent of pre-assembly and only a small number of small parts for easy handling. The Arausol and Schletter systems are already on the market. Low-tension wire rope technology For a good two years now, tracker and mounting system manufacturer Ideematec has already had horizontal trackers in its portfolio. Ground-mounted systems with the safetrack Horizon have been installed in South Africa, Cyprus, Namibia, Chile, Germany, Mexico and Rwanda. With this system, each row of modules is provided with its own drive by means of a universal shaft with fixed drive via posts and steel cables. Ideematec does without drive trains between tracker rows, which means that the safetrack Horizon can follow slopes of up to 20 in all directions and installations can be carried out more rapidly and efficiently. Free access between the rows facilitates maintenance and mowing activities. For example, two module rows can be put in a V-position and cleaned simultaneously. On the other hand, an advantage of elements overarching the rows is that they can also serve as a path for DC cables, which need not be buried, thereby saving additional costs. In order to prevent damage to the tracker drive caused by the impact of wind on the module array, most systems need damping elements. SafeTrack Horizon is especially suitable for desert regions, because its patented tracking system using steel ropes eliminates the need for shock absorbers that are sensitive to sand, says Axel Hartung, Head of Sales and Marketing at Ideematec. He believes the company was recently awarded a contract for three power plants in Jordan thanks in large part to the robust steel rope technology. In April, Ideematec announced an order from Mexico. According to the company, safetrack Horizon s single-row layout was an advantage because of the often hilly, non-rectangular solar sites. Their horizontal tracker is suitable for all commercially available PV panels and can be equipped with up to two vertical or four horizontal panel rows. Krinner Schraubfundamente GmbH is also at work on a horizontal tracker that will be adjusted to their screw-in foundations. In May, Krinner announced that the foundation had been laid for the largest solar farm currently being built in Europe. In Cestas near Bordeaux, a 300 MW power station is being built that is fixed to the ground by 200,000 screw-in foundations (soil screws). The Krinner Flex V system is now being built as a substructure in a new east-west mounting solution. For planning and construction, Krinner used drones, GPS-controlled surveying robots and screwing machines. With the help of a drone flight, data were collected to establish a 3D model of the topography throughout the 260 hectares. A GPS-controlled robot then pre-drilled the holes at the points determined, before another machine screwed in the foundations. In Munich, Krinner recently demonstrated a machine that is supposed to perform surveying and screwing-in in one work step. It is fitted to a tractor and thanks to two lancets can screw in both foundations of one module row at the same time. Smart coatings German manufacturer Mounting Systems GmbH has expanded its range of ground-mounted systems with Sigma I XL Steel, which is completely made of steel components and more cost-effective than the XL aluminium variant. It is based on a row of posts and permits east-west ground slopes of up to 10. Framed or frameless modules can be mounted upright or transversely using time-saving Clickstone module clamps. A Magnelis coating is applied to the structural steelwork. This zinc-magnesium-aluminium coating from ArcelorMittal is self-restoring scratches cause no corrosion. Magnelis contains less zinc that can be flushed out into the earth and, for this reason, reduces the environmental impact. CWF GmbH specialises in ground-mounted support systems and also relies on the Magnelis coating for the substructure of their Vario system. Besides quality and durability, CWF owner Jürgen Wolpert also emphasises a logistical advantage: We can manufacture components and eliminate the cost and time-consuming process of batch galvanizing. In so doing, we 62 Sun & Wind Energy 4/2015

6 Want a revenue boooster? Krinner used GPS-controlled surveying robots and screwing machines for a 300 MW solar power plant in France. The screw-in foundations serve as a basis for an east-west mounting system. Photo: Krinner save one week of processing and are able to meet the short delivery deadlines often asked of us. He says that Magnelis can bridge and be self-restoring for laser cuts of up to 6 mm. When mounting modules, CWF gives clients the option of drill screws fitted with a separated bit drive that are intended to prevent theft. Facilitating assembly Another option for saving assembly time and therefore costs is module slide-in systems with corresponding racking profiles. This is the module mounting method that the solar division at Hill & Smith, an English infrastructure and galvanising producer, is focusing on. Modules can be easily inserted and engaged in the rack frame. No clamps are required, says Marketing Manager Michaela Moritz. Hill & Smith Solar is now launching a slide-in system that comes as a kit on the market. Our SolarKIT is a standardised system that is delivered complete with all components and is suitable for small-scale ground-mounted systems between 3 kw and 1 MW. The rails are adapted to the most common panel frame heights. The customer can choose between tables for upright or transverse mounting, Moritz explains, adding that the system is based on single-row driven posts and very adaptable to varying project requirements. Since we keep the SolarKIT in stock, we can supply it to our customers in the UK within a few days and can also deliver it to international customers at fairly short notice. Our key market is our domestic market in England. However, we have already supplied projects in Germany, Bulgaria, Romania and Bosnia and Herzegovina, states Moritz. Hill & Smith Solar also have in their portfolio the Back-2-Back Rail insertion system and Omega Rail, a clamping system in which panels can be deposited on the system s rails, if the clamps are fastened. With the Back-2-Back Rail system, panels are secured after insertion using a screw that is applied from below and are therefore absolutely stable in position. Additional lateral cover plates serve as an anti-theft device. Both systems are made to measure. Hill & Smith usually install U-shaped spacers, which are separators made from plastics that are attached to a panel frame on all four sides. They prevent contact corrosion between aluminium and steel. All systems feature hot-dipped galvanised posts and rails with zinc-magnesium coating. Christian Dany LCOE * friendly solar tracker Boosts your revenue up to 5% more than any other tracker Discover how! * Levelized Cost Of Energy Discover Exotrack HZ Call now / or visit Solar Edition 63

safetrack Horizon The most flexible and economic tracking solution

safetrack Horizon The most flexible and economic tracking solution VERIFIED YIELD OPTIMIZATION The most economic form of solar tracking Photovoltaic trackers are the mounting systems you need for an evenly