Uncertainty in the energy industry is primarily driven by cost, which begs the question, in a competitive renewables environment, which technology will emerge as the leader? In comparison with other renewable energy technologies such as wind or hydropower, solar power has the ability to emerge as a cost leader. In the photovoltaic (PV) sector, companies have increasingly concentrated their innovation efforts on cost reduction; improving efficiency has not been enough to ensure the technology’s competitiveness.

The reduction in module costs forces manufacturers to add value in other ways, beyond the module, by introducing advancements in BOS and manufacturing. The PV BOS market in general is in a healthy state and equipment revenues are projected to increase from $17 billion in 2011 to about $24 billion in 2016, according to IMS research. Monitoring hardware, mounting structures and tracker systems are expected to capture a growing share of the market.

To facilitate this promising market opportunity, there must be an industry-wide effort to accelerate cost-reduction opportunities for BOS components. Simple improvements in tracking and mounting technologies can decrease BOS costs in the PV sector by a noticeable amount. Moreover, these types of advancements not only make manufacturing modules less expensive and simpler, they also have the potential to improve the reliability of modules.

Overcapacity in the solar industry has led to a supply surplus, causing significant drops in module prices with solar panels falling more than 50 percent over the course of 2011, according to the Congressional Research Service. NPD Solarbuzz’ Marketbuzz also predicts that as this price trend continues, module prices should continue to fall by between 43 and 53 percent over the next five years. With price trends moving in this direction, manufacturers around the world are faced with the task of adding value to their modules in different ways, beyond the module itself, to remain competitive in the industry. Innovation in mounting systems can solve this problem by considerably decreasing BOS costs and, thus, decreasing the cost of the overall system.

Conventional mounting systems for frameless solar modules, such as clamps or so-called backrail systems, have proven to be unwieldy as well as time-, material- and cost-intensive, especially when handling larger frameless PV modules. Recent innovations in PV module mounting technology, however, can help meet these challenges. Using Oerlikon Solar’s successful innovation efforts as a model, other solar manufacturers can also develop inventive approaches to reduce costs within this competitive solar environment. MMI^TM (Module Mounting Interface) technology, for example, was developed by Oerlikon Solar and Schletter GmbH and provides a solution akin to the pushbutton principle. The module can be clicked into place on a rail-like fixture at any freely selectable spot – without using bolts and without needing to protect the PV module during the mounting process. MMI^TM designates the system’s anchors, which are attached to the backside of the PV module. When compared to conventional fastening methods, the PV module mounting time can be reduced by roughly half while the MMI^TM technology also reduces both the number and the size of mounting hardware components to such an extent that mounting material costs are slashed by roughly 20 percent. Relative to mounting devices for framed PV modules, the MMI^TM technology makes it possible to save approximately $13 (10 EUR) in material costs per PV module. Overall, this means that BOS costs – i.e. costs for all components except the module itself, like substructure, wiring and inverters – for unframed PV modules can be lowered by around 23 percent. This new mounting technology is suited not only to thin film silicon solar modules, but to all glass-glass modules, in which the cell matrix is located between two sheets of glass. MMI™ thus makes a substantial contribution to optimizing the cost structure of the photovoltaic sector as a whole – by minimizing the amount of components.

The cost reduction value associated with MMI™ or other mounting improvements can only be made possible by a comprehensive and holistic system overview that takes into account both the PV module and the BOS. This requires integrated collaboration between interdisciplinary experts and their teams. As companies continue to follow this holistic approach, further innovations like MMI^TM technology can be introduced to traditional mounting systems to reduce costs and increase module competitiveness.

Design advancements prove beneficial

As thin film manufacturers develop their mounting systems, design advancements are crucial and can prove beneficial in the long run. For instance, because neither bolts nor rubber straps nor any other fastening devices are required, MMI^TM components are nearly maintenance-free, offering multiple advantages over traditional mounting methods. In the long term, this presents a significant cost saving for facility operators. In addition to this system being less expensive and simpler, the lack of metal parts also improves the reliability of the module by avoiding any shorting problems that can occur. If manufacturers make these seemingly small but significant improvements to their mounting technologies, they will realize numerous advantages including less machine maintenance and fewer future complications.

Maximal module lifespan

Not only should mounting improvements aim to reduce costs, they should also strive to improve the general quality of PV modules to provide greater value. The MMI^TM technology is also an example of this by maximizing the lifespan of PV modules. It does this by optimally distributing the mechanical stresses generated over a module’s life cycle and preventing electrical interferences and delamination.

For thin film silicon modules produced by Oerlikon Solar facilities, six MMIs^TM are affixed in order to distribute mechanical stresses in the best possible way and prevent glass breakage. Unlike conventional methods, the MMIs™ can be positioned freely and thus optimally on the module backside according to PV module type.

With clamped and framed solutions, the washing out of dust can create liquid electrolytes around the mounting components (fixation), leading to a perpetually moist environment and thus delamination, including damaging of the foil. In addition, the use of rubber straps (ethylene propylene diene monomer or EPDM) does not provide sufficient insulation. Since EPDM displays a considerably lower electrical insulation value than glass, it functions like a conductive component. The resulting energy flows have a clear negative impact on module lifespan. However, with MMI™ technology the individual MMIs^TM are always well-insulated from the electric components.

The resulting performance with MMI™ technology after a so-called biased damp heat test (application of minus 1,000 volt applied to the system) following over 6,000 operating hours is only around 4 percent lower than initial performance – a level of performance that is superior to other PV module technologies that undergo the same biased damp heat test regimen. By expanding the lifespan of PV module technologies, manufacturers can quickly add value to the quality of their products despite the falling prices in the market.

Photovoltaics as a profitable source of energy

The MMI™ technology is already being used by Oerlikon Solar customers in the ongoing mass manufacturing of thin film silicon modules, and it is standing the test of practice. Of all solar processes, module manufacturers using this facility require the least energy. The so-called energy payback time, or the time required for the module to produce the amount of energy used in its manufacturing, is less than a year, well within reasonable business parameters.

As solar module prices continue to fall amid the supply glut, introducing advancements in mounting technology is one way for manufacturers to add value to PV modules. Companies can look to Oerlikon Solar’s success with MMI™ technology to introduce their own innovations into their respective mounting technologies in order to find ways to reduce BOS costs and improve the reliability and lifespan of PV modules. These advancements will allow solar PV to compete with other forms of renewable energy in an industry where different forms of energy are vying for leadership. Ultimately, these reduced BOS costs will ease uncertainty about the solar PV industry and make it more competitive with other energy sectors. 

The content & opinions in this article are the author’s and do not necessarily represent the views of AltEnergyMag

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