The Basics of Solar Industry Fasteners

Aside from helping to protect the environment through the reduction of fossil fuel consumption, solar power also boosts the economy — providing jobs, adding to the technology base, and giving businesses opportunities for cost savings on operating expenses.

Solar power was the fastest-growing source of new energy globally in 2016, the latest year for which data is available, outpacing growth in all other forms of power generation for the first time. And the future is only getting brighter: The International Energy Agency (IEA) predicts that solar energy will continue to dominate the alternative energy sector, with global capacity in five years expected to be greater than the current combined total of India and Japan’s power capabilities.

Commercial solar energy systems work in five steps:

Solar power systems collect and concentrate sunlight
The sunlight is used to heat a heat-transfer fluid that absorbs the solar energy and can then be transported to a heat exchanger
The superheated heat-transfer fluid is used to produce steam
The steam spins turbines to power a generator
The generator produces electricity for use and distribution.

Types of Solar Energy Systems

There are several kinds of solar energy systems in use today. Linear concentration systems are perhaps the most recognizable solar power configuration. They utilize long, rectangular mirrors with a slight U-shaped or parabolic curve to reflect light onto a receiver pipe that runs along their length and carries the heat-transfer fluid. The most common type of linear concentration system is the parabolic trough system, which can focus the sun anywhere from 30 to 100 times its usual intensity on the receiver pipe, significantly increasing heat generation and, in turn, power production.

Solar power towers are another popular system. Towers use the same basic components as linear concentration systems — namely, reflectors and receivers. However, the reflectors used in tower systems are flat, rather than curved, allowing them to reflect light to a receiver at the top of the tower. Finally, solar dish/engine systems utilize flat reflectors on a movable unit akin to a satellite dish. The receiver is extended in front of the unit on an arm.

Selection Considerations for Fasteners Used in the Solar Industry

To ensure optimal solar energy system performance, fasteners must be able to meet the demands of the industry's environmental and operational conditions. First, they should be simple and easy to install, as solar energy system installations are being completed at an accelerated pace, driven by favorable tax incentives and increased national emphasis on renewable forms of energy. Fasteners must also be reliable and durable, able to withstand the anticipated operational environmental profile that includes extreme temperatures, high winds, and icy or wet conditions. The impact of repeated thermal cycling also needs to be factored into the selection process, to prevent fasteners from becoming loose and necessitating repeated field maintenance activity. Proper mechanical locking to prevent under- and over-torquing, which can strip and loosen joints, as well as vibration resistance from wind buffeting should be considered in the design and selection process. Finally, as many commercial solar energy systems are unmanned or minimally staffed, some consideration to assuring tamper-proof joints and minimizing the potential for theft or vandalism is necessary.

Depending on the specific application, solar power installations typically require a range of fastening hardware products. Many of these are standard items, including threaded fasteners such as screws and machine bolts, along with washers, shims, and nuts. Other fastener products used in the installation of solar energy systems are specialty items, built to the design specifications for the specific component on which they are used. In all cases, corrosion resistance is critical given the exposed outdoor environment, making stainless steel fasteners particularly well-suited for use. While other materials such as plastics can also resist corrosion, their relatively low melting temperature may reduce their mechanical strength compared to steel-based fasteners.

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Renewable energy accounted for two-thirds of new power added to global grids in 2016, with solar energy showing the biggest growth. As the industry continues to expand, companies must ensure they’re using high-quality, durable fasteners to reduce the risk of disruptions while ensuring optimal performance and safety.

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