Aluminum: forging the framework for solar power

Since the early 1900s, aluminum has staked its position as a valued material in the energy industry. Power transmission lines and elevated train electrical wiring were among the first to benefit from aluminum's electrical advantages.

By Jason Weber

During the Great Depression, the aluminum industry grew further as hydroelectric generation capacity expanded.

When the first electrical transmission network was built by Thomas Edison, aluminum was too expensive to be used for wiring, so he turned to copper.

Today, however, aluminum wiring is the first choice for utility and power transmission networks, and it will continue to play a role in solar and other renewable energy applications as well.

In years past, aluminum as a structural element for solar and renewable energy may have been held back due to its greater cost per pound relative to steel. But with greater demand for sustainable solutions, more people today are recognizing that aluminum's material cost is more than offset by a combination of its reduced mass, high corrosion resistance, and the reduced transportation and assembly costs. The conclusion is not always obvious when looking just at a bill for materials, but it becomes clear when looking at the entire system cost.

When properly sourced, aluminum structures for solar energy can have a lower installed cost than equivalent steel structures. Several factors influence this cost advantage; most notably, faster installation time and reduced shipping cost relative to steel-based PV structures.

Aluminum extrusions have been widely adopted by the PV Industry and have proven their value proposition as the de facto standard for module frames based on its variety of beneficial material characteristics, including:

• Versatility
• High strength-to-weight ratio
• Corrosion-resistance
• Recyclability

Versatility

Extruded aluminum is a highly versatile and easily customizable material. Other materials and forming processes require secondary operations to add detail into the part. This adds time and additional cost. Aluminum extrusions, however, are easily customizable. The shape of an extrusion can be changed to simply "move" the metal as needed to create the desired feature. Furthermore, tooling costs for aluminum extrusions are relatively low compared to other types of production methods which, again, adds to the versatility and ability to customize the aluminum profile.

Strength-to-Weight Ratio

Aluminum extrusions' unique combination of high strength and low weight makes them ideal for applications like aerospace, transportation, and rooftop PV where load carrying ability and weight are key performance criteria.

Corrosion-Resistance

Aluminum extrusions offer excellent inherent corrosion resistance. They do not rust, and the aluminum surface is protected by its own naturally occurring oxide file, a protection that can be enhanced by anodizing or other finishing processes.

Recyclability

Not least of all, aluminum is a fully recyclable material that continues to provide value throughout its lifecycle. Indirectly, its recyclability helps aluminum conserve production energy as its products are created. So, although steel still has application in the renewable industry, aluminum continues to find new uses and is inherently more recyclable than galvanized steel. This fact is reflected most clearly in the differential between the cost of primary metal versus its scrap value. Using a large scale ground mount system as a basis for comparison, the residual value of an aluminum structure is worth three times as much as its galvanized steel counterpart when it is decommissioned.

As a result of its strength and value, aluminum extrusions are commonly found as key components in both residential and commercial rooftop PV mounting structures. For in-ground mounted PV installations, aluminum extrusions have also found a place, but are not yet as widely used as galvanized steel structures. As the industry continually looks for strategies to reduce total PV system cost, developers need to consider all of the arguments in favor of incorporating alternative material systems into their installations.

As we look ahead, I believe key decision makers are and will continue to realize the benefits associated with using aluminum extrusions in their PV mounting structures. The future for solar is bright with aluminum.

Jason Weber is the Director of Business Development for Energy and Industrial Products at Sapa Extrusions North America. With over 18 years of experience in the aluminum extrusion industry, Weber and his team are responsible for increasing extruded aluminum content, promoting Sapa's brand, and developing local and global product strategies within the Energy and Industrial Product segments. Weber is a member of the Aluminum Extruders Council and holds a Bachelor of Science degree in Business Administration and Marketing from Minot State University in North Dakota.