Although the manufacture of aluminum is itself an energy-intense process, many do not realize the role aluminum plays in the power grid and power generation industries. It turns out that aluminum has many attributes that make it an essential material when it comes to the ability to efficiently generate and transmit electricity over long distances. Anyone working in these fields is familiar with the many aluminum alloys used in electrical power applications.
Although aluminum has only been commercially viable for the past one hundred years or so, it’s one of the most abundant materials on the planet. When you combine that with its many desirable qualities, there’s little wonder why aluminum is so commonly found in the power generation and supply industries. This includes traditional coal and natural gas generation as well as new renewable technologies such as wind and solar.
Moving forward, the increase in renewable sources of power in national grid systems around the world will require an extensive overall, which will create even more demand for aluminum alloys.
The History of Aluminum in Electrical Engineering
Aluminum was first used as a material for electrical wiring in the first part of the twentieth century. As the national grid expanded after World War II, aluminum was increasingly preferred over copper as a conductor of electricity thanks to its significant advantages in terms of weight and cost. Over the past few decades, aluminum alloys from the AA-8000 series have been accepted by the National Electrical Code and according to the Aluminum Association, the market for aluminum wiring has grown by 20 percent in the last ten years. (https://www.aluminum.org/product-markets/electrical)
When Thomas Edison created his first electrical transmission network in the late 1800’s, copper was the natural choice, as not only does it offer more electrical conductivity than aluminum and most other metals, it also was more readily available. In the late 19th century aluminum was considered a precious metal with prices that rivaled gold and silver, but it did not take long for the disadvantages of copper to become obvious. Not only was it heavier, but it also suffered from corrosion problems.
What are the Advantages of Aluminum in Electrical Applications?
With the discovery of practical mass production methods for aluminum processing, the price of aluminum quickly fell, making it a more affordable choice for manufacturers and designers. It takes an aluminum wire with a diameter 1.5 times that of copper to transmit the same amount of electricity, but that wire will be three times lighter, meaning that aluminum is a more efficient material for electrical applications. High voltage overhead power lines are manufactured from aluminum to reduce weight while supplying good conductivity.
Perhaps even more important, aluminum alloys offer much greater corrosion resistance. With recent advances in premium alloys, more and more companies are switching from copper to aluminum as electrical generation and transmission is not solely the concern of power companies. Automotive, aerospace and shipbuilding are just a few examples of industries that require electrical wiring to function properly.
It’s estimated that these companies are saving millions of dollars by making the switch to aluminum. (https://www.reuters.com/article/us-aluminium-copper-substitution/auto-power-firms-save-millions-swapping-copper-for-aluminum-idUSKCN0WH1RI) In addition to being cheaper, lighter weight and more corrosion resistant, aluminum also offers other advantages, such as greater efficiency, recyclability and more. There are also particular use cases in which steel was the default material, but aluminum is proving more reliable in these cases as well, particularly when you consider that aluminum does not spark in the way that steel can.
One application for aluminum with regards to power generation is busbar. This critical part is the metallic strip housed inside switchgear, panel boards, and busway enclosures and enables local high current power distribution. Because busbar is usually uninsulated, it needs to have sufficient stiffness to be supported by the insulated pillars. The busbar ensures there is enough cooling of the conductors. Aluminum, with its excellent thermal conductivity, is a great choice for busbar material.
The busway, or bus duct, can also made from aluminum, due to the drawbacks of steel. Because steel creates a magnetic field around the conductors, it can result in energy loss and increased temperature. This leads to a lower continuous current rating of the bus duct. To overcome this problem, at least one side of the bus duct enclosure should be made with a non-magnetic material, such as aluminum.
Both the 1XXX and 6XXX series of aluminum alloys offer good solutions to busbar and bus duct applications. 1370 is a 99.7% purity aluminum grade that has excellent electrical conductivity and corrosion resistance. 6101, alloyed with magnesium and silicon, couples higher mechanical properties with good electrical conductivity when higher strength is needed. 6101 is also easily extruded into custom profiles for critical applications where stock sizes are not appropriate.
The Role of Aluminum in Renewable Energy Generation
There is a large groundswell of support to transition away from traditional fossil fuel power generation towards renewable forms of energy, such as wind and solar. Aluminum can help with this transition in two important ways.
First, aluminum is used in many of the components for renewable energy production. For instance, in terms of solar power, aluminum extrusions are widely used in the construction of solar power generation equipment. Photovoltaic solar cell frames are commonly made from extruded aluminum profiles (these are the solar panels you’re likely to find on homes and businesses). These extrusions are lighter weight than steel, offer excellent durability and corrosion resistance and have tremendous flexibility in terms of their profile dimensions.
Concentrated solar power, the other method of solar power generation, involves large mirrors that reflect sunlight into a collection unit. The intense heat produces steam to drive turbine generators. These vast solar arrays need to withstand a variety of environmental conditions, from extreme heat to high winds to abrasion and more, while still maintaining the ability to perform flawlessly. Aluminum has proven one of the best materials for securing reflectors in these complicated systems.
Wind turbines also rely on aluminum. Wind turbines need to be both high strength and lightweight, which means that aluminum is a perfect option. While steel is often the first choice for the turbines themselves, aluminum can also be found in the other critical components of the system, including the tower platform, cooling system and more.
Besides the power generators themselves, the inconsistent and sporadic nature of renewable energy through our national power grid requires a major overhaul. Aluminum has an important role to play in this endeavor. As the market transitions to a national smart grid that offers greater versatility and diversity, aluminum will help ease and promote new advances, such as the ability to have individual homes generate their own electricity with solar cells and windmills, and even sell back any excess energy back to the grid.
Your Technical Services Professional
Aluminum alloys that are perfect for electrical systems and grids include those from the 1ххх, 6ххх and 8ххх series, but knowing which alloy performs best for any application requires a great deal of experience. That’s why it’s essential to work with an aluminum supplier with a proven track record of success when it comes to helping their clients.
Clinton Aluminum’s team of experienced professionals is committed to working with industry to supply the right material for any given job. Contact a friendly and knowledgeable representative today to learn more.